Role of peroxynitrite in the pathogenesis of cardiovascular complications of diabetes

Mixture of Doxycycline, ML-7 and L-NAME Restores the Pro- and Antioxidant Balance during Myocardial Infarction-In Vivo Pig Model Study

The restoration of blood flow to the ischemic myocardium inflicts ischemia/reperfusion (I/R) heart injury (IRI). The main contributors to IRI are increased oxidative stress and subsequent excessive production of ROS, increased expression of NOS and peroxinitate, activation of MMPs, and enhanced posttranslational modifications of contractile proteins, which make them more susceptible to proteolytic degradation. Since the pathophysiology of IRI is a complex issue, and thus, various therapeutic strategies are required to prevent or reduce IRI and microvascular dysfunction, in the current study we proposed an innovative multi-drug therapy using low concentrations of drugs applied intracoronary to reach microvessels in order to stabilize the pro- and antioxidant balance during a MI in an in vivo pig model. The ability of a mixture of doxycycline (1 μM), ML-7 (0.5 μM), and L-NAME (2 μM) to modulate the pro- and antioxidative balance was tested in the left ventricle tissue and blood samples. Data showed that infusion of a MIX reduced the total oxidative status (TOS), oxidative stress index (OSI), and malondialdehyde (MDA). It also increased the total antioxidant capacity, confirming its antioxidative properties. MIX administration also reduced the activity of MMP-2 and MMP-9, and then decreased the release of MLC1 and BNP-26 into plasma. This study demonstrated that intracoronary administration of low concentrations of doxycycline in combination with ML-7 and L-NAME is incredibly efficient in regulating pro- and antioxidant balance during MI.

Regulatory role of peroxynitrite in advanced glycation end products mediated diabetic cardiovascular complications

The Advanced Glycation End Products (AGE) binding with its receptor can increase reactive oxygen species (ROS) generation through specific signaling mediators. The effect of superoxide (O2-) and O2- mediated ROS and reactive nitrogen species depends on their concentration and location of formation. Nitric oxide (NO) has anti-inflammatory and anticoagulant properties and a vasodilation effect, but NO can be deactivated by reacting with O2-. This reaction between NO and O2- produces the potent oxidant ONOO-. Therefore, ONOO-'s regulatory role in AGEs in diabetic cardiovascular complications must considered as a regulator of cardiovascular complications in diabetes.

Predictive biomarkers for the early detection and management of heart failure

Cardiovascular disease (CVD) is a serious public health concern whose incidence has been on a rise and is projected by the World Health Organization to be the leading global cause of mortality by 2030. Heart failure (HF) is a complicated syndrome resulting from various CVDs of heterogeneous etiologies and exhibits varying pathophysiology, including activation of inflammatory signaling cascade, apoptosis, fibrotic pathway, and neuro-humoral system, thereby leading to compromised cardiac function. During this process, several biomolecules involved in the onset and progression of HF are released into circulation. These circulating biomolecules could serve as unique biomarkers for the detection of subclinical changes and can be utilized for monitoring disease severity. Hence, it is imperative to identify these biomarkers to devise an early predictive strategy to stop the deterioration of cardiac function caused by these complex cellular events. Furthermore, measurement of multiple biomarkers allows clinicians to divide HF patients into sub-groups for treatment and management based on early health outcomes. The present article provides a comprehensive overview of current omics platform available for discovering biomarkers for HF management. Some of the existing and novel biomarkers for the early detection of HF with special reference to endothelial biology are also discussed.

Activatable Probes for Ratiometric Imaging of Endogenous Biomarkers In Vivo

Dynamic variations in the concentration and abnormal distribution of endogenous biomarkers are strongly associated with multiple physiological and pathological states. Therefore, it is crucial to design imaging systems capable of real-time detection of dynamic changes in biomarkers for the accurate diagnosis and effective treatment of diseases. Recently, ratiometric imaging has emerged as a widely used technique for sensing and imaging of biomarkers due to its advantage of circumventing the limitations inherent to conventional intensity-dependent signal readout methods while also providing built-in self-calibration for signal correction. Here, the recent progress of ratiometric probes and their applications in sensing and imaging of biomarkers are outlined. Ratiometric probes are classified according to their imaging mechanisms, and ratiometric photoacoustic imaging, ratiometric optical imaging including photoluminescence imaging and self-luminescence imaging, ratiometric magnetic resonance imaging, and dual-modal ratiometric imaging are discussed. The applications of ratiometric probes in the sensing and imaging of biomarkers such as pH, reactive oxygen species (ROS), reactive nitrogen species (RNS), glutathione (GSH), gas molecules, enzymes, metal ions, and hypoxia are discussed in detail. Additionally, this Review presents an overview of challenges faced in this field along with future research directions.

A new modified pterocarpan glycoside from Sophora flavescens

Sophora flavescens is a widely used traditional Chinese herbal medicine. In this work, a new pterocarpan glycoside, kurarinol C (1) together with six known compounds, sophoracarpan A (2), trifohrhizin-6'-monoacetate (3), trifohrhizin (4), maackiain (5), (6S,6aS,11aR）-6α-methoxy-pterocarpin (6), L-maackiain (7) were isolated from the roots of S. flavescens. Among them, compounds 2 and 6 were discovered from S. flavescens for the first time. Their chemical structures were elucidated on the basis of extensive NMR and MS analyses. Furthermore, the antioxidant activities of these compounds were evaluated by the ABTS and DPPH free radical scavenging assay. Three compounds (5, 6, 7) exhibited stronger antioxidant capacity against the ABTS enzyme at 20 µg/mL (scavenging rates > 55%).

Anti-inflammatory and antioxidant actions of extracts from Rheum rhaponticum and Rheum rhabarbarum in human blood plasma and cells in vitro

Rheum rhaponticum L. (rhapontic rhubarb) and Rheum rhabarbarum L. (garden rhubarb) are edible and medicinal rhubarb species used for many centuries in traditional medicine. This work is focused on the biological activity of extracts from petioles and roots of R. rhaponticum and R. rhabarbarum as well as rhapontigenin and rhaponticin, typical stilbenes present in these rhubarbs, in a context of their effects on blood physiology and cardiovascular health. Anti-inflammatory properties of the examined substances were evaluated in human peripheral blood mononuclear cells (PBMCs) and THP1-ASC-GFP inflammasome reporter cells. Due to the coexistence of inflammation and oxidative stress in cardiovascular diseases, the study design included also antioxidant assays. This part of the work involved the assessment of the protective efficiency of the examined substances against the peroxynitrite-triggered damage to human blood plasma components, including fibrinogen, a protein of critical importance for blood clotting and maintaining the haemostatic balance. Pre-incubation of PBMCs with the examined substances (1-50 μg/mL) considerably decreased the synthesis of prostaglandin E2 as well as the release of pro-inflammatory cytokines (IL-2 and TNF-α) and metalloproteinase-9. A reduced level of secreted apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) specks in the THP-1-ASC-GFP cells was also observed. The examined substances significantly diminished the extent of ONOO‾induced oxidative modifications of blood plasma proteins and lipids and normalized, or even strengthened blood plasma antioxidant capacity. Furthermore, a reduction of oxidative damage to fibrinogen, including modifications of tyrosine and tryptophan residues along with the formation of protein aggregates was found.

The damaging duo: Obesity and excess dietary salt contribute to hypertension and cardiovascular disease

Hypertension is a primary risk factor for cardiovascular disease. Cardiovascular disease is the leading cause of death among adults worldwide. In this review, we focus on two of the most critical public health challenges that contribute to hypertension-obesity and excess dietary sodium from salt (i.e., sodium chloride). While the independent effects of these factors have been studied extensively, the interplay of obesity and excess salt overconsumption is not well understood. Here, we discuss both the independent and combined effects of excess obesity and dietary salt given their contributions to vascular dysfunction, autonomic cardiovascular dysregulation, kidney dysfunction, and insulin resistance. We discuss the role of ultra-processed foods-accounting for nearly 60% of energy intake in America-as a major contributor to both obesity and salt overconsumption. We highlight the influence of obesity on elevated blood pressure in the presence of a high-salt diet (i.e., salt sensitivity). Throughout the review, we highlight critical gaps in knowledge that should be filled to inform us of the prevention, management, treatment, and mitigation strategies for addressing these public health challenges.

An Arylbenzofuran, Stilbene Dimers, and Prenylated Diels–Alder Adducts as Potent Diabetic Inhibitors from Morus bombycis Leaves

Morus bombycis has a long history of usage as a treatment for metabolic diseases, especially, diabetes mellitus (DM). Thus, we aimed to isolate and evaluate bioactive constituents derived from M. bombycis leaves for the treatment of DM. According to bioassay-guided isolation by column chromatography, eight compounds were obtained from M. bombycis leaves: two phenolic compounds, p-coumaric acid (1) and chlorogenic acid methyl ester (2), one stilbene, oxyresveratrol (3), two stilbene dimers, macrourin B (4) and austrafuran C (6), one 2-arylbenzofuran, moracin M (5), and two Diels–Alder type adducts, mulberrofuran F (7) and chalcomoracin (8). Among the eight isolated compounds, the anti-DM activity of 3–8 (which possess chemotaxonomic significance in Morus species) was evaluated by inhibition of α-glucosidase, protein tyrosine phosphatase 1B (PTP1B), human recombinant aldose reductase (HRAR), and advanced glycation end-product (AGE) formation as well as by scavenging peroxynitrite (ONOO−), which are crucial therapeutic targets of DM and its complications. Compounds 4 and 6–8 significantly inhibited α-glucosidase, PTP1B, and HRAR enzymes with mixed-type and non-competitive-type inhibition modes. Furthermore, the four compounds had low negative binding energies in both enzymes according to molecular docking simulation, and compounds 3–8 exhibited strong antioxidant capacity by inhibiting AGE formation and ONOO− scavenging. Overall results suggested that the most active stilbene-dimer-type compounds (4 and 6) along with Diels–Alder type adducts (7 and 8) could be promising therapeutic and preventive resources against DM and have the potential to be used as antioxidants, anti-diabetic agents, and anti-diabetic complication agents.

Relationship between Oxidative Stress and Left Ventricle Markers in Patients with Chronic Heart Failure

Oxidative stress is proposed in the literature as an important player in the development of CHF and correlates with left ventricle (LV) dysfunction and hypertrophy in the failing heart. In this study, we aimed to verify if the serum oxidative stress markers differ in chronic heart failure (CHF) patients' groups depending on the LV geometry and function. Patients were stratified into two groups according to left ventricular ejection fraction (LVEF) values: HFrEF (<40% (n = 27)) and HFpEF (≥40% (n = 33)). Additionally, patients were stratified into four groups according to LV geometry: NG-normal left ventricle geometry (n = 7), CR-concentric remodeling (n = 14), cLVH-concentric LV hypertrophy (n = 16), and eLVF-eccentric LV hypertrophy (n = 23). We measured protein (protein carbonyl (PC), nitrotyrosine (NT-Tyr), dityrosine), lipid (malondialdehyde (MDA), oxidizes (HDL) oxidation and antioxidant (catalase activity, total plasma antioxidant capacity (TAC) markers in serum. Transthoracic echocardiogram analysis and lipidogram were also performed. We found that oxidative (NT-Tyr, dityrosine, PC, MDA, oxHDL) and antioxidative (TAC, catalase) stress marker levels did not differ between the groups according to LVEF or LV geometry. NT-Tyr correlated with PC (r_s = 0.482, p = 0.000098), and oxHDL (r_s = 0.278, p = 0.0314). MDA correlated with total (r_s = 0.337, p = 0.008), LDL (r_s = 0.295, p = 0.022) and non-HDL (r_s = 0.301, p = 0.019) cholesterol. NT-Tyr negatively correlated with HDL cholesterol (r_s = -0.285, p = 0.027). LV parameters did not correlate with oxidative/antioxidative stress markers. Significant negative correlations were found between the end-diastolic volume of the LV and the end-systolic volume of the LV and HDL-cholesterol (r_s = -0.935, p < 0.0001; r_s = -0.906, p < 0.0001, respectively). Significant positive correlations between both the thickness of the interventricular septum and the thickness of the LV wall and the levels of triacylglycerol in serum (r_s = 0.346, p = 0.007; r_s = 0.329, p = 0.010, respectively) were found. In conclusions, we did not find a difference in serum concentrations of both oxidant (NT-Tyr, PC, MDA) and antioxidant (TAC and catalase) concentrations in CHF patients' groups according to LV function and geometry was found. The geometry of the LV could be related to lipid metabolism in CHF patients, and no correlation between oxidative/antioxidant and LV markers in CHF patients was found.

Combination Sodium Nitrite and Hydralazine Therapy Attenuates Heart Failure With Preserved Ejection Fraction Severity in a "2-Hit" Murine Model

Background Recent studies have suggested that cardiac nitrosative stress mediated by pathological overproduction of nitric oxide (NO) via inducible NO synthase (iNOS) contributes to the pathogenesis of heart failure with preserved ejection fraction (HFpEF). Other studies have suggested that endothelial NO synthase (eNOS) dysfunction and attenuated NO bioavailability contribute to HFpEF morbidity and mortality. We sought to further investigate dysregulated NO signaling and to examine the effects of a NO-based dual therapy (sodium nitrite+hydralazine) following the onset of HFpEF using a "2-hit" murine model. Methods and Results Nine-week-old male C57BL/6 N mice (n=15 per group) were treated concurrently with high-fat diet and N(ω)-nitro-L-arginine methyl ester (L-NAME) (0.5 g/L per day) via drinking water for 10 weeks. At week 5, mice were randomized into either vehicle (normal saline) or combination treatment with sodium nitrite (75 mg/L in the drinking water) and hydralazine (2.0 mg/kg IP, BID). Cardiac structure and function were monitored with echocardiography and invasive hemodynamic measurements. Cardiac mitochondrial respiration, aortic vascular function, and exercise performance were also evaluated. Circulating and myocardial nitrite were measured to determine the bioavailability of NO. Circulating markers of oxidative or nitrosative stress as well as systemic inflammation were also determined. Severe HFpEF was evident by significantly elevated E/E', LVEDP, and Tau in mice treated with L-NAME and HFD, which was associated with impaired NO bioavailability, mitochondrial respiration, aortic vascular function, and exercise capacity. Treatment with sodium nitrite and hydralazine restored NO bioavailability, reduced oxidative and nitrosative stress, preserved endothelial function and mitochondrial respiration, limited the fibrotic response, and improved exercise capacity, ultimately attenuating the severity of "two-hit" HFpEF. Conclusions Our data demonstrate that nitrite, a well-established biomarker of NO bioavailability and a physiological source of NO, is significantly reduced in the heart and circulation in the "2-hit" mouse HFpEF model. Furthermore, sodium nitrite+hydralazine combined therapy significantly attenuated the severity of HFpEF in the "2-hit" cardiometabolic HFpEF. These data suggest that supplementing NO-based therapeutics with a potent antioxidant and vasodilator agent may result in synergistic benefits for the treatment of HFpEF.

Valorisation of the Inhibitory Potential of Fresh and Dried Fruit Extracts of Prunus spinosa L. towards Carbohydrate Hydrolysing Enzymes, Protein Glycation, Multiple Oxidants and Oxidative Stress-Induced Changes in Human Plasma Constituents

Prunus spinosa fruits (sloes), both fresh and dried, are underexplored dietary components and ethno-phytotherapeutic remedies applied to treat chronic oxidative-stress-related diseases, including diabetes. The present study aimed to evaluate drying-related changes in the antidiabetic potential of sloe extracts and some bioactivity mechanisms, which might be connected with their traditional application. The polyphenol-enriched extracts, prepared by fractionated extraction and phytochemically standardised, i.a., by LC-MS/MS, were tested in vitro using a set of biological and chemical models. The experiments revealed the significant extracts' ability to counteract the generation of advanced glycation end products (AGEs) and inhibit the activity of key glycolytic enzymes, i.e., α-glucosidase and α-amylase. Moreover, they were proved to effectively scavenge multiple oxidants of physiological importance (O₂^•-, HO^•, H₂O₂, NO^•, HOCl), increase the non-enzymatic antioxidant capacity of human plasma (NEAC) under oxidative stress conditions induced by peroxynitrite, and protect plasma proteins and lipids against peroxidation and nitration at in vivo-relevant levels (1-50 µg/mL, equivalent to 0.03-6.32 µg polyphenols/mL). In most cases, the activity of fresh fruit extracts surpassed that of dried-based products. The correlation studies and tests on model compounds proved polyphenols as dominant contributors to the observed effects. Furthermore, the co-occurring representatives of various polyphenolic classes were found to contribute to the biological activity of sloes through additive and synergistic effects. Considering the extraction yield and activity parameters, especially the superior outcomes compared to anti-diabetic drugs aminoguanidine and acarbose in the anti-glycation and α-glucosidase inhibition tests, the methanol-water (75:25, v/v) extract of fresh fruits and its phenolic-enriched fractions revealed the most advantageous potential for functional application.

Traditional chinese medicine to prevent and treat diabetic erectile dysfunction

Diabetic erectile dysfunction (DED) is one of the most common complications of diabetes mellitus. However, current therapeutics have no satisfactory effect on DED. In recent years, traditional Chinese medicine (TCM) has shown good effects against DED. By now, several clinical trials have been conducted to study the effect of TCM in treating DED; yet, the underlying mechanism is not fully investigated. Therefore, in this review, we briefly summarized the pathophysiological mechanism of DED and reviewed the published clinical trials on the treatment of DED by TCM. Then, the therapeutic potential of TCM and the underlying mechanisms whereby TCM exerts protective effects were summarized. We concluded that TCM is more effective than chemical drugs in treating DED by targeting multiple signaling pathways, including those involved in oxidation, apoptosis, atherosclerosis, and endothelial function. However, the major limitation in the application of TCM against DED is the lack of a large-scale, multicenter, randomized, and controlled clinical trial on the therapeutic effect, and the underlying pharmaceutical mechanisms also need further investigation. Despite these limitations, clinical trials and further experimental studies will enhance our understanding of the mechanisms modulated by TCM and promote the widespread application of TCM to treat DED.

Recent Progress in Fluorescent Probes for Diabetes Visualization and Drug Therapy

Diabetes has become one of the most prevalent endocrine and metabolic diseases that threaten human health, and it is accompanied by serious complications. Therefore, it is vital and pressing to develop novel strategies or tools for prewarning and therapy of diabetes and its complications. Fluorescent probes have been widely applied in the detection of diabetes due to the fact of their attractive advantages. In this report, we comprehensively summarize the recent progress and development of fluorescent probes in detecting the changes in the various biomolecules in diabetes and its complications. We also discuss the design of fluorescent probes for monitoring diabetes in detail. We expect this review will provide new ideas for the development of fluorescent probes suitable for the prewarning and therapy of diabetes in future clinical transformation and application.

Modulation of Reactive Oxygen Species Homeostasis as a Pleiotropic Effect of Commonly Used Drugs

Age-associated diseases represent a growing burden for global health systems in our aging society. Consequently, we urgently need innovative strategies to counteract these pathological disturbances. Overwhelming generation of reactive oxygen species (ROS) is associated with age-related damage, leading to cellular dysfunction and, ultimately, diseases. However, low-dose ROS act as crucial signaling molecules and inducers of a vaccination-like response to boost antioxidant defense mechanisms, known as mitohormesis. Consequently, modulation of ROS homeostasis by nutrition, exercise, or pharmacological interventions is critical in aging. Numerous nutrients and approved drugs exhibit pleiotropic effects on ROS homeostasis. In the current review, we provide an overview of drugs affecting ROS generation and ROS detoxification and evaluate the potential of these effects to counteract the development and progression of age-related diseases. In case of inflammation-related dysfunctions, cardiovascular- and neurodegenerative diseases, it might be essential to strengthen antioxidant defense mechanisms in advance by low ROS level rises to boost the individual ROS defense mechanisms. In contrast, induction of overwhelming ROS production might be helpful to fight pathogens and kill cancer cells. While we outline the potential of ROS manipulation to counteract age-related dysfunction and diseases, we also raise the question about the proper intervention time and dosage.

Non-Traditional Pathways for Platelet Pathophysiology in Diabetes: Implications for Future Therapeutic Targets

Cardiovascular complications remain the leading cause of morbidity and mortality in individuals with diabetes, driven by interlinked metabolic, inflammatory, and thrombotic changes. Hyperglycaemia, insulin resistance/deficiency, dyslipidaemia, and associated oxidative stress have been linked to abnormal platelet function leading to hyperactivity, and thus increasing vascular thrombotic risk. However, emerging evidence suggests platelets also contribute to low-grade inflammation and additionally possess the ability to interact with circulating immune cells, further driving vascular thrombo-inflammatory pathways. This narrative review highlights the role of platelets in inflammatory and immune processes beyond typical thrombotic effects and the impact these mechanisms have on cardiovascular disease in diabetes. We discuss pathways for platelet-induced inflammation and how platelet reprogramming in diabetes contributes to the high cardiovascular risk that characterises this population. Fully understanding the mechanistic pathways for platelet-induced vascular pathology will allow for the development of more effective management strategies that deal with the causes rather than the consequences of platelet function abnormalities in diabetes.

Nitrotyrosine, Nitrated Lipoproteins, and Cardiovascular Dysfunction in Patients with Type 2 Diabetes: What Do We Know and What Remains to Be Explained?

Diabetes mellitus (DM) is a strong risk factor for the development of cardiovascular diseases (CVDs), which are the most important cause of morbidity and mortality in the population of patients living with DM. DM is associated with lipid metabolism disorders characterized by a decrease in the high-density lipoprotein blood concentration, an increase in the triglyceride blood concentration, and the presence of modified lipoproteins not routinely measured in clinical practice. Nitrated lipoproteins are produced by the nitration of the tyrosyl residues of apolipoproteins by myeloperoxidase. There is some evidence from the research conducted showing that nitrated lipoproteins may play a role in the development of cardiovascular dysfunction, but this issue requires further investigation. It was found that the nitration of HDL particles was associated with a decrease in caspase-3 and paraoxonase-1 activity, as well as a decrease in the activity of cholesterol transport via ABCA1, which reduces the protective effect of HDL particles on the cardiovascular system. Less information has been collected about the role of nitrated LDL particles. Thus far, much more information has been obtained on the relationship of nitrotyrosine expression with the presence of cardiovascular risk factors and the development of cardiovascular dysfunction. The purpose of this paper is to provide an extensive review of the literature and to present the most important information on the current state of knowledge on the association between nitrotyrosine and nitrated lipoproteins with dysfunction of the cardiovascular system, especially in patients living with DM. Moreover, directions for future research in this area were discussed.

NiONP-Induced Oxidative Stress and Mitochondrial Impairment in an In Vitro Pulmonary Vascular Cell Model Mimicking Endothelial Dysfunction

The development and use of nanomaterials, especially of nickel oxide nanoparticles (NiONPs), is expected to provide many benefits but also has raised concerns about the potential human health risks. Inhaled NPs are known to exert deleterious cardiovascular side effects, including pulmonary hypertension. Consequently, patients with pulmonary hypertension (PH) could be at increased risk for morbidity. The objective of this study was to compare the toxic effects of NiONPs on human pulmonary artery endothelial cells (HPAEC) under physiological and pathological conditions. The study was conducted with an in vitro model mimicking the endothelial dysfunction observed in PH. HPAEC were cultured under physiological (static and normoxic) or pathological (20% cycle stretch and hypoxia) conditions and exposed to NiONPs (0.5–5 μg/cm²) for 4 or 24 h. The following endpoints were studied: (i) ROS production using CM-H₂DCF-DA and MitoSOX probes, (ii) nitrite production by the Griess reaction, (iii) IL-6 secretion by ELISA, (iv) calcium signaling with a Fluo-4 AM probe, and (v) mitochondrial dysfunction with TMRM and MitoTracker probes. Our results evidenced that under pathological conditions, ROS and nitrite production, IL-6 secretions, calcium signaling, and mitochondria alterations increased compared to physiological conditions. Human exposure to NiONPs may be associated with adverse effects in vulnerable populations with cardiovascular risks.

Cannabinoid receptor 2 activation alleviates diabetes-induced cardiac dysfunction, inflammation, oxidative stress, and fibrosis

Diabetes mellitus promotes accelerated cardiovascular aging and inflammation, which in turn facilitate the development of cardiomyopathy/heart failure. High glucose-induced oxidative/nitrative stress, activation of various pro-inflammatory, and cell death pathways are critical in the initiation and progression of the changes culminating in diabetic cardiomyopathy. Cannabinoid 2 receptor (CB₂R) activation in inflammatory cells and activated endothelium attenuates the pathological changes associated with atherosclerosis, myocardial infarction, stroke, and hepatic cardiomyopathy. In this study, we explored the role of CB₂R signaling in myocardial dysfunction, oxidative/nitrative stress, inflammation, cell death, remodeling, and fibrosis associated with diabetic cardiomyopathy in type 1 diabetic mice. Control human heart left ventricles and atrial appendages, similarly to mouse hearts, had negligible CB₂R expression determine by RNA sequencing or real-time RT-PCR. Diabetic cardiomyopathy was characterized by impaired diastolic and systolic cardiac function, enhanced myocardial CB₂R expression, oxidative/nitrative stress, and pro-inflammatory response (tumor necrosis factor-α, interleukin-1β, intracellular adhesion molecule 1, macrophage inflammatory protein-1, monocyte chemoattractant protein-1), macrophage infiltration, fibrosis, and cell death. Pharmacological activation of CB₂R with a selective agonist attenuated diabetes-induced inflammation, oxidative/nitrative stress, fibrosis and cell demise, and consequent cardiac dysfunction without affecting hyperglycemia. In contrast, genetic deletion of CB₂R aggravated myocardial pathology. Thus, selective activation of CB₂R ameliorates diabetes-induced myocardial tissue injury and preserves the functional contractile capacity of the myocardium in the diabetic milieu. This is particularly encouraging, since unlike CB₁R agonists, CB₂R agonists do not elicit psychoactive activity and cardiovascular side effects and are potential clinical candidates in the treatment of diabetic cardiovascular and other complications.

The Effects of Sorbus aucuparia L. Fruit Extracts on Oxidative/Nitrative Modifications of Human Fibrinogen, Impact on Enzymatic Properties of Thrombin, and Hyaluronidase Activity In Vitro

Sorbus aucuparia L. fruits (rowanberries) are food products with acknowledged nutritional value, high phenolic content, and traditional application in diabetes. In this study, the effects of rowanberry extracts (phytochemically standardised, i.a., by LC-MS/MS) on some aspects of plasma haemostasis and vascular conditions were evaluated in vitro as possible mechanisms connected with cardiovascular complications of diabetes. The analyses of structural modifications of human fibrinogen under oxidative stress conditions (C-ELISA, SDS-PAGE and Western blot) revealed that the extracts (at a concentration of 1-5 µg/mL) considerably reduced the nitration of tyrosine residues and formation of high-molecular-weight aggregates. Moreover, they inhibited the enzymatic activity of thrombin (both amidolytic and proteolytic). Additionally, some promising outcomes might be expected regarding endothelial functions from the extracts ability to inhibit hyaluronidase. Parallel experiments on model polyphenols and correlation studies formed the basis for determining the contribution of different compounds, including hydroxycinnamic acid derivatives, flavonols, and low- or high-molecular-weight flavan-3-ols derivatives (proanthocyanidins), to the observed effects. The possible synergistic activity of individual constituents was also noticed. These results broaden the knowledge on the biological activity of rowanberries, partly confirming their health-promoting properties, and indicating that their functional applications might be promising.

Two New Isoprenoid Flavonoids from Sophora flavescens with Antioxidant and Cytotoxic Activities

Sophora flavescens is a regularly used traditional Chinese medicine. In an attempt to discover adequate active agents, the isoprenoid flavonoids from S. flavescens were further investigated. In this work, two new compounds (1-2, kurarinol A-B) together with 26 known ones (3-28) were isolated and elucidated on the basis of extensive NMR, UV and MS analyses. Furthermore, the antioxidant activity of all constituents was assessed through ABTS, PTIO and DPPH methodologies and also were evaluated for cytotoxic activity by three tumor cell lines (HepG2, A549 and MCF7) and one human normal cell line (LO2 cells). As a result, a multitude of components revealed significant inhibitory activity. In particular, compound 1-2 (kurarinol A-B), two new flavanonols derivatives, exhibited the most potent ABTS inhibitory activity with IC50 of 1.21 µg/mL and 1.81 µg/mL, respectively. Meanwhile, the new compound 1 demonstrated remarkable cytotoxicity against three cancer cells lines with IC50 values ranging from 7.50-10.55 μM but showed little effect on the normal cell. The two new isoprenoid flavonoids could be promising antioxidant and anti-tumor nature agents.

GNP-CeO2- polyaniline hybrid hydrogel for electrochemical detection of peroxynitrite anion and its integration in a microfluidic platform

Peroxynitrite anion (ONOO^-) is an important in vivo oxidative stress biomarker whose aberrant levels have pathophysiological implications. In this study, an electrochemical sensor for ONOO^- detection was developed based on graphene nanoplatelets-cerium oxide nanocomposite (GNP-CeO₂) incorporated polyaniline (PANI) conducting hydrogels. The nanocomposite-hydrogel platform exhibited distinct synergistic advantages in terms of large electroactive surface coverage and providing a conductive pathway for electron transfer. Besides, the 3D porous structure of hydrogel integrated the GNP-CeO₂ nanocomposite to provide hybrid materials for the evolution of catalytic activity towards electrochemical oxidation of ONOO^-. Various microscopic and spectroscopic characterization techniques endorsed the successful formation of GNP-CeO₂-PANI hydrogel. Cyclic voltammetry (CV) measurements of GNP-CeO₂-PANI hydrogel modified screen-printed electrodes (SPE) were carried out to record the current changes influenced by ONOO^-. The prepared sensor demonstrated a significant dose-dependent increase in CV peak current within a linear range of 5-100 µM (at a potential of 1.12 V), and a detection limit of 0.14 with a sensitivity of 29.35 ± 1.4 μA μM^-1. Further, a customized microfluidic flow system was integrated with the GNP-CeO₂-PANI hydrogel modified SPE to enable continuous electrochemical detection of ONOO^- at low sample volumes. The developed microfluidic electrochemical device demonstrated an excellent sensitivity towards ONOO^- under optimal experimental conditions. Overall, the fabricated microfluidic device with hybrid hydrogels as electrochemical interfaces provides a reliable assessment of ONOO^- levels. This work offers considerable potential for understanding the oxidative stress-related disease mechanisms through determination of ONOO^- in biological samples.

Bio-inspired nitrogen oxide (NOx) interconversion reactivities of synthetic heme Compound-I and Compound-II intermediates

Dioxygen activating heme enzymes have long predicted to be powerhouses for nitrogen oxide interconversion, especially for nitric oxide (NO) oxidation which has far-reaching biological and/or environmental impacts. Lending credence, reactivity of NO with high-valent heme‑oxygen intermediates of globin proteins has recently been implicated in the regulation of a variety of pivotal physiological events such as modulating catalytic activities of various heme enzymes, enhancing antioxidant activity to inhibit oxidative damage, controlling inflammatory and infectious properties within the local heme environments, and NO scavenging. To reveal insights into such crucial biological processes, we have investigated low temperature NO reactivities of two classes of synthetic high-valent heme intermediates, Compound-II and Compound-I. In that, Compound-II rapidly reacts with NO yielding the six-coordinate (NO bound) heme ferric nitrite complex, which upon warming to room temperature converts into the five-coordinate heme ferric nitrite species. These ferric nitrite complexes mediate efficient substrate oxidation reactions liberating NO; i.e., shuttling NO₂^- back to NO. In contrast, Compound-I and NO proceed through an oxygen-atom transfer process generating the strong nitrating agent NO₂, along with the corresponding ferric nitrosyl species that converts to the naked heme ferric parent complex upon warmup. All reaction components have been fully characterized by UV-vis, ²H NMR and EPR spectroscopic methods, mass spectrometry, elemental analyses, and semi-quantitative determination of NO₂^- anions. The clean, efficient, potentially catalytic NO_x interconversions driven by high-valent heme species presented herein illustrate the strong prospects of a heme enzyme/O₂/NO_x dependent unexplored territory that is central to human physiology, pathology, and therapeutics.

Vascular growth factors as potential new treatment in cardiorenal syndrome in diabetes

BACKGROUND

Cardiorenal syndrome in diabetes is characterised by alterations of the cardiovascular system paralleled by kidney disease with progressive renal function decline. In diabetes, chronic metabolic and haemodynamic perturbations drive endothelial dysfunction, inflammation, oxidative stress and progressive tissue fibrosis which, in turn, lead to heart and renal anatomo-functional damage. In physiology, vascular growth factors have been implicated in vascular homeostasis; their imbalance, in disease setting such as diabetes, leads to vascular dysfunction and cardiorenal damage.

AIMS

To define the role of vascular growth factors and angiopoietins in cardiorenal syndrome.

MATERIAL AND METHODS

We will focus on the two most studied vascular growth factors, vascular endothelial growth factor (VEGF) and angiopoietins (Angpt). The balance and crosstalk between these growth factors are important in organ development and in the maintenance of a healthy vasculature, heart and kidney. The observed alterations in expression/function of these vascular growth factors, as seen in diabetes, are a protective response against external perturbations.

RESULTS

The chronic insults driving diabetes-mediated cardiorenal damage results in a paradoxical situation, whereby the vascular growth factors imbalance becomes a mechanism of disease. Studies have explored the possibility of modulating the expression/action of vascular growth factors to improve disease outcome. Experimental work has been conducted in animals and has been gradually translated in humans.

DISCUSSION

Difficulties have been encountered especially when considering the magnitude, timing and duration of interventions targeting a selective vascular growth factor. Targeting VEGF in cardiovascular disease has been challenging, while modulation of the Angpt system seems more promising.

CONCLUSION

Future studies will establish the translatability of therapies targeting vascular growth factors for heart and kidney disease in patients with diabetes.

PARPs in lipid metabolism and related diseases

PARPs and tankyrases (TNKS) represent a family of 17 proteins. PARPs and tankyrases were originally identified as DNA repair factors, nevertheless, recent advances have shed light on their role in lipid metabolism. To date, PARP1, PARP2, PARP3, tankyrases, PARP9, PARP10, PARP14 were reported to have multi-pronged connections to lipid metabolism. The activity of PARP enzymes is fine-tuned by a set of cholesterol-based compounds as oxidized cholesterol derivatives, steroid hormones or bile acids. In turn, PARPs modulate several key processes of lipid homeostasis (lipotoxicity, fatty acid and steroid biosynthesis, lipoprotein homeostasis, fatty acid oxidation, etc.). PARPs are also cofactors of lipid-responsive nuclear receptors and transcription factors through which PARPs regulate lipid metabolism and lipid homeostasis. PARP activation often represents a disruptive signal to (lipid) metabolism, and PARP-dependent changes to lipid metabolism have pathophysiological role in the development of hyperlipidemia, obesity, alcoholic and non-alcoholic fatty liver disease, type II diabetes and its complications, atherosclerosis, cardiovascular aging and skin pathologies, just to name a few. In this synopsis we will review the evidence supporting the beneficial effects of pharmacological PARP inhibitors in these diseases/pathologies and propose repurposing PARP inhibitors already available for the treatment of various malignancies.

Novel insight into biological activity and phytochemical composition of Sorbus aucuparia L. fruits: Fractionated extracts as inhibitors of protein glycation and oxidative/nitrative damage of human plasma components

Sorbus aucuparia L. is a source of edible fruits appreciated for their nutritional and medicinal properties. In this work some bioactivity mechanisms were evaluated, which might be connected with the traditional application of rowanberries in cardiovascular complications of diabetes. With the use of a panel of chemical and biological in vitro models the rowanberry extracts were proved to significantly inhibit the formation of advanced glycation end products, neutralise multiple oxidants generated in vivo, increase the non-enzymatic antioxidant capacity of human plasma and protect plasma components (proteins and lipids) against oxidative/nitrative damage at in vivo-relevant levels (1-5 µg/mL). Moreover, the extracts were found safe in cytotoxicity tests on the peripheral blood mononuclear cells. The comprehensive phytochemical profiling of the extracts (RP/HILIC-UHPLC-PDA-ESI-MS³, HPLC-PDA, and UV-spectrophotometric methods) led to the identification of 51 phenolics, including caffeic and ferulic acids pseudodepsides (34 compounds, prevailing isomers of chlorogenic acid and cynarin, total content up to 269.4 mg/g), flavonols (mostly quercetin glycosides, up to 5.8 mg/g), flavan-3-ol derivatives (proanthocyanidin oligomers and polymers, up to 17.0 mg/g), and simple phenolic acids. The experiments on model constituents of the extracts and correlation studies were used to evaluate contribution of polyphenols to the observed effects. Taking into account the possible additive and synergistic effects, the co-occurrence of various compounds was indicated as partly responsible for biological activity of the fruits. Considering both the composition and activity parameters, the methanol-water (1:1, v/v) extract and its concentrated phenolic fractions appeared to be the most advantageous for biological application.

Parenteral Nutrition and Cardiotoxicity

Parenteral nutrition (PN) is a life-saving nutritional therapy for those situations when patients are unable to receive enteral nutrition. However, despite a multitude of benefits offered by PN, it is associated with a variety of side effects, most notably parenteral nutrition-associated liver disease (PNALD). Adverse effects of PN on other organ systems, such as brain and cardiovascular system, have been poorly studied. There have been several case reports, studies, and a recent animal study highlighting cardiotoxic effects of PN; however, much remains unclear about the underlying mechanisms causing cardiac damage. In this review, we propose a series of potential mechanisms behind PN-associated heart injury, and we provide an overview of therapeutic strategies and recent scientific advances.

Plant Compounds for the Treatment of Diabetes, a Metabolic Disorder: NF-κB as a Therapeutic Target

Background:

The prevalence of diabetes in the world population hás reached 8.8 % and is expected to rise to 10.4% by 2040. Hence, there is an urgent need for the discovery of drugs against therapeutic targets to sojourn its prevalence. Previous studies proved that NF-κB serves as a central agent in the development of diabetic complications.

Objectives:

This review intended to list the natural plant compounds that would act as inhibitors of NF-κB signalling in different organs under the diabetic condition with their possible mechanism of action.

Methods:

Information on NF-κB, diabetes, natural products, and relation in between them, was gathered from scientific literature databases such as Pubmed, Medline, Google scholar, Science Direct, Springer, Wiley online library.

Results and Conclusion:

NF-κB plays a crucial role in the development of diabetic complications because of its link in the expression of genes that are responsible for organs damage such as kidney, brain, eye, liver, heart, muscle, endothelium, adipose tissue and pancreas by inflammation, apoptosis and oxidative stress. Activation of PPAR-α, SIRT3/1, and FXR through many cascades by plant compounds such as terpenoids, iridoids, flavonoids, alkaloids, phenols, tannins, carbohydrates, and phytocannabinoids recovers diabetic complications. These compounds also exhibit the prevention of NF-κB translocation into the nucleus by inhibiting NF-κB activators, such as VEGFR, RAGE and TLR4 receptors, which in turn, prevent the activation of many genes involved in tissue damage. Current knowledge on the treatment of diabetes by targeting NF-κB is limited, so future studies would enlighten accordingly.

Reduction of peroxynitrite by some manganoporphyrins of AEOL series: DFT approach with dispersion correction and NBO analysis

The AEOL series of manganoporphyrins (MnP; AEOL compounds were named by US Aeolus pharmaceuticals) designed as superoxide dismutase mimic are well-known for their powerful catalytic activity to neutralize reactive oxygen and nitrogen species. Reductive oxygen atom cleavage from peroxynitrite (ONOO^-) to form NO₂ in aqueous solution by some AEOL compounds (AEOL-10113, AEOL-10150, AEOL-11114 and AEOL-11203) was studied by DFT/M06-2X computations with D3 dispersion correction and gCP (geometrical counterpoise correction) for basis set superposition error. DFT computation showed that AEOL-10150 can form the most stable association complex {MnP^…OONO} among four AEOL models. AEOL-10150 complex with ONOO^- has the lowest deformation energy. In AEOL compounds and their association complexes with ONOO^-, Mn atom prefered the high spin state (S = 2) to the intermediate spin state (S = 1). Natural bond orbital analysis showed that electron transfer from the most negative oxygen atom in ONOO^- to Mn atom in MnP has the biggest interaction energy among all kinds of donor-acceptor interactions between ONOO^- and MnP.

Biomolecules and Electrochemical Tools in Chronic Non-Communicable Disease Surveillance: A Systematic Review

Over recent three decades, the electrochemical techniques have become widely used in biological identification and detection, because it presents optimum features for efficient and sensitive molecular detection of organic compounds, being able to trace quantities with a minimum of reagents and sample manipulation. Given these special features, electrochemical techniques are regularly exploited in disease diagnosis and monitoring. Specifically, amperometric electrochemical analysis has proven to be quite suitable for the detection of physiological biomarkers in monitoring health conditions, as well as toward the control of reactive oxygen species released in the course of oxidative burst during inflammatory events. Besides, electrochemical detection techniques involve a simple and swift assessment that provides a low detection-limit for most of the molecules enclosed biological fluids and related to non-transmittable morbidities.

Anticancer Therapy-Related Increases in Arterial Stiffness: A Systematic Review and Meta-Analysis

Background

Cardio‐oncology is a clinical discipline focused primarily on the early detection of anticancer therapy–related cardiomyopathy. However, there is growing evidence that the direct adverse consequences extend beyond the myocardium to affect the vasculature, but this evidence remains limited. In addition, there remains a paucity of clinically based strategies for monitoring vascular toxicity in these patients. Importantly, arterial stiffness is increasingly recognized as a surrogate end point for cardiovascular disease and may be an important vascular outcome to consider. Therefore, the aim of this systematic review and meta‐analysis was to summarize evidence of increased arterial stiffening with anticancer therapy and evaluate the effect of treatment modifiers.

Methods and Results

A total of 19 longitudinal and cross‐sectional studies that evaluated arterial stiffness both during and following anticancer therapy were identified using multiple databases. Two separate analyses were performed: baseline to follow‐up (12 studies) and control versus patient groups (10 studies). Subgroup analysis evaluated whether stiffness differed as a function of treatment type and follow‐up time. Standard mean differences and mean differences were calculated using random effect models. Significant increases in arterial stiffness were identified from baseline to follow‐up (standard mean difference, 0.890; 95% CI, 0.448–1.332; P<0.0001; mean difference, 1.505; 95% CI, 0.789–2.221; P≤0.0001) and in patient versus control groups (standard mean difference, 0.860; 95% CI, 0.402–1.318; P=0.0002; mean difference, 1.437; 95% CI, 0.426–2.448; P=0.0052). Subgroup analysis indicated differences in arterial stiffness between anthracycline‐based and non‐anthracycline‐based therapies (standard mean difference, 0.20; 95% CI, 0.001–0.41; P=0.048), but not follow‐up time.

Conclusions

Significant arterial stiffening occurs following anticancer therapy. Our findings support the use of arterial stiffness as part of a targeted vascular imaging strategy for the identification of early cardiovascular injury during treatment and for the detection of long‐term cardiovascular injury into survivorship.

Synthetic melanin nanoparticles as peroxynitrite scavengers, photothermal anticancer and heavy metals removal platforms

Melanin is a ubiquitous natural polyphenolic pigment with versatile applications including physiological functions. This polymeric material is found in a diversity of living organisms from bacteria to mammals. The biocompatibility and thermal stability of melanin nanoparticles make them good candidates to work as free radical scavengers and photothermal anticancer substrates. Research studies have identified melanin as an antioxidative therapeutic agent and/or reactive oxygen species (ROS) scavenger that includes neutralization of peroxynitrite. In addition, melanin nanoparticles have emerged as an anticancer photothermal platform that has the capability to kill cancer cells. Recently, melanin nanoparticles have been successfully used as chelating agents to purify water from heavy metals, such as hexavalent chromium. This review article highlights some selected aspects of cutting-edge melanin applications. Herein, we will refer to the recent literature that addresses melanin nanoparticles and its useful physicochemical properties as a hot topic in biomaterial science. It is expected that the techniques of Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), and time-resolved Electron Paramagnetic Resonance (EPR) will have a strong impact on the full characterization of melanin nanoparticles and the subsequent exploration of their physiological and chemical mechanisms.

The role of ADP-ribose metabolism in metabolic regulation, adipose tissue differentiation, and metabolism

In this review, Szanto et al. summarize the metabolic regulatory roles of PARP enzymes and their associated pathologies.

Poly(ADP-ribose) polymerases (PARPs or ARTDs), originally described as DNA repair factors, have metabolic regulatory roles. PARP1, PARP2, PARP7, PARP10, and PARP14 regulate central and peripheral carbohydrate and lipid metabolism and often channel pathological disruptive metabolic signals. PARP1 and PARP2 are crucial for adipocyte differentiation, including the commitment toward white, brown, or beige adipose tissue lineages, as well as the regulation of lipid accumulation. Through regulating adipocyte function and organismal energy balance, PARPs play a role in obesity and the consequences of obesity. These findings can be translated into humans, as evidenced by studies on identical twins and SNPs affecting PARP activity.

Zinc supplementation protects against diabetic endothelial dysfunction via GTP cyclohydrolase 1 restoration

This study explored whether zinc supplementation alleviates diabetic endothelial dysfunction and the possible mechanisms underlying. We found that high glucose exposure significantly increased reactive oxygen species (ROS) and decreased guanosine 5'-triphosphate cyclohydrolase 1 (GTPCH1) and tetrahydrobiopterin (BH4) levels in bovine aortic endothelial cells (BAECs) in a time-dependent manner. High glucose increased zinc release from GTPCH1 in a similar trend. Zinc supplementation restored GTPCH1 and BH4 levels and blocked ROS accumulation in both BACEs and wild type GTPCH1 transfected HEK293 cells, but not in the zinc-free C141R mutant of GTPCH1 transfected ones. In vivo experiments showed that exogenous supplementation of zinc to streptozotocin (STZ)-induced diabetic mice partially improved the impaired maximal endothelium-dependent vasorelaxation, reversed the aberrant reduction of GTPCH1 and BH4, and suppressed the elevation of ROS in the aortas. In conclusion, our study demonstrated a novel mechanism that via GTPCH1 restoration zinc supplementation exerts a protective benefit on diabetic endothelial dysfunction.

MicroRNA-199a-3p and MicroRNA-199a-5p Take Part to a Redundant Network of Regulation of the NOS (NO Synthase)/NO Pathway in the Endothelium

Objective- Members of the microRNA (miR)-199a family, namely miR-199a-5p and miR-199a-3p, have been recently identified as potential regulators of cardiac homeostasis. Also, upregulation of miR-199a expression in cardiomyocytes was reported to influence endothelial cells. Whether miR-199a is expressed by endothelial cells and, if so, whether it directly regulates endothelial function remains unknown. We investigate the implication of miR-199a products on endothelial function by focusing on the NOS (nitric oxide synthase)/NO pathway. Approach and Results- Bovine aortic endothelial cells were transfected with specific miRNA inhibitors (locked-nucleic acids), and potential molecular targets identified with prediction algorithms were evaluated by Western blot or immunofluorescence. Ex vivo experiments were performed with mice treated with antagomiRs targeting miR-199a-3p or -5p. Isolated vessels and blood were used for electron paramagnetic resonance or myograph experiments. eNOS (endothelial NO synthase) activity (through phosphorylations Ser1177/Thr495) is increased by miR-199a-3p/-5p inhibition through an upregulation of the PI3K (phosphoinositide 3-kinase)/Akt (protein kinase B) and calcineurin pathways. SOD1 (superoxide dismutase 1) and PRDX1 (peroxiredoxin 1) upregulation was also observed in locked-nucleic acid-treated cells. Moreover, miR-199a-5p controls angiogenesis and VEGFA (vascular endothelial growth factor A) production and upregulation of NO-dependent relaxation were observed in vessels from antagomiR-treated mice. This was correlated with increased circulated hemoglobin-NO levels and decreased superoxide production. Angiotensin infusion for 2 weeks also revealed an upregulation of miR-199a-3p/-5p in vascular tissues. Conclusions- Our study reveals that miR-199a-3p and miR-199a-5p participate in a redundant network of regulation of the NOS/NO pathway in the endothelium. We highlighted that inhibition of miR-199a-3p and -5p independently increases NO bioavailability by promoting eNOS activity and reducing its degradation, thereby supporting VEGF-induced endothelial tubulogenesis and modulating vessel contractile tone.

Arrhythmogenic Substrates for Atrial Fibrillation in Obesity

Global obesity rates have nearly tripled since 1975. This obesity rate increase is mirrored by increases in atrial fibrillation (AF) that now impacts nearly 10% of Americans over the age of 65. Numerous epidemiologic studies have linked incidence of AF and obesity and other obesity-related diseases, including hypertension and diabetes. Due to the wealth of epidemiologic data linking AF with obesity-related disease, mechanisms of AF pathogenesis in the context of obesity are an area of ongoing investigation. However, progress has been somewhat slowed by the complex phenotype of obesity; separating the effects of obesity from those of related sequelae is problematic. While the initiation of pathogenic pathways leading to AF varies with disease (including increased glycosylation in diabetes, increased renin angiotensin aldosterone system activation in hypertension, atrial ischemia in coronary artery disease, and sleep apnea) the pathogenesis of AF is united by shared mediators of altered conduction in the atria. We suggest focusing on these downstream mediators of AF in obesity is likely to yield more broadly applicable data. In the context of obesity, AF is driven by the interrelated processes of inflammation, atrial remodeling, and oxidative stress. Obesity is characterized by a constant low-grade inflammation that leads to increased expression of pro-inflammatory cytokines. These cytokines contribute to changes in cardiomyocyte excitability. Atrial structural remodeling, including fibrosis, enlargement, and fatty infiltration is a prominent feature of AF and contributes to the altered conduction. Finally, obesity impacts oxidative stress. Within the cardiomyocyte, oxidative stress is increased through both increased production of reactive oxygen species and by downregulation of scavenging enzymes. This increased oxidative stress modulates of cardiomyocyte excitability, increasing susceptibility to AF. Although the initiating insults vary, inflammation, atrial remodeling, and oxidative stress are conserved mechanisms in the pathophysiology of AF in the obese patients. In this review, we highlight mechanisms that have been shown to be relevant in the pathogenesis of AF across obesity-related disease.

Impaired glutathione-related antioxidant defenses in the arterial tissue of diabetic patients

We studied the specific enzymatic activities of selenium-dependent (GSH-Px) and -independent (GST-Px) glutathione peroxidase, glutathione reductase (GSSG-Red), and glutathione S-transferase (GST) in internal mammary arteries (IMArt) specimens obtained during coronary artery bypass surgery in 18 patients with type 2 diabetes mellitus as compared to 18 non-diabetic controls; vascular lipid peroxidation, namely fluorescent damage products of lipid peroxidation (FDPL) as 4-hydroxynonenal-related oxidative stress indicators, was also studied. Moreover, in other 16 diabetic patients and 16 controls, total glutathione (TGlut) was determined in IMArt specimens specifically homogenized in sulfosalycilic acid to prevent vascular GSH depletion. The activities of GSH-Px, GSSG-Red, and GST were significantly lower, and FDPL levels higher, in the arterial tissue of diabetic patients than in that of controls; GST-Px was undetectable. Such enzymatic activities were inversely correlated with vascular lipid peroxidation, highlighting their antioxidant role in the arterial tissue, as were HbA1c and FDPL levels with the enzymatic activities, suggesting that glycation, oxidant species and lipoperoxidation aldehydes may be involved in glutathione-related enzyme inactivation. Further, in the diabetic patients HbA1c was correlated directly with lipid peroxidation but inversely with TGlut of the arterial tissue. In the patients considered for vascular enzymatic activities and FDPL assay, 3/4-vessel coronary artery disease (CAD) as expression of atherosclerosis severity was present in 9 diabetic patients and in 3 controls. Notably, vascular glutathione-related enzymatic activities were significantly lower, and FDPL levels higher, in the 9 diabetic patients with 3/4-vessel CAD than in the 9 without, as well as in the total of 12 patients with 3/4-vessel CAD than in the total of 24 patients without. Moreover, vascular TGlut content was significantly lower in the diabetic than in the control patients. Three/4-vessel CAD was present in 6 diabetic patients and in 2 controls considered for determination of vascular Tglut content, which was significantly lower in the diabetic patients with 3/4-vessel CAD than in those without, as well in the total of 8 patients with 3/4-vessel CAD than in the total of 24 patients without. Thus, weakened glutathione-related antioxidant capacity and oxidative stress of the arterial tissue are associated with the severity of atherosclerosis. In conclusion, impaired glutathione-related antioxidant defenses of the arterial tissue occur in diabetic patients, eventually favoring vascular oxidative stress and the severity of atherosclerosis.

Chronic Kidney Disease and Disproportionally Increased Cardiovascular Damage: Does Oxidative Stress Explain the Burden?

Chronic kidney disease (CKD) patients are among the groups at the highest risk for cardiovascular disease and significantly shortened remaining lifespan. CKD enhances oxidative stress in the organism with ensuing cardiovascular damage. Oxidative stress in uremia is the consequence of higher reactive oxygen species (ROS) production, whereas attenuated clearance of pro-oxidant substances and impaired antioxidant defenses play a complementary role. The pathophysiological mechanism underlying the increased ROS production in CKD is at least partly mediated by upregulation of the intrarenal angiotensin system. Enhanced oxidative stress in the setting of the uremic milieu promotes enzymatic modification of circulating lipids and lipoproteins, protein carbamylation, endothelial dysfunction via disruption of nitric oxide (NO) pathways, and activation of inflammation, thus accelerating atherosclerosis. Left ventricular hypertrophy (LVH) and heart failure are hallmarks of CKD. NADPH oxidase activation, xanthine oxidase, mitochondrial dysfunction, and NO-ROS are the main oxidative pathways leading to LVH and the cardiorenal syndrome. Finally, a subset of antioxidant enzymes, the paraoxonases (PON), deserves special attention due to abundant clinical evidence accumulated regarding reduced serum PON1 activity in CKD as a contributor to the increased burden of cardiovascular disease. Future, meticulously designed studies are needed to assess the effects of antioxidant therapy on patients with CKD.

Divergent roles of endothelial nitric oxide synthases system in maintaining cardiovascular homeostasis

Accumulating evidence has demonstrated the importance of reactive oxygen species (ROS) as an essential second messenger in health and disease. Endothelial dysfunction is the hallmark of atherosclerotic cardiovascular diseases, in which pathological levels of ROS are substantially involved. The endothelium plays a crucial role in modulating tone of underlying vascular smooth muscle by synthesizing and releasing nitric oxide (NO) and endothelium-dependent hyperpolarization (EDH) factors in a distinct vessel size-dependent manner through the diverse roles of the endothelial NO synthases (NOSs) system. Endothelium-derived hydrogen peroxide (H₂O₂) is a physiological signaling molecule serving as one of the major EDH factors especially in microcirculations and has gained increasing attention in view of its emerging relevance for cardiovascular homeostasis. In the clinical settings, it has been reported that antioxidant supplements are unexpectedly ineffective to prevent cardiovascular events. These lines of evidence indicate the potential importance of the physiological balance between NO and H₂O₂/EDH through the diverse functions of endothelial NOSs system in maintaining cardiovascular homeostasis. A better understanding of cardiovascular redox signaling is certainly needed to develop novel therapeutic strategies in cardiovascular medicine. In this review, we will briefly summarize the current knowledge on the emerging regulatory roles of redox signaling pathways in cardiovascular homeostasis, with particular focus on the two endothelial NOSs-derived mediators, NO and H₂O₂/EDH.

The structural damages of lens crystallins induced by peroxynitrite and methylglyoxal, two causative players in diabetic complications and preventive role of lens antioxidant components

Peroxynitrite (PON) and methylglyoxal (MGO), two diabetes-associated compounds, are believed to be important causative players in development of diabetic cataracts. In the current study, different spectroscopic methods, gel electrophoresis, lens culture and microscopic assessments were applied to examine the impact of individual, subsequent or simultaneous modification of lens crystallins with MGO and PON on their structure, oligomerization and aggregation. The protein modifications were confirmed with detection of the significantly increased quantity of carbonyl groups and decreased levels of sulfhydryl, tyrosine and tryptophan. Also, lens proteins modification with these chemical agents was accompanied with important structural alteration, oligomerization, disulfide/chromophore mediated protein crosslinking and important proteolytic instability. All these structural damages were more pronounced when the lens proteins were modified in the presence of both mentioned chemical agents, either in sequential or simultaneous manner. Ascorbic acid and glutathione, as the main components of lens antioxidant defense mechanism, were also capable to markedly prevent the damaging effects of PON and MGO on lens crystallins, as indicated by gel electrophoresis. The results of this study may highlight the importance of lens antioxidant defense system in protection of crystallins against the structural insults induced by PON and MGO during chronic hyperglycemia in the diabetic patients.

Endothelial dysfunction and vascular disease - a 30th anniversary update

The endothelium can evoke relaxations of the underlying vascular smooth muscle, by releasing vasodilator substances. The best-characterized endothelium-derived relaxing factor (EDRF) is nitric oxide (NO) which activates soluble guanylyl cyclase in the vascular smooth muscle cells, with the production of cyclic guanosine monophosphate (cGMP) initiating relaxation. The endothelial cells also evoke hyperpolarization of the cell membrane of vascular smooth muscle (endothelium-dependent hyperpolarizations, EDH-mediated responses). As regards the latter, hydrogen peroxide (H₂ O₂ ) now appears to play a dominant role. Endothelium-dependent relaxations involve both pertussis toxin-sensitive G_i (e.g. responses to α₂ -adrenergic agonists, serotonin, and thrombin) and pertussis toxin-insensitive G_q (e.g. adenosine diphosphate and bradykinin) coupling proteins. New stimulators (e.g. insulin, adiponectin) of the release of EDRFs have emerged. In recent years, evidence has also accumulated, confirming that the release of NO by the endothelial cell can chronically be upregulated (e.g. by oestrogens, exercise and dietary factors) and downregulated (e.g. oxidative stress, smoking, pollution and oxidized low-density lipoproteins) and that it is reduced with ageing and in the course of vascular disease (e.g. diabetes and hypertension). Arteries covered with regenerated endothelium (e.g. following angioplasty) selectively lose the pertussis toxin-sensitive pathway for NO release which favours vasospasm, thrombosis, penetration of macrophages, cellular growth and the inflammatory reaction leading to atherosclerosis. In addition to the release of NO (and EDH, in particular those due to H₂ O₂ ), endothelial cells also can evoke contraction of the underlying vascular smooth muscle cells by releasing endothelium-derived contracting factors. Recent evidence confirms that most endothelium-dependent acute increases in contractile force are due to the formation of vasoconstrictor prostanoids (endoperoxides and prostacyclin) which activate TP receptors of the vascular smooth muscle cells and that prostacyclin plays a key role in such responses. Endothelium-dependent contractions are exacerbated when the production of nitric oxide is impaired (e.g. by oxidative stress, ageing, spontaneous hypertension and diabetes). They contribute to the blunting of endothelium-dependent vasodilatations in aged subjects and essential hypertensive and diabetic patients. In addition, recent data confirm that the release of endothelin-1 can contribute to endothelial dysfunction and that the peptide appears to be an important contributor to vascular dysfunction. Finally, it has become clear that nitric oxide itself, under certain conditions (e.g. hypoxia), can cause biased activation of soluble guanylyl cyclase leading to the production of cyclic inosine monophosphate (cIMP) rather than cGMP and hence causes contraction rather than relaxation of the underlying vascular smooth muscle.

Oxidative Stress and Salvia miltiorrhiza in Aging-Associated Cardiovascular Diseases

Aging-associated cardiovascular diseases (CVDs) have some risk factors that are closely related to oxidative stress. Salvia miltiorrhiza (SM) has been used commonly to treat CVDs for hundreds of years in the Chinese community. We aimed to explore the effects of SM on oxidative stress in aging-associated CVDs. Through literature searches using Medicine, PubMed, EMBASE, Cochrane library, CINAHL, and Scopus databases, we found that SM not only possesses antioxidant, antiapoptotic, and anti-inflammatory effects but also exerts angiogenic and cardioprotective activities. SM may reduce the production of reactive oxygen species by inhibiting oxidases, reducing the production of superoxide, inhibiting the oxidative modification of low-density lipoproteins, and ameliorating mitochondrial oxidative stress. SM also increases the activities of catalase, manganese superoxide dismutase, glutathione peroxidase, and coupled endothelial nitric oxide synthase. In addition, SM reduces the impact of ischemia/reperfusion injury, prevents cardiac fibrosis after myocardial infarction, preserves cardiac function in coronary disease, maintains the integrity of the blood-brain barrier, and promotes self-renewal and proliferation of neural stem/progenitor cells in stroke. However, future clinical well-designed and randomized control trials will be necessary to confirm the efficacy of SM in aging-associated CVDs.

RhoA/rock signaling mediates peroxynitrite-induced functional impairment of Rat coronary vessels

Background

Diabetes-induced vascular dysfunction may arise from reduced nitric oxide (NO) availability, following interaction with superoxide to form peroxynitrite. Peroxynitrite can induce formation of 3-nitrotyrosine-modified proteins. RhoA/ROCK signaling is also involved in diabetes-induced vascular dysfunction. The study aimed to investigate possible links between Rho/ROCK signaling, hyperglycemia, and peroxynitrite in small coronary arteries.

Methods

Rat small coronary arteries were exposed to normal (NG; 5.5 mM) or high (HG; 23 mM) D-glucose. Vascular ring constriction to 3 mM 4-aminopyridine and dilation to 1 μM forskolin were measured. Protein expression (immunohistochemistry and western blot), mRNA expression (real-time PCR), and protein activity (luminescence-based G-LISA and kinase activity spectroscopy assays) of RhoA, ROCK1, and ROCK2 were determined.

Results

Vascular ring constriction and dilation were smaller in the HG group than in the NG group (P < 0.05); inhibition of RhoA or ROCK partially reversed the effects of HG. Peroxynitrite impaired vascular ring constriction/dilation; this was partially reversed by inhibition of RhoA or ROCK. Protein and mRNA expressions of RhoA, ROCK1, and ROCK2 were higher under HG than NG (P < 0.05). This HG-induced upregulation was attenuated by inhibition of RhoA or ROCK (P < 0.05). HG increased RhoA, ROCK1, and ROCK2 activity (P < 0.05). Peroxynitrite also enhanced RhoA, ROCK1, and ROCK2 activity; these actions were partially inhibited by 100 μM urate (peroxynitrite scavenger). Exogenous peroxynitrite had no effect on the expression of the voltage-dependent K⁺ channels 1.2 and 1.5.

Conclusions

Peroxynitrite-induced coronary vascular dysfunction may be mediated, at least in part, through increased expressions and activities of RhoA, ROCK1, and ROCK2.

The Role of Oxidative Stress in Myocardial Ischemia and Reperfusion Injury and Remodeling: Revisited

Oxidative and reductive stress are dual dynamic phases experienced by the cells undergoing adaptation towards endogenous or exogenous noxious stimulus. The former arises due to the imbalance between the reactive oxygen species production and antioxidant defenses, while the latter is due to the aberrant increase in the reducing equivalents. Mitochondrial malfunction is the common denominator arising from the aberrant functioning of the rheostat that maintains the homeostasis between oxidative and reductive stress. Recent experimental evidences suggest that the maladaptation during oxidative stress could play a pivotal role in the pathophysiology of major cardiovascular diseases such as myocardial infraction, atherosclerosis, and diabetic cardiovascular complications. In this review we have discussed the role of oxidative and reductive stress pathways in the pathogenesis of myocardial ischemia/reperfusion injury and diabetic cardiomyopathy (DCM). Furthermore, we have provided impetus for the development of subcellular organelle targeted antioxidant drug therapy for thwarting the deterioration of the failing myocardium in the aforementioned cardiovascular conditions.

Metabolic memory phenomenon in diabetes mellitus: Achieving and perspectives

Diabetes mellitus (DM) exhibits raised prevalence worldwide. There is a large body of evidence regarding the incidence of DM closely associates with cardiovascular (CV) complications. In this context, hyperglycaemia, oxidant stress, and inflammation are key factors that contribute in CV events and disease in type1 and type 2 DM, even when metabolic control was optimal and/or intensive glycemic control was implemented. It has been suggested that the effect of poor metabolic control or even transient episodes of hyperglycemia in DM associates in particularly with worsening ability of endogenous vasoreparative systems that are mediated epigenetic changes in several cells (progenitor cells, stem cells, mononuclears, immune cells), and thereby lead to so called "vascular glycemic memory" or "metabolic memory". Both terms are emphasized the fact that prior glucose control has sustained effects that persist even after return to more usual glycemic control. The mechanisms underlying the cellular "metabolic memory" induced by high glucose remain unclear. The review is discussed pathophysiology and clinical relevance of "metabolic" memory phenomenon in DM. The role of oxidative stress, inflammation, and epigenetics in DM and its vascular complications are highlighted. The effects of several therapeutic approaches are discussed.

Oral administration of SR-110, a peroxynitrite decomposing catalyst, enhances glucose homeostasis, insulin signaling, and islet architecture in B6D2F1 mice fed a high fat diet

Peroxynitrite has been implicated in type 2 diabetes and diabetic complications. As a follow-up study to our previous work on SR-135 (Arch Biochem Biophys 577-578: 49-59, 2015), we provide evidence that this series of compounds are effective when administered orally, and their mechanisms of actions extend to the peripheral tissues. A more soluble analogue of SR-135, SR-110 (from a new class of Mn(III) bis(hydroxyphenyl)-dipyrromethene complexes) was orally administered for 2 weeks to B6D2F1 mice fed a high fat-diet (HFD). Mice fed a HFD for 4 months gained significantly higher body weights compared to lean diet-fed mice (52 ± 1.5 g vs 34 ± 1.3 g). SR-110 (10 mg/kg daily) treatment significantly reduced fasting blood glucose and insulin levels, and enhanced glucose tolerance as compared to HFD control or vehicle (peanut butter) group. SR-110 treatment enhanced insulin signaling in the peripheral organs, liver, heart, and skeletal muscle, and reduced lipid accumulation in the liver. Furthermore, SR-110 increased insulin content, restored islet architecture, decreased islet size, and reduced tyrosine nitration. These results suggest that a peroxynitrite decomposing catalyst is effective in improving glucose homeostasis and restoring islet morphology and β-cell insulin content under nutrient overload.