Reactive oxygen species in cardiovascular disease

Facile Synthesis of a H2O2-Responsive Alternating Copolymer Bearing Thioether Side Groups for Drug Delivery and Controlled Release

A novel amphiphilic alternating copolymer with thioether side groups (P(MSPA-a-EG)) was synthesized through an amine-epoxy click reaction of 3-(methylthio)propylamine (MSPA) and ethylene glycol diglycidyl ether. P(MSPA-a-EG) was characterized in detail by nuclear magnetic resonance (NMR), gel permeation chromatography, Fourier transformed infrared, differential scanning calorimeter, and thermogravimetric analysis to confirm the successful synthesis. Due to its amphiphilic structure, P(MSPA-a-EG) could self-assemble into spherical micelles with an average diameter of about 151 nm. As triggered by H2O2, theses micelles could disassemble because hydrophobic thioether groups are transformed to hydrophilic sulfoxide groups in MSPA units. The oxidant disassemble process of micelles was systemically studied by dynamic light scattering, transmission electron microscopy, and 1H NMR measurements. The MTT assay against NIH/3T3 cells indicated that P(MSPA-a-EG) micelles exhibited good biocompatibility. Furthermore, they could be used as smart drug carriers to encapsulate hydrophobic anticancer drug doxorubicin (DOX) with 4.90% drug loading content and 9.81% drug loading efficiency. In vitro evaluation results indicated that the loaded DOX could be released rapidly, triggered by H2O2. Therefore, such a novel alternating copolymer was expected to be promising candidates for controlled drug delivery and release.

Short-Term Betanin Intake Reduces Oxidative Stress in Wistar Rats

Oxidative stress is a common condition described in risk factors for cardiovascular disease. Betanin, a bioactive pigment from red beetroot demonstrates anti-inflammatory and antioxidant properties. The main aim of this study was to evaluate the short-term intake of betanin against oxidative stress in a rodent model, a common condition described in several risk factors for cardiovascular disease. Oxidative stress was induced in Wistar rats by a hyperlipidemic diet for 60 days, followed by betanin administration (20 mg·kg-1) through oral gavage for 20 days. Plasma biochemical parameters and antioxidant enzyme activities were evaluated. Lipid peroxidation and histopathological changes were determined in the liver. The hyperlipidemic diet caused hyperglycemia, hyperinsulinemia, insulin resistance, and increases in alanine transaminase and aspartate transaminase levels. Oxidative stress status was confirmed by reduction of antioxidant enzyme activities, increased lipid peroxidation, and liver damage. Purified betanin regulated glucose levels, insulin, and insulin resistance. Hepatic damage was reversed as evidenced by the reduction in alanine transaminase and aspartate transaminase levels and confirmed by histological analyses. Betanin reduced hepatic malondialdehyde and increased superoxide dismutase, catalase, and glutathione peroxidase activities. Short-term betanin intake modulated biochemical parameters, reversed hepatic tissue damage, and attenuated oxidative stress in Wistar rats.

Bioactive Compounds of Cooked Tomato Sauce Modulate Oxidative Stress and Arachidonic Acid Cascade Induced by Oxidized LDL in Macrophage Cultures

Sofrito is a mix of tomato, onion, garlic, and olive oil, which contains phenolic compounds and carotenoids. Consumption of tomato-based sofrito has been related to a lower risk of cardiovascular events, but the mechanisms behind such beneficial effects remain unclear. This study aimed to analyze the effects of representative sofrito compounds such as naringenin, hydroxytyrosol, lycopene, and β-carotene on mechanisms involved in the pathogenesis of atherosclerosis. We demonstrated that both phenolic compounds and both carotenoids studied were able to inhibit low density lipoproteins (LDL) oxidation, as well as oxidative stress and eicosanoid production induced by oxidized LDL (oxLDL) in macrophage cultures. These effects were not the consequences of disturbing oxLDL uptake by macrophages. Finally, we observed an additive effect of these sofrito compounds, as well as the activity of a main naringenin metabolite, naringenin 7-O-β-d-glucuronide on LDL oxidation and oxidative stress.

Anatomically specific reactive oxygen species production participates in Marfan syndrome aneurysm formation

Marfan syndrome (MFS) is a connective tissue disorder that results in aortic root aneurysm formation. Reactive oxygen species (ROS) seem to play a role in aortic wall remodelling in MFS, although the mechanism remains unknown. MFS Fbn1^C1039G/+ mouse root/ascending (AS) and descending (DES) aortic samples were examined using DHE staining, lucigenin‐enhanced chemiluminescence (LGCL), Verhoeff's elastin‐Van Gieson staining (elastin breakdown) and in situ zymography for protease activity. Fbn1^C1039G/+ AS‐ or DES‐derived smooth muscle cells (SMC) were treated with anti‐TGF‐β antibody, angiotensin II (AngII), anti‐TGF‐β antibody + AngII, or isotype control. ROS were detected during early aneurysm formation in the Fbn1^C1039G/+ AS aorta, but absent in normal‐sized DES aorta. Fbn1^C1039G/+ mice treated with the unspecific NADPH oxidase inhibitor, apocynin reduced AS aneurysm formation, with attenuated elastin fragmentation. In situ zymography revealed apocynin treatment decreased protease activity. In vitro SMC studies showed Fbn1^C1039G/+‐derived AS SMC had increased NADPH activity compared to DES‐derived SMC. AS SMC NADPH activity increased with AngII treatment and appeared TGF‐β dependent. In conclusion, ROS play a role in MFS aneurysm development and correspond anatomically with aneurysmal aortic segments. ROS inhibition via apocynin treatment attenuates MFS aneurysm progression. AngII enhances ROS production in MFS AS SMCs and is likely TGF‐β dependent.

Radiation-induced heart disease: a review of classification, mechanism and prevention

With the increasing incidence of thoracic tumors, radiation therapy (RT) has become an important component of comprehensive treatment. RT improves survival in many cancers, but it involves some inevitable complications. Radiation-induced heart disease (RIHD) is one of the most serious complications. RIHD comprises a spectrum of heart disease including cardiomyopathy, pericarditis, coronary artery disease, valvular heart disease and conduction system abnormalities. There are numerous clinical manifestations of RIHD, such as chest pain, palpitation, and dyspnea, even without obvious symptoms. Based on previous studies, the pathogenesis of RIHD is related to the production and effects of various cytokines caused by endothelial injury, inflammatory response, and oxidative stress (OS). Therefore, it is of great importance for clinicians to identify the mechanism and propose interventions for the prevention of RIHD.

Thymosin alpha-1; a natural peptide inhibits cellular proliferation, cell migration, the level of reactive oxygen species and promotes the activity of antioxidant enzymes in human lung epithelial adenocarcinoma cell line (A549)

This research was conducted to investigate the biochemical effects of thymosin alpha-1 using human lung cancer cells (A549). The A549 cells were treated with different concentrations of Thα1 for 24 h and the growth, inhibition of cells was determined. Thα1 revealed anti-proliferative effect at 24 and 48 μg/ml after 24 h. Furthermore, it indicated antioxidant properties by significantly enhancing the activity of catalase (12 μg/ml), superoxide dismutase (6 and 12 μg/ml), and glutathione peroxidase (3, 6 and 12 μg/ml) and reducing the production of cellular ROS. Our results showed that Thα1 inhibits the migration of A549 cells in a concentration-dependent manner after 24 and 48 h. Moreover, the effect of Thα1 on apoptosis was investigated by Hoechst 33342 staining and cell cycle analysis. Results demonstrated no significant effect on the induction of apoptosis in A549 cells. In conclusion, our results showed the antioxidant properties of Thα1 on A549 cancer cells.

Trolox prevents high glucose-induced apoptosis in rat myocardial H9c2 cells by regulating GLUT-4 and antioxidant defense mechanism

Redox imbalance due to hyperglycemia is a causative factor for an increased generation of reactive oxygen species (ROS) that leads to mitochondrial dysfunction and the release of cytochrome-c. The aim of the present study is to elucidate the functional role of oxidative stress (OS) in the induction of apoptosis in H9c2 cells in the hyperglycemic state through glucose transporter-4 (GLUT-4) regulation and antioxidant status. H9c2 cells were incubated with 15, 24, and 33 mM glucose for 24, 48, and 72 hr to induce hyperglycemic stress. Hyperglycemic episodes have significantly influenced GLUT-4 mRNA regulation, depleted glutathione (GSH) and its associated enzymes, reduced cellular antioxidant enzymes (AOEs), caused nuclear condensation, and induced apoptosis by activating caspase-9 and 3 and annexin V binding in a concentration and duration-dependent manner. Trolox pretreatment significantly enhanced the GLUT-4 mRNA and antioxidant defense mechanism, suppressed nuclear condensation, and prevented cytochrome-c release, thereby reducing mitochondrial-dependent apoptosis. The present study shows that the toxic effect of high glucose is significantly regulated and that OS induction can be prevented through a water-soluble vitamin E analog "Trolox" treatment.

Biological activities of the extracts and compounds from the bark of Pterocarya hupehensis skan

This study was undertaken in order to investigate the antioxidant, anti-inflammatory and antimicrobial activities of various fractions and compounds obtained from the bark of P. hupehensis. The ethyl acetate fraction exhibited strong antioxidant, anti-inflammatory and antimicrobial effects. Six compounds were isolated from this fraction, three of which showed antioxidant activity and anti-inflammatory activity. The biological activities and the active compounds of P. hupehensis were reported for the first time.

HIF-1α Preconditioning Potentiates Antioxidant Activity in Ischemic Injury: The Role of Sequential Administration of Dihydrotanshinone I and Protocatechuic Aldehyde in Cardioprotection

Aims: The management of myocardial ischemia has been challenged by reperfusion injury. Reactive oxygen species (ROS) production is the critical cause of reperfusion injury, but antioxidant treatment failed to gain satisfactory effects. We hypothesized that improvement of redox homeostasis by preconditioning regulation should potentiate the ability of antioxidants to protect the heart from reperfusion injury. Results: By phenotype-based screening, we identified that dihydrotanshinone I (DT) and protocatechuic aldehyde (PCA) potently protected cardiomyocytes through preconditioning regulation and antioxidant activity, respectively. DT induced transient ROS generation via reversible inhibition of mitochondrial respiratory complex I and thereby stabilizing HIF-1α, while PCA elevated the levels of reduced glutathione (GSH) by providing reducing equivalents to scavenge ROS. HIF-1α, stabilized by DT, transcriptionally upregulated Nrf2 and thereby activated antioxidant enzymes, potentiating PCA to protect cardiomyocytes from reperfusion injury by strengthening intrinsic ROS scavenging capacity. In rat ischemia/reperfusion (I/R) model, sequential administration of DT and PCA, but not in reverse, additively protected the heart from I/R injury, manifested by reduced infarct size and improved cardiac function. These results were further supported by sequential administration of metformin and vitamin E in the rat and porcine I/R models. Innovation and Conclusion: Our work demonstrates that preconditioning regulation of redox state is essential for antioxidants to protect the heart from I/R injury, providing a new direction for the treatment of myocardial injury.

Soluble ST2 promotes oxidative stress and inflammation in cardiac fibroblasts: an in vitro and in vivo study in aortic stenosis

Background: Soluble ST2 (interleukin 1 receptor-like 1) (sST2) is involved in inflammatory diseases and increased in heart failure (HF). We herein investigated sST2 effects on oxidative stress and inflammation in human cardiac fibroblasts and its pathological role in human aortic stenosis (AS).

Methods and results: Using proteomics and immunodetection approaches, we have identified that sST2 down-regulated mitofusin-1 (MFN-1), a protein involved in mitochondrial fusion, in human cardiac fibroblasts. In parallel, sST2 increased nitrotyrosine, protein oxidation and peroxide production. Moreover, sST2 enhanced the secretion of pro-inflammatory cytokines interleukin (IL)-6, IL-1β and monocyte chemoattractant protein-1 (CCL-2). Pharmacological inhibition of transcriptional factor nuclear factor κB (NFκB) restored MFN-1 levels and improved oxidative status and inflammation in cardiac fibroblasts. Mito-Tempo, a mitochondria-specific superoxide scavenger, as well as Resveratrol, a general antioxidant, attenuated oxidative stress and inflammation induced by sST2. In myocardial biopsies from 26 AS patients, sST2 up-regulation paralleled a decrease in MFN-1. Cardiac sST2 inversely correlated with MFN-1 levels and positively associated with IL-6 and CCL-2 in myocardial biopsies from AS patients.

Conclusions: sST2 affected mitochondrial fusion in human cardiac fibroblasts, increasing oxidative stress production and inflammatory markers secretion. The blockade of NFκB or mitochondrial reactive oxygen species restored MFN-1 expression, improving oxidative stress status and reducing inflammatory markers secretion. In human AS, cardiac sST2 levels associated with oxidative stress and inflammation. The present study reveals a new pathogenic pathway by which sST2 promotes oxidative stress and inflammation contributing to cardiac damage.

Role of flavonoids in thrombotic, cardiovascular, and inflammatory diseases

The failure of mechanisms of natural anti-coagulation either due to genetic impairment or due to severe external injuries may result in a condition called thrombosis. This is believed to be the primary cause for a variety of life-threatening conditions such as: heart attack, stroke, pulmonary embolism, thrombophlebitis, and deep venous thrombosis (DVT). The growing number of these incidents requires an alternative anti-coagulant or anti-thrombotic agent that has minimal side effects and improved efficiency. For decades, plant polyphenols, especially flavonoids, were known for their vital role in preventing various diseases such as cancer. Mitigating excessive oxidative stress caused by reactive oxygen species (ROS) with anti-oxidant-rich flavonoids may reduce the risk of hyper-activation of platelets, cardiovascular diseases (CVD), pain, and thrombosis. Furthermore, flavonoids may mitigate endothelial dysfunction (ED), which generally correlates to the development of coronary artery and vascular diseases. Flavonoids also reduce the risk of atherosclerosis and atherothrombotic disease by inhibiting excessive tissue factor (TF) availability in the endothelium. Although the role of flavonoids in CVD is widely discussed, to the best of our knowledge, their role as anti-thrombotic lead has not been discussed. This review aims to focus on the biological uses of dietary flavonoids and their role in the treatment of various coagulation disorders, and may provide some potential lead to the drug discovery process in this area.

Advanced age protects resistance arteries of mouse skeletal muscle from oxidative stress through attenuating apoptosis induced by hydrogen peroxide

KEY POINTS

Vascular oxidative stress increases with advancing age. We hypothesized that resistance vessels develop resilience to oxidative stress to protect functional integrity and tested this hypothesis by exposing isolated pressurized superior epigastric arteries (SEAs) of old and young mice to H₂ O₂ . H₂ O₂ -induced death was greater in smooth muscle cells (SMCs) than endothelial cells (ECs) and lower in SEAs from old vs. young mice; the rise in vessel wall [Ca²⁺ ]_i induced by H₂ O₂ was attenuated with ageing, as was the decline in noradrenergic vasoconstriction; genetic deletion of IL-10 mimicked the effects of advanced age on cell survival. Inhibiting NO synthase or scavenging peroxynitrite reduced SMC death; endothelial denudation or inhibiting gap junctions increased SMC death; delocalization of cytochrome C activated caspases 9 and 3 to induce apoptosis. Vascular cells develop resilience to H₂ O₂ during ageing by preventing Ca²⁺ overload and endothelial integrity promotes SMC survival.

ABSTRACT

Advanced age is associated with elevated oxidative stress and can protect the endothelium from cell death induced by H₂ O₂ . Whether such protection occurs for intact vessels or differs between smooth muscle cell (SMC) and endothelial cell (EC) layers is unknown. We tested the hypothesis that ageing protects SMCs and ECs during acute exposure to H₂ O₂ (200 µm, 50 min). Mouse superior epigastric arteries (SEAs; diameter, ∼150 µm) were isolated and pressurized to 100 cmH₂ O at 37˚C. For SEAs from young (4 months) mice, H₂ O₂ killed 57% of SMCs and 11% of ECs in males vs. 8% and 2%, respectively, in females. Therefore, SEAs from males were studied to resolve the effect of ageing and experimental interventions. For old (24 months) mice, SMC death was reduced to 10% with diminished accumulation of [Ca²⁺ ]_i in the vessel wall during H₂ O₂ exposure. In young mice, genetic deletion of IL-10 mimicked the protective effect of ageing on cell death and [Ca²⁺ ]_i accumulation. Whereas endothelial denudation or gap junction inhibition (carbenoxolone; 100 µm) increased SMC death, inhibiting NO synthase (l-NAME, 100 µm) or scavenging peroxynitrite (FeTPPS, 5 µm) reduced SMC death along with [Ca²⁺ ]_i . Despite NO toxicity via peroxynitrite formation, endothelial integrity protects SMCs. Caspase inhibition (Z-VAD-FMK, 50 µm) attenuated cell death with immunostaining for annexin V, cytochrome C, and caspases 3 and 9 pointing to induction of intrinsic apoptosis during H₂ O₂ exposure. We conclude that advanced age reduces Ca²⁺ influx that triggers apoptosis, thereby promoting resilience of the vascular wall during oxidative stress.

Association of environmental exposure with hematological and oxidative stress alteration in gasoline station attendants

Gasoline station attendants spend a great deal of their time in the direct exposure to noxious substances such as benzene and byproducts of gasoline combustion. Such occupational exposure increases the risk of oxidative stress. This study aimed to evaluate hematological and biochemical alterations among petrol station workers. Forty gas station attendants and 39 non-attendants were recruited as exposed and control subjects, respectively. Plasma samples were evaluated for hemoglobin, hematocrit, and red blood cell count via the Sysmex KX-21 analyzer. Then, oxidized hemoglobin, methemoglobin, and hemichrome were measured spectrophotometrically. Moreover, serum antioxidant capacity and protein oxidation were evaluated. The means ± SD of hemoglobin (16.76 ± 0.14 g/dl vs 15.25 ± 0.14 g/dl), hematocrit (49.11 ± 0.36% vs 45.37 ± 0.31%), RBC count (5.85 ± 0.06 mil/μl vs 5.33 ± 0.06 mil/μl), Met-HB (1.07 ± 0.07 g/dl vs 0.39 ± 0.04 g/dl), and hemichrome (0.80 ± 0.07 g/dl vs 0.37 ± 0.02 g/dl) in the exposed group were significantly greater than the control group (P < 0.001). The results of the independent-sample t test illustrated that the FRAP test value in the exposed group (0.23 ± 0.01 mM) was significantly lower than the control group (0.34 ± 0.01 mM), while the value of the plasma protein carbonyl test in the exposed group (7.47 ± 0.33 mmol/mg protein) was meaningfully greater than the control group (5.81 ± 0.19 mmol/mg protein) (P < 0.001). In conclusion, gas station attendants suffer from higher levels of oxidative stress, and they need to take antioxidants in order to minimize the effects of oxidative stress.

The Role of Endothelial Dysfunction in Peripheral Blood Nerve Barrier: Molecular Mechanisms and Pathophysiological Implications

The exchange of solutes between the blood and the nerve tissue is mediated by specific and high selective barriers in order to ensure the integrity of the different compartments of the nervous system. At peripheral level, this function is maintained by the Blood Nerve Barrier (BNB) that, in the presence, of specific stressor stimuli can be damaged causing the onset of neurodegenerative processes. An essential component of BNB is represented by the endothelial cells surrounding the sub-structures of peripheral nerves and increasing evidence suggests that endothelial dysfunction can be considered a leading cause of the nerve degeneration. The purpose of this review is to highlight the main mechanisms involved in the impairment of endothelial cells in specific diseases associated with peripheral nerve damage, such as diabetic neuropathy, erectile dysfunction and inflammation of the sciatic nerve.

Microvesicles: ROS scavengers and ROS producers

This review analyzes the relationship between microvesicles and reactive oxygen species (ROS). This relationship is bidirectional; on the one hand, the number and content of microvesicles produced by the cells are affected by oxidative stress conditions; on the other hand, microvesicles can directly and/or indirectly modify the ROS content in the extra- as well as the intracellular compartments. In this regard, microvesicles contain a pro-oxidant or antioxidant machinery that may produce or scavenge ROS: direct effect. This mechanism is especially suitable for eliminating ROS in the extracellular compartment. Endothelial microvesicles, in particular, contain a specific and well-developed antioxidant machinery. On the other hand, the molecules included in microvesicles can modify (activate or inhibit) ROS metabolism in their target cells: indirect effect. This can be achieved by the incorporation into the cells of ROS metabolic enzymes included in the microvesicles, or by the regulation of signaling pathways involved in ROS metabolism. Proteins, as well as miRNAs, are involved in this last effect.

Blockade of Transient Receptor Potential Vanilloid 4 Enhances Antioxidation after Myocardial Ischemia/Reperfusion

Antioxidative stress provides a cardioprotective effect during myocardial ischemia/reperfusion (I/R). Previous research has demonstrated that the blockade of transient receptor potential vanilloid 4 (TRPV4) attenuates myocardial I/R injury. However, the underlying mechanism remains unclear. The current study is aimed at investigating the antioxidative activity of TRPV4 inhibition and elucidating the underlying mechanisms in vitro and ex vivo. We found that the inhibiting TRPV4 by the selective TRPV4 blocker HC-067047 or specific TRPV4-siRNA significantly reduces reactive oxygen species (ROS) and methane dicarboxylic aldehyde (MDA) levels in H9C2 cells exposed to hypoxia/reoxygenation (H/R). Meanwhile, the activity of antioxidative enzymes, particularly superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), is enhanced. Furthermore, after H/R, HC-067047 treatment increases the expression of P-Akt and the translocation of nuclear factor E2-related factor 2 (Nrf2) and related antioxidant response element (ARE) mainly including SOD, GSH-Px, and catalase (CAT). LY294002, an Akt inhibitor, suppresses HC-067047 and specific TRPV4-siRNA-induced Nrf2 expression and its nuclear accumulation. Nrf2 siRNA attenuates HC-067047 and specific TRPV4-siRNA-induced ARE expression. In addition, treatment with LY294002 or Nrf2 siRNA significantly attenuates the antioxidant and anti-injury effects of HC-067047 in vitro. Finally, in experiments on isolated rat hearts, we confirmed the antioxidative stress roles of TRPV4 inhibition during myocardial I/R and the application of exogenous H₂O₂. In conclusion, the inhibition of TRPV4 exerts cardioprotective effects through enhancing antioxidative enzyme activity and expressions via the Akt/Nrf2/ARE pathway.

Palbociclib improves cardiac dysfunction in diabetic cardiomyopathy by regulating Rb phosphorylation

Diabetic cardiomyopathy (DCM) is a condition associated with significant structural changes including cardiac tissue necrosis, localized fibrosis, and hypertrophy of cardiomyocytes. This study sought to assess whether and how CDK4/6 inhibitor, Palbociclib, can attenuate DCM using a streptozotocin (STZ)-induced DCM model system. In this study, we found CDK4 and CDK6 expression are significantly increased the cardiac tissue of these mice. Palbociclib treatment after initial STZ administration attenuated oxidative stress and inflammation, thereby reducing cardiomyocyte death and preserving cardiac function in these animals. In addition, Rb phosphorylation induction was found in STZ-treated mice, which was inhibited by Palbociclib treatment. In summary, Palbociclib protects mice from damage associated with DCM pathway activation, making Palbociclib is a relevant therapeutic target in the context of DCM.

Selenium in Cardiac Surgery

Selenium (Se) is an essential trace element that plays a pivotal role in many of the body's regulatory and metabolic functions, especially during times of stress. After uptake, Se is incorporated into several Se-dependent proteins, which have potent anti-inflammatory and antioxidant capacities. Several observational clinical studies have demonstrated that Se deficiency can cause chronic cardiovascular diseases and aggravate organ dysfunction after cardiac surgery and that low levels of Se may be independently associated with the development of organ dysfunction after cardiac surgery. Based on these findings, several studies have investigated the effects of a perioperative Se supplementation strategy. Therefore, the present review describes in depth the pathophysiology and harmful stimuli during cardiac surgery, how Se may counteract these injuries, the different types of Se supplementation strategies that have been evaluated, and current evidence of its clinical significance.

Natural Antioxidant Anthocyanins-A Hidden Therapeutic Candidate in Metabolic Disorders with Major Focus in Neurodegeneration

All over the world, metabolic syndrome constitutes severe health problems. Multiple factors have been reported in the pathogenesis of metabolic syndrome. Metabolic disorders result in reactive oxygen species (ROS) induced oxidative stress, playing a vital role in the development and pathogenesis of major health issues, including neurological disorders Alzheimer's disease (AD) Parkinson's disease (PD). Considerable increasing evidence indicates the substantial contribution of ROS-induced oxidative stress in neurodegenerative diseases. An imbalanced metabolism results in a defective antioxidant defense system, free radicals causing inflammation, cellular apoptosis, and tissue damage. Due to the annual increase in financial and social burdens, in addition to the adverse effects associated with available synthetic agents, treatment diversion from synthetic to natural approaches has occurred. Antioxidants are now being considered as convincing therapeutic agents against various neurodegenerative disorders. Therefore, medicinal herbs and fruits currently receive substantially more attention as commercial sources of antioxidants. In this review, we argue that ROS-targeted therapeutic interventions with naturally occurring antioxidant flavonoid, anthocyanin, and anthocyanin-loaded nanoparticles might be the ultimate treatment against devastating illnesses. Furthermore, we elucidate the hidden potential of the neuroprotective role of anthocyanins and anthocyanin-loaded nanoparticles in AD and PD neuropathies, which lack sufficient attention compared with other polyphenols, despite their strong antioxidant potential. Moreover, we address the need for future research studies of native anthocyanins and nano-based-anthocyanins, which will be helpful in developing anthocyanin treatments as therapeutic mitochondrial antioxidant drug-like regimens to delay or prevent the progression of neurodegenerative diseases, such as AD and PD.

Epigenetic Down-Regulation of Sirt 1 via DNA Methylation and Oxidative Stress Signaling Contributes to the Gestational Diabetes Mellitus-Induced Fetal Programming of Heart Ischemia-Sensitive Phenotype in Late Life

Rationale: The incidence of gestational diabetes mellitus (GDM) is increasing worldwide. However, whether and how GDM exposure induces fetal programming of adult cardiac dysfunctional phenotype, especially the underlying epigenetic molecular mechanisms and theranostics remain unclear. To address this problem, we developed a late GDM rat model.

Methods: Pregnant rats were made diabetic on day 12 of gestation by streptozotocin (STZ). Experiments were conducted in 6 weeks old offspring.

Results: There were significant increases in ischemia-induced cardiac infarction and gender-dependent left ventricular (LV) dysfunction in male offspring in GDM group as compared to controls. Exposure to GDM enhanced ROS level and caused a global DNA methylation in offspring cardiomyocytes. GDM attenuated cardiac Sirt 1 protein and p-Akt/Akt levels, but enhanced autophagy-related proteins expression (Atg 5 and LC3 II/LC3 I) as compared to controls. Ex-vivo treatment of DNA methylation inhibitor, 5-Aza directly inhibited Dnmt3A and enhanced Sirt 1 protein expression in fetal hearts. Furthermore, treatment with antioxidant, N-acetyl-cysteine (NAC) in offspring reversed GDM-mediated DNA hypermethylation, Sirt1 repression and autophagy-related gene protein overexpression in the hearts, and rescued GDM-induced deterioration in heart ischemic injury and LV dysfunction.

Conclusion: Our data indicated that exposure to GDM induced offspring cardiac oxidative stress and DNA hypermethylation, resulting in an epigenetic down-regulation of Sirt1 gene and aberrant development of heart ischemia-sensitive phenotype, which suggests that Sirt 1-mediated signaling is the potential therapeutic target for the heart ischemic disease in offspring.

Acute oral toxicity and antioxidant studies of an amine-based diselenide

Background

Organochalcogen compounds have attracted the interest of a multitude of studies for their promising Pharmacological and biological activities. The antioxidant activity and acute toxicity of an organoselenium compound, 1-(2-(2-(2-(1-aminoethyl)phenyl)diselanyl)phenyl)ethanamine (APDP) was determined in mice.

Methods

Mice were randomly divided into four groups, with each group comprising of seven animals. Canola oil (1ml/kg of body weight) was administered to 1st group, while 2nd, 3rd & 4th groups were administered with 10 mg/kg, 30 mg/kg & 350 mg/kg of APDP respectively. APDP was administered by Intragastric gavage as a single oral dose.

Results

The APDP oral administration was found to be safe up to 350 mg/kg of body weight and no deaths of animals were recorded. The lethal dose 50 (LD₅₀) for APDP was determined at 72 h and was estimated to be > 350 mg/kg. After acute treatment, all mice were sacrificed by decapitation to determine the antioxidant enzymes and lipid peroxidation values for the treated mice liver. No fluctuation in lipid peroxidation, vitamin C and non protein thiol (NPSH) levels was observed due to the administration of APDP. hepatic α-ALA-D activity, catalase (CAT), superoxide dismutase (SOD) and the biochemical parameters were evaluated. Experimental observation demonstrated that APDP protected Fe(II) induced thiobarbituric acid reactive substances (TBARS) production in liver homogenate significantly (p < 0.05). The administration of APDP (an amine-based diselenide) both in vitro and in vivo clearly demonstrated that this potential compound has no acute toxicity towards mice among all the tested parameter.

Conclusion

On the basis of experimental results, it is concluded that APDP is a potential candidate as an antioxidant compound for studying pharmacological properties.

Cardiac Resynchronisation Therapy and Cellular Bioenergetics: Effects Beyond Chamber Mechanics

Cardiac resynchronisation therapy is a cornerstone in the treatment of advanced dyssynchronous heart failure. However, despite its widespread clinical application, precise mechanisms through which it exerts its beneficial effects remain elusive. Several studies have pointed to a metabolic component suggesting that, both in concert with alterations in chamber mechanics and independently of them, resynchronisation reverses detrimental changes to cellular metabolism, increasing energy efficiency and metabolic reserve. These actions could partially account for the existence of responders that improve functionally but not echocardiographically. This article will attempt to summarise key components of cardiomyocyte metabolism in health and heart failure, with a focus on the dyssynchronous variant. Both chamber mechanics-related and -unrelated pathways of resynchronisation effects on bioenergetics - stemming from the ultramicroscopic level - and a possible common underlying mechanism relating mechanosensing to metabolism through the cytoskeleton will be presented. Improved insights regarding the cellular and molecular effects of resynchronisation on bioenergetics will promote our understanding of non-response, optimal device programming and lead to better patient care.

Discovery of the mechanisms and major bioactive compounds responsible for the protective effects of Gualou Xiebai Decoction on coronary heart disease by network pharmacology analysis

BACKGROUND

Gualou Xiebai decoction (GLXB), a multi-component herbal formula, has been widely used to treat coronary heart disease (CHD) in China for centuries. Several studies have revealed part of its pharmacological activities, whereas its active compounds and mechanisms of action are still unknown because of its complex composition.

PURPOSE

Discover the major active compounds and the pharmacological mechanisms of GLXB by network pharmacology methods.

METHODS

The main candidate target network was constructed by predicting targets of absorbable chemical compounds of GLXB, collecting therapeutic targets of cardiovascular drugs, constructing target network and layers of screening. Community detection and edge-betweenness calculation were applied to analyze the main candidate target network. Cell viability test, Western blot and flow cytometry were performed to validate the predicted results in cardiomyocytes hypoxia/reoxygenation model.

RESULTS

Five clusters and eight cross-talk targets were found in the main candidate target network. Their functions combined together might explain the multifunctional role of GLXB against CHD. Among the cross-talk targets, ESR1 (Estrogen receptor alpha, ERα) and MAPK14 (Mitogen-activated protein kinase 14, p38) were both drug targets and therapeutic targets whose interaction exhibited the greatest edge-betweenness value, suggesting their crucial role in the protective effect of GLXB. The compounds targeting on ESR1 and MAPK14 were identified as apigenin and 25S-macrostemonoside P respectively which were regard as the major bioactive compounds. The predicted results including the major bioactive compounds, their targets and the synergic effects between them were validated.

CONCLUSION

This study screened out major bioactive compounds from GLXB and offered a new understanding of the protection mechanism of GLXB against CHD by network pharmacology method and provides a combination strategy to explore mechanisms of action of multi-component drugs from a holistic perspective.

Combined exercise training improves blood pressure and antioxidant capacity in elderly individuals with hypertension

Background/objective

Although regular exercise plays a role in achieving healthy aging, a specific mode of exercise may be required for elderly individuals with hypertension (HT). Therefore, this study aimed to assess the effects of combined endurance and strength training (CBT) on blood pressure (BP) and antioxidant capacity in elderly individuals with HT.

Methods

In a single-blinded, randomized controlled trial, 54 older men and women aged 67 ± 5.8 years completed endurance training (ET, n = 13), strength training (ST, n = 13), combined endurance and strength training (CBT, n = 16) or served as controls (CON, n = 12). The intervention was a supervised exercise training (1-h sessions, three per week for 12 weeks), followed by a self-supervised exercise training for 12 weeks. Measurements of BP, glutathione peroxidase (GPx), total nitrite/nitrate (NOx-), malondialdehyde (MDA), and high-sensitive C-reactive protein (hs-CRP) were obtained before and after the supervised and the self-supervised periods.

Results

After the supervised period, systolic BP (SBP) decreased by 7.9% in the ET (p < 0.05) and 8.2% in the CBT (p < 0.01); GPx activity increased by 41.3% in the ET (p < 0.01), 19.1% in the ST (p < 0.05), and 49.2% in the CBT (p < 0.01); NOx-concentrations increased by 66.2% in the ET and 71.9% in the CBT (both p < 0.01), MDA concentrations decreased by 65.1% in the ST (p < 0.05) and 61% in the CBT (p < 0.01); hs-CRP concentrations decreased by 49.2% in only the CBT (p < 0.05). After the self-supervised period, SBP decreases by 7.5% in only the CBT (p < 0.01); NOx-concentrations increased by 68.5% in the ET and 92.4% in the CBT (both p < 0.01). However, there was no significant difference in SBP, GPx activity, NOx-, MDA and hs-CRP concentrations between the training groups.

Conclusion

The hypotensive and antioxidant effects of the CBT seem to be similar to the ET after the supervised training period. However, after the self-supervised training period, the CBT program might affect better due to greater exercise adherence and attendance in elderly individuals with HT.

Attenuation of the effects of oxidative stress by the MAO-inhibiting antidepressant and carbonyl scavenger phenelzine

Phenelzine (β-phenylethylhydrazine) is a monoamine oxidase (MAO)-inhibiting antidepressant with anxiolytic properties. It possesses a number of important pharmacological properties which may alter the effects of oxidative stress. After conducting a comprehensive literature search, the authors of this review paper aim to provide an overview and discussion of the mechanisms by which phenelzine may attenuate oxidative stress. It inhibits γ-aminobutyric acid (GABA) transaminase, resulting in elevated brain GABA levels, inhibits both MAO and primary amine oxidase and, due to its hydrazine-containing structure, reacts chemically to sequester a number of reactive aldehydes (e.g. acrolein and 4-hydroxy-2-nonenal) proposed to be implicated in oxidative stress in a number of neurodegenerative disorders. Phenelzine is unusual in that it is both an inhibitor of and a substrate for MAO, the latter action producing at least one active metabolite, β-phenylethylidenehydrazine (PEH). This metabolite inhibits GABA transaminase, is a very weak inhibitor of MAO but a strong inhibitor of primary amine oxidase, and sequesters aldehydes. Phenelzine may ameliorate the effects of oxidative stress by reducing formation of reactive metabolites (aldehydes, hydrogen peroxide, ammonia/ammonia derivatives) produced by the interaction of MAO with biogenic amines, by sequestering various other reactive aldehydes and by inhibiting primary amine oxidase. In PC12 cells treated with the neurotoxin MPP⁺, phenelzine has been reported to reduce several adverse effects of MPP⁺. It has also been reported to reduce lipid peroxidative damage induced in plasma and platelet proteins by peroxynitrite. In animal models, phenelzine has a neuroprotective effect in global ischemia and in cortical impact traumatic brain injury. Recent studies reported in the literature on the possible involvement of acrolein in spinal cord injury and multiple sclerosis indicate that phenelzine can attenuate adverse effects of acrolein in these models. Results from studies in our laboratories on effects of phenelzine and PEH on primary amine oxidase (which catalyzes formation of toxic aldehydes and is overexpressed in Alzheimer's disease), on sequestration of the toxic aldehyde acrolein, and on reduction of acrolein-induced toxicity in mouse cortical neurons are also reported.

Circulating microRNA-21 is an early predictor of ROS-mediated damage in subjects with high risk of developing diabetes and in drug-naïve T2D

BACKGROUND

Impaired glucose tolerance (IGT) is a risk factor for the development of diabetes and related complications that ensue. Early identification of at-risk individuals might be beneficial to reduce or delay the progression of diabetes and its related complications. Recently, microRNAs emerged as potential biomarkers of diseases. The aim of the present study was to evaluate microRNA-21 as a potential biomarker for the risk of developing diabetes in adults with IGT and to investigate its downstream effects as the generation of reactive oxygen species (ROS), the induction of manganese-superoxide dismutase-2 (SOD2), and the circulating levels of 4-HNE (4-hydroxynonenal).

METHODS

To evaluate the prognostic and predictive values of plasmatic microRNA-21 in identifying metabolic derangements, we tested a selected cohort (n = 115) of subjects enrolled in the DIAPASON Study, whom were selected on ADA criteria for 2hPG. Statistical analysis was performed using ANOVA or the Kruskal-Wallis test as appropriate. ROC curves were drawn for diagnostic accuracy of the tests; positive and negative predictive values were performed, and Youden's index was used to seek the cut-off optimum truncation point. ROS, SOD2 and 4-HNE were also evaluated.

RESULTS

We observed significant upregulation of microRNA-21 in IGT and in T2D subjects, and microRNA-21 was positively correlated with glycaemic parameters. Diagnostic performance of microRNA-21 was high and accurate. We detected significant overproduction of ROS by electron paramagnetic resonance (EPR), significant accumulation of the lipid peroxidation marker 4-HNE, and defective SOD2 antioxidant response in IGT and newly diagnosed, drug-naïve T2D subjects. In addition, ROC curves demonstrated the diagnostic accuracy of markers used.

CONCLUSIONS

our data demonstrate that microRNA-21 is associated with prediabetic status and exhibits predictive value for early detection of glucose imbalances. These data could provide novel clues for miR-based biomarkers to evaluate diabetes.

Assessment of Tumor Redox Status through (S)-4-(3-[18F]fluoropropyl)-L-Glutamic Acid PET Imaging of System xc - Activity

The cell's endogenous antioxidant system is vital to maintenance of redox homeostasis. Despite its central role in normal and pathophysiology, no noninvasive tools exist to measure this system in patients. The cystine/glutamate antiporter system xc - maintains the balance between intracellular reactive oxygen species and antioxidant production through the provision of cystine, a key precursor in glutathione biosynthesis. Here, we show that tumor cell retention of a system xc --specific PET radiotracer, (S)-4-(3-[18F]fluoropropyl)-L-glutamic acid ([18F]FSPG), decreases in proportion to levels of oxidative stress following treatment with a range of redox-active compounds. The decrease in [18F]FSPG retention correlated with a depletion of intracellular cystine resulting from increased de novo glutathione biosynthesis, shown through [U-13C6, U-15N2]cystine isotopic tracing. In vivo, treatment with the chemotherapeutic doxorubicin decreased [18F]FSPG tumor uptake in a mouse model of ovarian cancer, coinciding with markers of oxidative stress but preceding tumor shrinkage and decreased glucose utilization. Having already been used in pilot clinical trials, [18F]FSPG PET could be rapidly translated to the clinic as an early redox indicator of tumor response to treatment. SIGNIFICANCE: [18F]FSPG PET imaging provides a sensitive noninvasive measure of tumor redox status and provides an early marker of tumor response to therapy.See related commentary by Lee et al., p. 701.

Targeting Oxidative Stress Using Nanoparticles as a Theranostic Strategy for Cardiovascular Diseases

SIGNIFICANCE

Nanomedicine is an application of nanotechnology that provides solutions to unmet medical challenges. The unique features of nanoparticles, such as their small size, modifiable components, and diverse functionality, make them attractive and suitable materials for novel diagnostic, therapeutic, or theranostic applications. Cardiovascular diseases (CVDs) are the major cause of noncommunicable illness in both developing and developed countries. Nanomedicine offers novel theranostic options for the treatment of CVDs. Recent Advances: Many innovative nanoparticles to target reactive oxygen species (ROS) have been developed. In this article, we review the characteristics of nanoparticles that are responsive to ROS, their limitations, and their potential clinical uses. Significant advances made in diagnosis of atherosclerosis and treatment of acute coronary syndrome using nanoparticles are discussed.

CRITICAL ISSUES

Although there is a tremendous potential for the nanoparticle applications in medicine, their safety should be considered while using in humans. We discuss the challenges that may be encountered with some of the innovative nanoparticles used in CVDs.

FUTURE DIRECTIONS

The unique properties of nanoparticles offer novel diagnostic tool and potential therapeutic strategies. However, nanomedicine is still in its infancy, and further in-depth studies are needed before wide clinical application is achieved.

Cytoprotective and antioxidant effects of the red alga Alsidium corallinum against hydrogen peroxide-induced toxicity in rat cardiomyocytes

CONTEXT

Sepsis is the manifestation of the immune and inflammatory responses to infection that may ultimately result in multiorgan failure. Many substances are involved in myocardial dysfunction in sepsis, including hydrogen peroxide.

OBJECTIVE

This study evaluates the protective activity of the red alga Alsidium corallinum against hydrogen peroxide (H₂O₂)-induced toxicity in H9c2 cardiomyocytes.

MATERIAL AND METHODS

The biological properties of A. corallinum were firstly investigated. Secondly, the H9c2 cells were pre-treated with alga extract, and then exposed to H₂O₂.

RESULTS

Our results showed richness of the alga in antioxidant compounds, and its biological activities. H₂O₂ induced a morphological changes and decrease in H9c2 cell viability correlating with an increase in enzymatic and non-enzymatic antioxidants. Pre-treatment with A. corallinum, reduces toxicity and decreased the antioxidants status induced by H₂O₂.

CONCLUSION

These findings indicated for the first time the protective effect of A. corallinum against H₂O₂-induced toxicity in H9c2 cells.

Activation of Nrf2 by Phloretin Attenuates Palmitic Acid-Induced Endothelial Cell Oxidative Stress via AMPK-Dependent Signaling

Phloretin, a dihydrochalcone structural flavonoid compound, possesses antioxidant activity. In this study, we conducted studies to explore the function of phloretin on high palmitic acid-induced oxidative stress in human umbilical vein endothelial cells and investigated the potential mechanism using ribonucleic acid sequencing (RNA-Seq). Our findings reveal that phloretin significantly decreased the levels of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA), increased superoxide dismutase (SOD) and glutathione peroxidase-1 (Gpx-1) activity, and restored the loss of mitochondrial membrane potential (MMP). Next, whole transcriptome analysis was performed using RNA-Seq The results indicated more than 3000 differentially expressed genes (DEGs). Gene Ontology analysis revealed that the DEGs were categorized functionally, mainly by the biological processes, cell metabolism, and cellular response to chemical stimulus. The Kyoto Encyclopedia of Genes and Genomes indicated that they were mainly enriched in cAMP, apoptosis, and cytoskeletal regulation signaling pathways. Furthermore, on the basis of the results of RNA-Seq and Western blotting, our study verified that phloretin upregulated the expression of p-Nrf2 and HO-1 by promoting the phosphorylation of AMPK at Thr¹⁷² through activation of liver kinase B1. In conclusion, phloretin attenuates PA-induced oxidative stress in HUVECs via the AMPK/Nrf2 antioxidative pathway.

GLUT10 maintains the integrity of major arteries through regulation of redox homeostasis and mitochondrial function

Glucose transporter 10 (GLUT10) is a member of the GLUT family of membrane transporters, and mutations in this gene cause arterial tortuosity syndrome (ATS). However, the physiological role and regulation of GLUT10 in arteries remains unclear. To further understand its physiological roles in major arteries, we examined the regulatory mechanisms of GLUT10 in ASMCs and aortic tissues. Interestingly, we find that targeting of GLUT10 to mitochondria is increased in ASMCs under both stress and aging conditions, which enhances dehydroascorbic acid (DHA) uptake and maintains intracellular ascorbic acid (AA) levels. We further demonstrate that the targeting of GLUT10 to mitochondria is important to maintain redox homeostasis, mitochondrial structure and mitochondrial function in ASMCs. A missense mutation of GLUT10 (Glut10G128E) impairs mitochondrial targeting in ASMCs. Consequently, ASMCs isolated from Glut10G128E mice exhibit increased reactive oxygen species (ROS) levels, fragmented mitochondria and impaired mitochondrial function, as well as enhanced cell proliferation and migration. In vivo, mitochondrial structure is altered, and ROS levels are heightened in aortic tissues of Glut10G128E mice. Furthermore, increased number and disorganization of ASMCs, along with progressive arterial wall remodeling were observed in aortic tissues of Glut10G128E mice. These defects were coincident with elevated systolic blood pressure in aged Glut10G128E animals. Our results describe a novel mechanism that GLUT10 targeting to mitochondria under stress and aging condition has a critical role in maintaining AA levels, redox homeostasis and mitochondrial structure and function in ASMCs, which is likely to contribute to the maintenance of healthy vascular tissue.

ROS-triggered degradation of selenide-containing polymers based on selenoxide elimination

A degradable ROS responsive selenide-containing block polymer would undergo an oxidation-related elimination and degradation process.

Reactive oxygen species (ROS)-responsive biomaterials mediate tissue microenvironments and tissue regeneration

ROS-responsive biomaterials alleviate the oxidative stress in tissue microenvironments, promoting tissue regeneration and disease therapy.

Mass Spectrometry in Advancement of Redox Precision Medicine

Redox (portmanteau of reduction-oxidation) reactions involve the transfer of electrons between chemical species in biological processes fundamental to life. It is of outmost importance that cells maintain a healthy redox state by balancing the action of oxidants and antioxidants; failure to do so leads to a multitude of diseases including cancer, diabetes, fibrosis, autoimmune diseases, and cardiovascular and neurodegenerative diseases. From the perspective of precision medicine, it is therefore beneficial to interrogate the redox phenotype of the individual-similar to the use of genomic sequencing-in order to design tailored strategies for disease prevention and treatment. This chapter provides an overview of redox metabolism and focuses on how mass spectrometry (MS) can be applied to advance our knowledge in redox biology and precision medicine.

Structural characterization, antioxidant activity, and antiglycation activity of polysaccharides from different chrysanthemum teas

In this study, structural characteristics, antioxidant activity, and antiglycation activity of polysaccharides from different chrysanthemum teas were investigated and compared.

Sources of Vascular Nitric Oxide and Reactive Oxygen Species and Their Regulation

Nitric oxide (NO) is a small free radical with critical signaling roles in physiology and pathophysiology. The generation of sufficient NO levels to regulate the resistance of the blood vessels and hence the maintenance of adequate blood flow is critical to the healthy performance of the vasculature. A novel paradigm indicates that classical NO synthesis by dedicated NO synthases is supplemented by nitrite reduction pathways under hypoxia. At the same time, reactive oxygen species (ROS), which include superoxide and hydrogen peroxide, are produced in the vascular system for signaling purposes, as effectors of the immune response, or as byproducts of cellular metabolism. NO and ROS can be generated by distinct enzymes or by the same enzyme through alternate reduction and oxidation processes. The latter oxidoreductase systems include NO synthases, molybdopterin enzymes, and hemoglobins, which can form superoxide by reduction of molecular oxygen or NO by reduction of inorganic nitrite. Enzymatic uncoupling, changes in oxygen tension, and the concentration of coenzymes and reductants can modulate the NO/ROS production from these oxidoreductases and determine the redox balance in health and disease. The dysregulation of the mechanisms involved in the generation of NO and ROS is an important cause of cardiovascular disease and target for therapy. In this review we will present the biology of NO and ROS in the cardiovascular system, with special emphasis on their routes of formation and regulation, as well as the therapeutic challenges and opportunities for the management of NO and ROS in cardiovascular disease.

Role of pyroptosis in cardiovascular disease

Cardiac function is determined by the dynamic equilibrium of various cell types and the extracellular matrix that composes the heart. Cardiovascular diseases (CVDs), especially atherosclerosis and myocardial infarction, are often accompanied by cell death and acute/chronic inflammatory reactions. Caspase‐dependent pyroptosis is characterized by the activation of pathways leading to the activation of NOD‐like receptors, especially the NLRP3 inflammasome and its downstream effector inflammatory factors interleukin (IL)‐1β and IL‐18. Many studies in the past decade have investigated the role of pyroptosis in CVDs. The findings of these studies have led to the development of therapeutic approaches based on the regulation of pyroptosis, and some of these approaches are in clinical trials. This review summarizes the molecular mechanisms, regulation and cellular effects of pyroptosis briefly and then discusses the current pyroptosis studies in CVD research.

Protective Role of Endogenous Kallistatin in Vascular Injury and Senescence by Inhibiting Oxidative Stress and Inflammation

Kallistatin was identified in human plasma as a tissue kallikrein-binding protein and a serine proteinase inhibitor. Kallistatin exerts pleiotropic effects on angiogenesis, oxidative stress, inflammation, apoptosis, fibrosis, and tumor growth. Kallistatin levels are markedly reduced in patients with coronary artery disease, sepsis, diabetic retinopathy, inflammatory bowel disease, pneumonia, and cancer. Moreover, plasma kallistatin levels are positively associated with leukocyte telomere length in young African Americans, indicating the involvement of kallistatin in aging. In addition, kallistatin treatment promotes vascular repair by increasing the migration and function of endothelial progenitor cells (EPCs). Kallistatin via its heparin-binding site antagonizes TNF-α-induced senescence and superoxide formation, while kallistatin's active site is essential for inhibiting miR-34a synthesis, thus elevating sirtuin 1 (SIRT1)/eNOS synthesis in EPCs. Kallistatin inhibits oxidative stress-induced cellular senescence by upregulating Let-7g synthesis, leading to modulate Let-7g-mediated miR-34a-SIRT1-eNOS signaling pathway in human endothelial cells. Exogenous kallistatin administration attenuates vascular injury and senescence in association with increased SIRT1 and eNOS levels and reduced miR-34a synthesis and NADPH oxidase activity, as well as TNF-α and ICAM-1 expression in the aortas of streptozotocin- (STZ-) induced diabetic mice. Conversely, endothelial-specific depletion of kallistatin aggravates vascular senescence, oxidative stress, and inflammation, with further reduction of Let-7g, SIRT1, and eNOS and elevation of miR-34a in mouse lung endothelial cells. Furthermore, systemic depletion of kallistatin exacerbates aortic injury, senescence, NADPH oxidase activity, and inflammatory gene expression in STZ-induced diabetic mice. These findings indicate that endogenous kallistatin displays a novel role in protection against vascular injury and senescence by inhibiting oxidative stress and inflammation.

Phenelzine reduces the oxidative damage induced by peroxynitrite in plasma lipids and proteins

Peroxynitrite is a reactive nitrogen species produced in the intravascular compartment from superoxide anion and nitric oxide. Peroxynitrite destroys blood plasma proteins and membranes of red blood cells and of platelets. This explains why excessive production of peroxynitrite contributes to diseases and to ageing. Therapeutics that antagonize peroxynitrite may delay ageing and the progression of disease. We developed an in vitro assay that allows the investigation of the oxidative damage caused by peroxynitrite in the intravascular compartment. This assay correlates the damage with the rate of formation of protein carbonyl groups, 3-nitrotyrosine (3-NT) and thiobarbituric acid reactive substances. Using this assay, we evaluated the ability of phenelzine, a scavenger of reactive aldehydes, to antagonize the effects of peroxynitrite. Herein, we showed that phenelzine significantly decreased the lipid peroxidative damage caused by peroxynitirite in blood plasma and platelets. Moreover, it inhibited carbonyl group and 3-NT formation in blood plasma and platelet proteins.

Cytoprotective Effects of Natural Compounds against Oxidative Stress

Oxidative stress, an imbalance between reactive oxygen species and antioxidants, has been witnessed in pathophysiological states of many disorders. Compounds identified from natural sources have long been recognized to ameliorate oxidative stress due to their inherent antioxidant activities. Here, we summarize the cytoprotective effects and mechanisms of natural or naturally derived synthetic compounds against oxidative stress. These compounds include: caffeic acid phenethyl ester (CAPE) found in honey bee propolis, curcumin from turmeric roots, resveratrol abundant in grape, and 1-[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl] imidazole (CDDO-Im), a synthetic triterpenoid based on naturally occurring oleanolic acid. Cytoprotective effects of these compounds in diseases conditions like cardiovascular diseases and obesity to decrease oxidative stress are discussed.

Protocatechuic Acid Ameliorated Palmitic-Acid-Induced Oxidative Damage in Endothelial Cells through Activating Endogenous Antioxidant Enzymes via an Adenosine-Monophosphate-Activated-Protein-Kinase-Dependent Pathway

Protocatechuic acid (PCA, 3,4-dihydroxybenzoic acid), the main metabolite of anthocyanins, is widely distributed in fruits and vegetables and has been reported to possess a strong antioxidant activity. Herein, we aimed to investigate the protective effect of PCA against high palmitic-acid (PA)-induced oxidative damage and the underling molecular mechanisms in human umbilical vein endothelial cells (HUVECs). PCA reduced the levels of intracellular reactive oxygen species and malondialdehyde and increased the activities of endogenous antioxidant enzymes, including superoxide dismutase, glutathione peroxidase 1, and heme oxygenase 1 (HO-1). Metabolomic analysis showed that PCA affected numerous metabolites, especially some of which were related with energy metabolism. PCA also upregulated the phosphorylation of adenosine-monophosphate-activated protein kinase (AMPK) at Thr¹⁷² through activating liver kinase B1 and then promoted the expression of p-Nrf2 and HO-1. Moreover, PCA reversed the decreased expression of peroxisome proliferator-activated receptor γ coactivator 1α and significantly increased the mitochondrial density. Collectively, these results demonstrated that PCA attenuated PA-induced oxidative damage in HUVECs via an AMPK-dependent pathway.