Plasma hydrogen peroxide production in human essential hypertension: role of heredity, gender, and ethnicity

Increased TSLP and oxidative stress reflect airway epithelium injury upon cigarette smoke exposure. Is there a role for carbocysteine?

Chronic Obstructive Pulmonary Disease (COPD) is a chronic inflammatory degenerative disease. Disease exacerbations accelerate lung function deterioration. Airway epithelium has a central role in COPD pathophysiology. Airway epithelium releases alarmins including the thymic stromal lymphopoietin (TSLP) in response to exogenous stressors. Notch-1 in the nucleus acts as inhibitor of TSLP gene expression. Here, we investigated, in human bronchial epithelial cells, the effects of cigarette smoke extract (CSE) in TSLP production exploring the relationship with oxidative stress events and with Notch-1 signaling. In CSE exposed 16HBE, the effects of carbocysteine were assessed on: intracellular and extracellular oxidative stress; nuclear Notch-1 expression; TSLP gene expression. The TSLP levels in sera from non-smokers, smokers and exacerbated COPD patients (before and after therapy with carbocysteine) were also explored. CSE induced TSLP gene expression and oxidative stress and reduced nuclear expression of Notch-1 in 16HBE. The use of an electrochemical sensor allowed a reliable tool to assess oxidative stress. TSLP concentrations were higher in sera from smokers and exacerbated COPD than in sera from non-smokers. Carbocysteine was able to counteract the effects of CSE in oxidative stress and in TSLP gene expression in 16HBE and to reduce TSLP in exacerbated COPD. In conclusion, increased oxidative stress induced by smoke exposure in airway epithelium leads to increased TSLP production and carbocysteine in vitro and in vivo mitigates the induced TSLP production. Oxidative stress detection by electrochemical sensors can open new avenues for evaluating epithelial damage and for identifying patients eligible to alarmin targeted biologics.

Thioether Oxidation Chemistry in Reactive Oxygen Species (ROS)-Sensitive Trigger Design: A Kinetic Analysis

Thioether oxidation to sulfoxide by H2O2 has been widely reported as an ROS-sensitive trigger in drug delivery applications. Through a number of straightforward kinetic experiments with a series of aryl thioethers, we show that H2O2 oxidation under near-physiological conditions is expected to have half-lives on the scale of hundreds of hours at pathophysiologically relevant H2O2 concentrations. On the other hand, hypochlorite can oxidize thioethers at much faster rates with half-lives in the range of seconds to sulfoxide and minutes to sulfone under similar conditions. Such information means that hypochlorite likely plays a much more important role than H2O2 in activating thioether-based drug delivery systems.

NPA7: A Dual Receptor Activating Peptide That Inhibits Cardiac Oxidative Stress

BACKGROUND

Cardiomyocyte oxidative stress significantly contributes to the progression of hypertension-induced heart failure, highlighting the need for targeted therapies. We developed a novel peptide, NPA7, that coactivates the GC-A (guanylyl cyclase A)/cGMP and MasR (Mas receptor)/cAMP pathway. This study aimed to test NPA7's ability to inhibit oxidative stress by modulating the p62 (Sequestosome 1)-KEAP1 (Kelch-like ECH-associated protein 1)-NRF2 (nuclear factor erythroid 2-related factor 2) pathway in human cardiomyocytes (HCMs) and a rat model of hypertension.

METHODS

Oxidative stress was induced in HCMs using H2O2 with phosphate-buffered saline or NPA7 treatment. Intracellular reactive oxygen species levels were assessed via dihydroethidium staining. Western blotting analysis measured p62, KEAP1, and NRF2 protein levels, while GSH/GSSG (glutathione/glutathione disulfide) ratios and antioxidant gene expression were analyzed. HCMs were transfected with small interfering RNA targeting GC-A, MasR, or p62 before NPA7 and H2O2 treatment. In vivo, spontaneously hypertensive rats received saline or NPA7, with normotensive Wistar Kyoto rats as control and cardiac oxidative stress, KEAP1 protein levels, NOX2 (NADPH oxidase 2), and p67 (NADPH oxidase subunit p67-phox) mRNA levels were measured.

RESULTS

NPA7 reduced H2O2-induced reactive oxygen species levels and increased GSH/GSSG ratio in HCMs. Silencing GC-A (guanylyl cyclase A receptor) and MasR (Mas receptor) reversed NPA7's effects. NPA7 activated the KEAP1-NRF2 pathway, enhancing NRF2's antioxidant target gene expression. In p62 knockdown HCMs, NPA7-induced KEAP1 degradation and NRF2 activation were diminished. Reactive oxygen species levels were elevated in spontaneously hypertensive rat versusWistar Kyoto rats' hearts, however, NPA7 treatment reduced myocardial reactive oxygen species, suppressed KEAP1 protein, and decreased NOX2 and p67 mRNA levels.

CONCLUSIONS

NPA7 exhibits antioxidant properties in HCMs and spontaneously hypertensive rat hearts by targeting GC-A and MasR through the p62-KEAP1-NRF2 pathway, supporting a novel therapeutic approach against cardiovascular disease-related oxidative stress.

Endogenous/exogenous stimuli‐responsive smart hydrogels for diabetic wound healing

Diabetes significantly impairs the body's wound‐healing capabilities, leading to chronic, infection‐prone wounds. These wounds are characterized by hyperglycemia, inflammation, hypoxia, variable pH levels, increased matrix metalloproteinase activity, oxidative stress, and bacterial colonization. These complex conditions complicate effective wound management, prompting the development of advanced diabetic wound care strategies that exploit specific wound characteristics such as acidic pH, high glucose levels, and oxidative stress to trigger controlled drug release, thereby enhancing the therapeutic effects of the dressings. Among the solutions, hydrogels emerge as promising due to their stimuli‐responsive nature, making them highly effective for managing these wounds. The latest advancements in mono/multi‐stimuli‐responsive smart hydrogels showcase their superiority and potential as healthcare materials, as highlighted by relevant case studies. However, traditional wound dressings fall short of meeting the nuanced needs of these wounds, such as adjustable adhesion, easy removal, real‐time wound status monitoring, and dynamic drug release adjustment according to the wound's specific conditions. Responsive hydrogels represent a significant leap forward as advanced dressings proficient in sensing and responding to the wound environment, offering a more targeted approach to diabetic wound treatment. This review highlights recent advancements in smart hydrogels for wound dressing, monitoring, and drug delivery, emphasizing their role in improving diabetic wound healing. It addresses ongoing challenges and future directions, aiming to guide their clinical adoption.

The association between dietary selenium intake and telomere length in hypertension

Telomere length is closely linked to biological aging, oxidative stress, and the development of cardiovascular diseases. This study aimed to assess the association between dietary selenium intake and telomere length in individuals with hypertension. Data on dietary selenium intake were captured through the National Health and Nutrition Examination Survey (NHANES) computer-assisted dietary interview system (CADI). Telomere length determination entailed selecting blood samples from all participants in the NHANES database. The analysis was performed using Analysis System software, with Empower stats utilized for data analysis. Results showed that there was a significant association between dietary selenium intake and telomere length in hypertension, particularly within the female group. In female hypertension cases, a 1 mcg increase in dietary selenium intake corresponded to a telomere length increase of 1.19 bp, even after adjusting for age, race, BMI, marital status, physical activity, energy intake, and stroke history. The relationship between dietary selenium intake and telomere length exhibited a linear pattern in female hypertension patients. This study identified a positive association between dietary selenium intake and telomere length in hypertension, particularly within the female group.

Quantitative Factors Introduced in the Feasibility Analysis of Reactive Oxygen Species (ROS)-Sensitive Triggers

Reactive oxygen species (ROS) are critical for cellular signaling. Various pathophysiological conditions are also associated with elevated levels of ROS. Hence, ROS-sensitive triggers have been extensively used for selective payload delivery. Such applications are predicated on two key functions: (1) a sufficient magnitude of concentration difference for the interested ROS between normal tissue/cells and intended sites and (2) appropriate reaction kinetics to ensure a sufficient level of selectivity for payload release. Further, ROS refers to a group of species with varying reactivity, which should not be viewed as a uniform group. In this review, we critically analyze data on the concentrations of different ROS species under various pathophysiological conditions and examine how reaction kinetics affect the success of ROS-sensitive linker chemistry. Further, we discuss different ROS linker chemistry in the context of their applications in drug delivery and imaging. This review brings new insights into research in ROS-triggered delivery, highlights factors to consider in maximizing the chance for success and discusses pitfalls to avoid.

Recent advances of hydrogels as smart dressings for diabetic wounds

Chronic diabetic wounds have been an urgent clinical problem, and wound dressings play an important role in their management. Due to the design of traditional dressings, it is difficult to achieve adaptive adhesion and on-demand removal of complex diabetic wounds, real-time monitoring of wound status, and dynamic adjustment of drug release behavior according to the wound microenvironment. Smart hydrogels, as smart dressings, can respond to environmental stimuli and achieve more precise local treatment. Here, we review the latest progress of smart hydrogels in wound bandaging, dynamic monitoring, and drug delivery for treatment of diabetic wounds. It is worth noting that we have summarized the most important properties of smart hydrogels for diabetic wound healing. In addition, we discuss the unresolved challenges and future prospects in this field. We hope that this review will contribute to furthering progress on smart hydrogels as improved dressing for diabetic wound healing and practical clinical application.

Potential Benefits of Antioxidant Phytochemicals in Type 2 Diabetes

The clinical relationship between diabetes and inflammation is well established. Evidence clearly indicates that disrupting oxidant-antioxidant equilibrium and elevated lipid peroxidation could be a potential mechanism for chronic kidney disease associated with type 2 diabetes mellitus (T2DM). Under diabetic conditions, hyperglycemia, especially inflammation, and increased reactive oxygen species generation are bidirectionally associated. Inflammation, oxidative stress, and tissue damage are believed to play a role in the development of diabetes. Although the exact mechanism underlying oxidative stress and its impact on diabetes progression remains uncertain, the hyperglycemia-inflammation-oxidative stress interaction clearly plays a significant role in the onset and progression of vascular disease, kidney disease, hepatic injury, and pancreas damage and, therefore, holds promise as a therapeutic target. Evidence strongly indicates that the use of multiple antidiabetic medications fails to achieve the normal range for glycated hemoglobin targets, signifying treatment-resistant diabetes. Antioxidants with polyphenols are considered useful as adjuvant therapy for their potential anti-inflammatory effect and antioxidant activity. We aimed to analyze the current major points reported in preclinical, in vivo, and clinical studies of antioxidants in the prevention or treatment of inflammation in T2DM. Then, we will share our speculative vision for future diabetes clinical trials.

Recent Advancement of Functional Hydrogels toward Diabetic Wound Management

Wound healing is a dynamic, orchestrated process comprising partially overlapping phases of hemostasis, inflammation, proliferation, and remodeling. This programmed process, dysregulated in diabetic individuals, results in chronic diabetic wounds. The normal process of healing halts at the inflammatory stage, and this prolonged inflammatory phase is characteristic of diabetic wounds. There are a few U.S. Food & Drug Administration approved skin substitutes; dermal matrixes are commercially available to manage diabetic wounds. However, expensiveness and nonresponsiveness in a few instances are the major limitations of such modalities. To address the issues, several treatment strategies have been exploited to treat chronic wounds; among them hydrogel-based systems showed promise due to favorable properties such as excellent absorption capabilities, porous structure, tunable mechanical strength, and biocompatibility. In the past two decades, hydrogels have become one of the most acceptable systems in the field of wound dressing material, offering single functionality to multifunctionality. This review focuses on the advancement of functional hydrogels explored for diabetic wound management. The process of diabetic wound healing is discussed in the light of the normal healing process, and the role of macrophages in the process is explained. This review also discusses the different approaches to treat diabetic wounds using functional hydrogels, along with their future opportunities.

Involvement of AGE and Its Receptors in the Pathogenesis of Hypertension in Elderly People and Its Treatment

Both systolic and diastolic blood pressures increase with age up to 50 to 60 years of age. After 60 years of age systolic pressure rises to 84 years of age but diastolic pressure remains stable or even decreases. In the oldest age group (85-99 years), the systolic blood pressure (SBP) is high and diastolic pressure (DBP) is the lowest. Seventy percent of people older than 65 years are hypertensive. This paper deals with the role of advanced glycation end products (AGE) and its cell receptor (RAGE) and soluble receptor (sRAGE) in the development of hypertension in the elderly population. Plasma/serum levels of AGE are higher in older people as compared with younger people. Serum levels of AGE are positively correlated with age, arterial stiffness, and hypertension. Low serum levels of sRAGE are associated with arterial stiffness and hypertension. Levels of sRAGE are negatively correlated with age and blood pressure. Levels of sRAGE are lower in patients with arterial stiffness and hypertension than patients with high levels of sRAGE. AGE could induce hypertension through numerous mechanisms including, cross-linking with collagen, reduction of nitric oxide, increased expression of endothelin-1, and transforming growth factor-β (TGF-β). Interaction of AGE with RAGE could produce hypertension through the generation of reactive oxygen species, increased sympathetic activity, activation of nuclear factor-kB, and increased expression of cytokines, cell adhesion molecules, and TGF- β. In conclusion, the AGE-RAGE axis could be involved in hypertension in elderly people. Treatment for hypertension in elderly people should be targeted at reduction of AGE levels in the body, prevention of AGE formation, degradation of AGE in vivo, downregulation of RAGE expression, blockade of AGE-RAGE interaction, upregulation of sRAGE expression, and use of antioxidants.

A Combination Therapy Using Electrical Stimulation and Adaptive, Conductive Hydrogels Loaded with Self-Assembled Nanogels Incorporating Short Interfering RNA Promotes the Repair of Diabetic Chronic Wounds

In addition to oxidative stress and impaired angiogenesis, the overexpression of metalloproteinases (MMPs) and proinflammatory cytokines, which are promoted by hyperglycemia, causes chronic inflammation in diabetic wounds. Herein, TA-siRNA nanogels are prepared for the first time on the basis of the self-assembling interaction between tannic acid (TA) and short interfering RNA (siRNA). The efficient, biodegradable nanogels are cross-linked with poly(vinyl alcohol) (PVA), human-like collagen (HLC), TA, and borax to prepare adaptive, conductive PHTB (TA-siRNA) hydrogels. In response to high levels of reactive oxygen species (ROS), the ROS-responsive borate ester bonds in the hydrogels are oxidized and broken, and TA-siRNA nanogels are released into cells to reduce the expression of the MMP-9. Moreover, the TA and HLC promote collagen expression, reduce inflammation, and ROS level. It is found that electrical stimulation (ES) promotes the in vivo release of TA-siRNA nanogels from PHTB (TA-siRNA) hydrogels and endocytosis of the nanogels. The combination therapy using ES and PHTB (TA-siRNA) hydrogels accelerates the healing of diabetic wounds by reducing the levels of ROS and MMP-9 and promoting the polarization of macrophages, production of collagen, and angiogenesis. This study provides insights on the design of functional gene-delivery and efficient therapeutic strategies to promote the repair of diabetic chronic wounds.

Endothelial Cells and the Cerebral Circulation

Endothelial cells form the innermost layer of all blood vessels and are the only vascular component that remains throughout all vascular segments. The cerebral vasculature has several unique properties not found in the peripheral circulation; this requires that the cerebral endothelium be considered as a unique entity. Cerebral endothelial cells perform several functions vital for brain health. The cerebral vasculature is responsible for protecting the brain from external threats carried in the blood. The endothelial cells are central to this requirement as they form the basis of the blood-brain barrier. The endothelium also regulates fibrinolysis, thrombosis, platelet activation, vascular permeability, metabolism, catabolism, inflammation, and white cell trafficking. Endothelial cells regulate the changes in vascular structure caused by angiogenesis and artery remodeling. Further, the endothelium contributes to vascular tone, allowing proper perfusion of the brain which has high energy demands and no energy stores. In this article, we discuss the basic anatomy and physiology of the cerebral endothelium. Where appropriate, we discuss the detrimental effects of high blood pressure on the cerebral endothelium and the contribution of cerebrovascular disease endothelial dysfunction and dementia. © 2022 American Physiological Society. Compr Physiol 12:3449-3508, 2022.

Positive Aspects of Oxidative Stress at Different Levels of the Human Body: A Review

Oxidative stress is the subject of numerous studies, most of them focusing on the negative effects exerted at both molecular and cellular levels, ignoring the possible benefits of free radicals. More and more people admit to having heard of the term "oxidative stress", but few of them understand the meaning of it. We summarized and analyzed the published literature data in order to emphasize the importance and adaptation mechanisms of basal oxidative stress. This review aims to provide an overview of the mechanisms underlying the positive effects of oxidative stress, highlighting these effects, as well as the risks for the population consuming higher doses than the recommended daily intake of antioxidants. The biological dose-response curve in oxidative stress is unpredictable as reactive species are clearly responsible for cellular degradation, whereas antioxidant therapies can alleviate senescence by maintaining redox balance; nevertheless, excessive doses of the latter can modify the redox balance of the cell, leading to a negative outcome. It can be stated that the presence of oxidative status or oxidative stress is a physiological condition with well-defined roles, yet these have been insufficiently researched and explored. The involvement of reactive oxygen species in the pathophysiology of some associated diseases is well-known and the involvement of antioxidant therapies in the processes of senescence, apoptosis, autophagy, and the maintenance of cellular homeostasis cannot be denied. All data in this review support the idea that oxidative stress is an undesirable phenomenon in high and long-term concentrations, but regular exposure is consistent with the hormetic theory.

Leveraging avidin-biotin interaction to quantify permeability property of microvessels-on-a-chip networks

Microvessels-on-a-chip have enabled in vitro studies to closely simulate in vivo microvessel environment. However, assessing microvessel permeability, a functional measure of microvascular exchange, has not been attainable in nonpermeable microfluidic platforms. This study developed a new approach that enables permeability coefficients (P_s) to be quantified in microvessels developed in nonpermeable chip platforms by integrating avidin-biotin technology. Microvessels were developed on biotinylated fibronectin-coated microfluidic channels. Solute transport was assessed by perfusing microvessels with fluorescence-labeled avidin. Avidin molecules that crossed endothelium were captured by substrate biotin and recorded with real-time confocal images. The P_s was derived from the rate of avidin-biotin accumulation at the substrate relative to solute concentration difference across microvessel wall. Avidin tracers with different physiochemical properties were used to characterize the barrier properties of the microvessel wall. The measured baseline P_s and inflammatory mediator-induced increases in P_s and endothelial cell (EC) [Ca²⁺]_i resembled those observed in intact microvessels. Importantly, the spatial accumulation of avidin-biotin at substrate defines the transport pathways. Glycocalyx layer is well formed on endothelium and its degradation increased transcellular transport without affecting EC junctions. This study demonstrated that in vitro microvessels developed in this simply designed microfluidics structurally possess in vivo-like glycocalyx layer and EC junctions and functionally recapitulate basal barrier properties and stimuli-induced responses observed in intact microvessels. This new approach overcomes the limitations of nonpermeable microfluidics and provides an easily executed highly reproducible in vitro microvessel model with in vivo microvessel functionality, suitable for a wide range of applications in blood and vascular research and drug development.NEW & NOTEWORTHY Our study developed a novel method that allows permeability coefficient to be measured in microvessels developed in nonpermeable microfluidic platforms using avidin-biotin technology. It overcomes the major limitation of nonpermeable microfluidic system and provides a simply designed easily executed and highly reproducible in vitro microvessel model with permeability accessibility. This model with in vivo-like endothelial junctions, glycocalyx, and permeability properties advances microfluidics in microvascular research, suitable for a wide range of biomedical and clinical applications.

Heme-oxygenase and lipid mediators in obesity and associated cardiometabolic diseases: Therapeutic implications

Obesity-mediated metabolic syndrome remains the leading cause of death worldwide. Among many potential targets for pharmacological intervention, a promising strategy involves the heme oxygenase (HO) system, specifically its inducible form, HO-1. This review collects and updates much of the current knowledge relevant to pharmacology and clinical medicine concerning HO-1 in metabolic diseases and its effect on lipid metabolism. HO-1 has pleotropic effects that collectively reduce inflammation, while increasing vasodilation and insulin and leptin sensitivity. Recent reports indicate that HO-1 with its antioxidants via the effect of bilirubin increases formation of biologically active lipid metabolites such as epoxyeicosatrienoic acid (EET), omega-3 and other polyunsaturated fatty acids (PUFAs). Similarly, HO-1and bilirubin are potential therapeutic targets in the treatment of fat-induced liver diseases. HO-1-mediated upregulation of EET is capable not only of reversing endothelial dysfunction and hypertension, but also of reversing cardiac remodeling, a hallmark of the metabolic syndrome. This process involves browning of white fat tissue (i.e. formation of healthy adipocytes) and reduced lipotoxicity, which otherwise will be toxic to the heart. More importantly, this review examines the activity of EET in biological systems and a series of pathways that explain its mechanism of action and discusses how these might be exploited for potential therapeutic use. We also discuss the link between cardiac ectopic fat deposition and cardiac function in humans, which is similar to that described in obese mice and is regulated by HO-1-EET-PGC1α signaling, a potent negative regulator of the inflammatory adipokine NOV.

Targeting oxidative stress in disease: promise and limitations of antioxidant therapy

Oxidative stress is a component of many diseases, including atherosclerosis, chronic obstructive pulmonary disease, Alzheimer disease and cancer. Although numerous small molecules evaluated as antioxidants have exhibited therapeutic potential in preclinical studies, clinical trial results have been disappointing. A greater understanding of the mechanisms through which antioxidants act and where and when they are effective may provide a rational approach that leads to greater pharmacological success. Here, we review the relationships between oxidative stress, redox signalling and disease, the mechanisms through which oxidative stress can contribute to pathology, how antioxidant defences work, what limits their effectiveness and how antioxidant defences can be increased through physiological signalling, dietary components and potential pharmaceutical intervention.

Functional hydrogels for diabetic wound management

Diabetic wounds often have a slow healing process and become easily infected owing to hyperglycemia in wound beds. Once planktonic bacterial cells develop into biofilms, the diabetic wound becomes more resistant to treatment. Although it remains challenging to accelerate healing in a diabetic wound due to complex pathology, including bacterial infection, high reactive oxygen species, chronic inflammation, and impaired angiogenesis, the development of multifunctional hydrogels is a promising strategy. Multiple functions, including antibacterial, pro-angiogenesis, and overall pro-healing, are high priorities. Here, design strategies, mechanisms of action, performance, and application of functional hydrogels are systematically discussed. The unique properties of hydrogels, including bactericidal and wound healing promotive effects, are reviewed. Considering the clinical need, stimuli-responsive and multifunctional hydrogels that can accelerate diabetic wound healing are likely to form an important part of future diabetic wound management.

Inhibition Properties of Arylsulfatase and β-Glucuronidase by Hydrogen Peroxide, Hypochlorite, and Peracetic Acid

Arylsulfatase and β-glucuronidase are two important enzymes in humans, which play an important role in the dynamic equilibrium of steroidal estrogens. This work probably for the first time reported that hydrogen peroxide (H₂O₂), hypochlorite, and peracetic acid (PAA) could effectively inhibit the activities of arylsulfatase and/or β-glucuronidase. The 50% of inhibitions (IC₅₀) of H₂O₂, hypochlorite, and PAA on arylsulfatase were found to be 142.90 ± 9.00, 91.83 ± 10.01, and 43.46 ± 2.92 μM, respectively. The corresponding IC₅₀ values of hypochlorite and PAA on β-glucuronidase were 704.90 ± 41.40 and 23.26 ± 0.82 μM, whereas H₂O₂ showed no inhibition on β-glucuronidase. The inhibitions of arylsulfatase and/or β-glucuronidase by these three chemicals were pH-dependent. It was further revealed that the inhibitions of hypochlorite on both arylsulfatase and β-glucuronidase were irreversible. On the contrary, the inhibitions by H₂O₂ and PAA were reversible. In addition, the inhibition by H₂O₂ was competitive and that by PAA was noncompetitive. In general, H₂O₂ and hypochlorite can be endogenously produced in humans, which suggested that the two compounds are potential endocrine disruption compounds (EDCs) as they can cause endocrine disruption via the inhibition of arylsulfatase and β-glucuronidase. This work further indicated that any agent that can induce the production of H₂O₂ or hypochlorite in humans is a potential EDC, which explains why some EDCs with very weak or no estrogenic potency can cause endocrine disruption, which is confirmed in epidemiological studies.

Association between genetic polymorphisms of telomere pathway genes and hydrogen peroxide level in omethoate exposure workers

OBJECTIVE

The aim of this study was to explore the association between genetic variations in telomere pathway genes and the level of hydrogen peroxide (H₂O₂) in omethoate exposure workers.

METHODS

A total of 180 omethoate exposure workers and 115 healthy controls were recruited. The level of H₂O₂ in plasma was determined with molybdenic acid colorimetry. Polymerase chain reaction and restriction fragment length was used to detect polymorphisms in POT1 rs1034794, POT1 rs10250202, TERF1 rs3863242, and TERT rs2736098.

RESULTS

The level of H₂O₂ in exposure group (4.26 ± 0.71) was significantly higher than that in control group (3.29 ± 0.46). Generalized linear models indicated that risk factors for the increase H₂O₂ level were exposure [β(95 % CI) = 0.951 (0.806, 1.096), P < 0.001] and AA + AT genotype in POT1 rs034794 [β(95 % CI) = 0.397 (0.049, 0.745), P = 0.025].

CONCLUSION

The increase H₂O₂ level was associated with omethoate exposure and AA + AT genotypes in POT1 gene rs1034794. It provided a new idea that polymorphisms in telomere pathway genes may indirectly regulate telomere length by influencing oxidative stress.

Assessment of Plasma Sodium to Potassium Ratio, Renal Function, Markers of Oxidative Stress, Inflammation, and Endothelial Dysfunction in Nigerian Hypertensive Patients

Background

This study investigated plasma sodium/potassium ratio, markers of oxidative stress, renal function, and endothelial dysfunction in hypertensive Nigerians.

Materials and Methods

Five hundred forty-nine volunteers consisting of three hundred and twenty-four hypertensive and two hundred twenty-five controls participated in this study. Blood samples were collected from the participants and were analyzed for electrolytes, markers of oxidative stress, endothelial dysfunction, renal function, and inflammation, using ion-selective electrodes, spectrophotometric, and enzyme-linked immunosorbent assay methods, respectively.

Results

The mean systolic blood pressure, mean diastolic blood pressure, mean arterial blood pressure, and body mass index (BMI) were significantly elevated among the hypertensive group when compared with control (p < 0.001). The mean sodium increased, while potassium and bicarbonate (HCO₃⁻) decreased (p < 0.001) in hypertensive volunteers. The sodium-potassium ratio (Na⁺/K⁺) and urea were raised (p < 0.001) in the hypertensive group when compared with the control. Glutathione, superoxide dismutase, nitric oxide (NO), and catalase were significantly reduced (p < 0.001) while malondialdehyde (MDA), high-sensitivity C-reactive protein (hs-CRP), and ferritin were raised significantly (p < 0.001) in hypertensive participants. The odds of hypertension and its complications increased (p < 0.001) with an increase in BMI, Na⁺/K⁺, hs-CRP, MDA, and ferritin and a decrease in estimated glomerular filtration rate (eGFR), glutathione, superoxide dismutase, and catalase.

Conclusion

An increase in Na⁺/K⁺, urea, hs-CRP, ferritin, MDA, and BMI and a decrease in eGFR, glutathione, and superoxide dismutase were associated with an increased risk of hypertension complication. Abnormal values of markers of oxidative stress, inflammation, and endothelial function could impact deleterious effects on the cardiovascular system among hypertensive Nigerians. A decreased bicarbonate possibly suggests an occult acid-base imbalance among hypertensive volunteers.

Cellular and Molecular Processes in Pulmonary Hypertension

Pulmonary hypertension (PH) is a progressive lung disease characterized by persistent pulmonary vasoconstriction. Another well-recognized characteristic of PH is the muscularization of peripheral pulmonary arteries. This pulmonary vasoremodeling manifests in medial hypertrophy/hyperplasia of smooth muscle cells (SMCs) with possible neointimal formation. The underlying molecular processes for these two major vascular responses remain not fully understood. On the other hand, a series of very recent studies have shown that the increased reactive oxygen species (ROS) seems to be an important player in mediating pulmonary vasoconstriction and vasoremodeling, thereby leading to PH. Mitochondria are a primary site for ROS production in pulmonary artery (PA) SMCs, which subsequently activate NADPH oxidase to induce further ROS generation, i.e., ROS-induced ROS generation. ROS control the activity of multiple ion channels to induce intracellular Ca²⁺ release and extracellular Ca²⁺ influx (ROS-induced Ca²⁺ release and influx) to cause PH. ROS and Ca²⁺ signaling may synergistically trigger an inflammatory cascade to implicate in PH. Accordingly, this paper explores the important roles of ROS, Ca²⁺, and inflammatory signaling in the development of PH, including their reciprocal interactions, key molecules, and possible therapeutic targets.

Biomedical Application of Reactive Oxygen Species-Responsive Nanocarriers in Cancer, Inflammation, and Neurodegenerative Diseases

Numerous pathological conditions, including cancer, inflammatory diseases, and neurodegenerative diseases, are accompanied by overproduction of reactive oxygen species (ROS). This makes ROS vital flagging molecules in disease pathology. ROS-responsive drug delivery platforms have been developed. Nanotechnology has been broadly applied in the field of biomedicine leading to the progress of ROS-responsive nanoparticles. In this review, we focused on the production and physiological/pathophysiological impact of ROS. Particular emphasis is put on the mechanisms and effects of abnormal ROS levels on oxidative stress diseases, including cancer, inflammatory disease, and neurodegenerative diseases. Finally, we summarized the potential biomedical applications of ROS-responsive nanocarriers in these oxidative stress diseases. We provide insights that will help in the designing of new ROS-responsive nanocarriers for various applications.

Synthesis and characterization of a hyaluronic acid-based hydrogel with antioxidative and thermosensitive properties

Peripheral arterial disease (PAD) is initiated by progressive atherosclerotic blockages of the arteries supplying the lower extremities. The most common presentation of PAD is claudication (leg pain and severe walking limitation), with many patients progressing to limb threatening ischemia and amputation. Biomaterial approaches are just beginning to be explored in the therapy of PAD with different materials now being evaluated for the delivery of cells or growth factors in animal models of PAD. A biomaterial matrix optimized for minimally invasive injection in the ischemic leg muscles of patients with PAD is urgently needed. There are several important requirements for optimal delivery, retention, and performance of a biomaterial matrix in the mechanically, histologically, and biochemically dynamic intramuscular environment of the PAD leg. Ideally, the material should have mechanical properties matching those of the recipient muscle, undergo minimal swelling, and should introduce properties that can ameliorate the mechanisms operating in PAD like oxidative stress and damage. Here we have developed an injectable, antioxidative, and thermosensitive hydrogel system based on hyaluronic acid (HA). We first synthesized a unique crosslinker of disulfide-modified poloxamer F127 diacrylate. This crosslinker led to the creation of a thermosensitive HA hydrogel with minimal swelling and muscle-matching mechanical properties. We introduced unique disulfide groups into hydrogels which functioned as an effective reactive oxygen species scavenger, exhibited hydrogen peroxide (H2O2)-responsive degradation, and protected cells against H2O2-induced damage. Our antioxidative thermosensitive HA hydrogel system holds great potential for the treatment of the ischemic legs of patients with PAD.

Sex differences and Tat expression affect dopaminergic receptor expression and response to antioxidant treatment in methamphetamine-sensitized HIV Tat transgenic mice

Methamphetamine (Meth) abuse is a common HIV comorbidity. Males and females differ in their patterns of Meth use, associated behaviors, and responses, but the underlying mechanisms and impact of HIV infection are unclear. Transgenic mice with inducible HIV-1 Tat protein in the brain (iTat) replicate many neurological aspects of HIV infection in humans. We previously showed that Tat induction enhances the Meth sensitization response associated with perturbation of the dopaminergic system, in male iTat mice. Here, we used the iTat mouse model to investigate sex differences in individual and interactive effects of Tat and Meth challenge on locomotor sensitization, brain expression of dopamine receptors (DRDs) and regulatory adenosine receptors (ADORAs). Because Meth administration increases the production of reactive oxygen species (ROS), we also determined whether the effects of Meth could be rescued by concomitant treatment with the ROS scavenger N-acetyl cysteine (NAC). After Meth sensitization and a 7-day abstinence period, groups of Tat+ and Tat-male and female mice were challenged with Meth in combination with NAC. We confirmed that Tat expression and Meth challenge suppressed DRD mRNA and protein in males and females' brains, and showed that females were particularly susceptible to the effects of Meth on D1-like and D2-like DRD subtypes and ADORAs. The expression of these markers differed strikingly between males and females, and between females in different phases of the estrous cycle, in a Tat -dependent manner. NAC attenuated Meth-induced locomotor sensitization and preserved DRD expression in all groups except for Tat + females. These data identify complex interactions between sex, Meth use, and HIV infection on addiction responses, with potential implications for the treatment of male and female Meth users in the context of HIV, especially those with cognitive disorders.

Oxidative Stress and Microvessel Barrier Dysfunction

Clinical and experimental evidence indicate that increased vascular permeability contributes to many disease-associated vascular complications. Oxidative stress with increased production of reactive oxygen species (ROS) has been implicated in a wide variety of pathological conditions, including inflammation and many cardiovascular diseases. It is thus important to identify the role of ROS and their mechanistic significance in microvessel barrier dysfunction under pathological conditions. The role of specific ROS and their cross talk in pathological processes is complex. The mechanisms of ROS-induced increases in vascular permeability remain poorly understood. The sources of ROS in diseases have been extensively reviewed at enzyme levels. This review will instead focus on the underlying mechanisms of ROS release by leukocytes, the differentiate effects and signaling mechanisms of individual ROS on endothelial cells, pericytes and microvessel barrier function, as well as the interplay of reactive oxygen species, nitric oxide, and nitrogen species in ROS-mediated vascular barrier dysfunction. As a counter balance of excessive ROS, nuclear factor erythroid 2 related factor 2 (Nrf2), a redox-sensitive cell-protective transcription factor, will be highlighted as a potential therapeutic target for antioxidant defenses. The advantages and limitations of different experimental approaches used for the study of ROS-induced endothelial barrier function are also discussed. This article will outline the advances emerged mainly from in vivo and ex vivo studies and attempt to consolidate some of the opposing views in the field, and hence provide a better understanding of ROS-mediated microvessel barrier dysfunction and benefit the development of therapeutic strategies.

Enzyme catalysis powered micro/nanomotors for biomedical applications

This review provides insights on enzyme powered motors using fuels present in biological environments for biomedical applications.

Co-exposure to polycyclic aromatic hydrocarbons and metals, four common polymorphisms in microRNA genes, and their gene-environment interactions: Influences on oxidative damage levels in Chinese coke oven workers

BACKGROUND

Human are often simultaneously exposed to polycyclic aromatic hydrocarbons (PAHs) and metals, yet relatively little is known regarding their co-exposure effects on oxidative damage. Genetic factors and the gene-environment interactions can also determine the severity of oxidative damage. Four polymorphisms in microRNA (miRNA) genes (rs11614913, rs2292832, rs2910164, and rs3746444) have been well-studied to be associated with oxidative damage-related diseases.

OBJECTIVE

To investigate the influences of PAH-metal co-exposure, four polymorphisms, and their interactions on oxidative damage levels.

METHODS

We conducted a cross-sectional study in 1385 coke oven workers. We quantified exposure levels of PAHs and metals by urinary monohydroxy-PAHs, plasma benzo[a]pyrene-7,8-diol-9,10-epoxide-albumin adducts, and urinary metals, respectively, and measured oxidative damage levels by 8-iso-prostaglandin-F2α and 8-hydroxydeoxyguanosine. We also genotyped four polymorphisms.

RESULTS

In multiple-pollutant models, 8-iso-prostaglandin-F2α and 8-hydroxydeoxyguanosine were associated with multiple PAH exposure biomarkers, as well as with multiple metals (p_trend < 0.05). Metabolites of phenanthrene and pyrene interacted synergistically with lead and zinc to influence 8-iso-prostaglandin-F2α (β_interaction > 7.75%, false discovery rate-adjusted p_interaction ≤ 2.25 × 10^-5). Significantly higher 8-hydroxydeoxyguanosine was observed in carriers of rs11614913 CC variant homozygote than TC carriers (p = 0.037). Associations of the number of rs11614913 C allele with increased 8-iso-prostaglandin-F2α and 8-hydroxydeoxyguanosine were significant (β_std > 0, p_trend < 0.05) and more pronounced in workers with lower metals [p for modifying effect (p_ME) < 0.040]. Positive associations of some PAHs and metals with 8-iso-prostaglandin-F2α and 8-hydroxydeoxyguanosine were weaker in carriers of rs11614913 CC genotype or C allele (p_ME < 0.05).

CONCLUSION

PAH-metal co-exposure, rs11614913, and their interactions may affect oxidative damage levels in Chinese population in a complex manner that are worthy of further investigation.

Epithelial sodium channels in endothelial cells mediate diet-induced endothelium stiffness and impaired vascular relaxation in obese female mice

OBJECTIVE

Mineralocorticoid receptor activation of the epithelial sodium channel in endothelial cells (ECs) (EnNaC) is accompanied by aldosterone induced endothelial stiffening and impaired nitric oxide (NO)-mediated arterial relaxation. Recent data support enhanced activity of the alpha subunit of EnNaC (αEnNaC) mediates this aldosterone induced endothelial stiffening and associated endothelial NO synthase (eNOS) activation. There is mounting evidence that diet induced obesity diminishes expression and activation of AMP-activated protein kinase α (AMPKα), sirtuin 1 (Sirt1), which would be expected to lead to impaired downstream eNOS activation. Thereby, we posited that enhanced EnNaC activation contributes to diet induced obesity related increases in stiffness of the endothelium and diminished NO mediated vascular relaxation by increasing oxidative stress and related inhibition of AMPKα, Sirt1, and associated eNOS inactivation.

MATERIALS/METHODS

Sixteen to twenty week-old αEnNaC knockout (αEnNaC^-/-) and wild type littermate (EnNaC^+/+) female mice were fed a mouse chow or an obesogenic western diet (WD) containing excess fat (46%) and fructose (17.5%) for 16 weeks. Sodium currents of ECs, endothelial stiffness and NO mediated aortic relaxation were examined along with indices of aortic oxidative stress, vascular remodeling and fibrosis.

RESULTS

Enhanced EnNaC activation-mediated WD-induced increases in sodium currents in isolated lung ECs, increased endothelial stiffness and impaired aortic endothelium-dependent relaxation to acetylcholine (10^-9-10^-4 mol/L). These abnormalities occurred in conjunction with WD-mediated aortic tissue oxidative stress, inflammation, and decreased activation of AMPKα, Sirt1, and downstream eNOS were substantially mitigated in αEnNaC^-/- mice. Importantly, αEnNaC^-/- prevented WD induced increases in endothelial stiffness and related impairment of endothelium-dependent relaxation as well as aortic fibrosis and remodeling. However, EnNaC signaling was not involved in diet-induced abnormal expression of adipokines and CYP11b2 in abdominal aortic perivascular adipose tissue.

CONCLUSION

These data suggest that endothelial specific EnNaC activation mediates WD-induced endothelial stiffness, impaired eNOS activation, aortic fibrosis and remodeling through increased aortic oxidative stress and increased inflammation related to a reduction of AMPKα and Sirt 1 mediated eNOS phosphorylation/activation and NO production.

Genetic polymorphisms associated with reactive oxygen species and blood pressure regulation

Hypertension is the most prevalent cause of cardiovascular disease and kidney failure, but only about 50% of patients achieve adequate blood pressure control, in part, due to inter-individual genetic variations in the response to antihypertensive medication. Significant strides have been made toward the understanding of the role of reactive oxygen species (ROS) in the regulation of the cardiovascular system. However, the role of ROS in human hypertension is still unclear. Polymorphisms of some genes involved in the regulation of ROS production are associated with hypertension, suggesting their potential influence on blood pressure control and response to antihypertensive medication. This review provides an update on the genes associated with the regulation of ROS production in hypertension and discusses the controversies on the use of antioxidants in the treatment of hypertension, including the antioxidant effects of antihypertensive drugs.

H2 O2 -induced microvessel barrier dysfunction: the interplay between reactive oxygen species, nitric oxide, and peroxynitrite

Elevated H2 O2 is implicated in many cardiovascular diseases. We previously demonstrated that H2 O2 -induced endothelial nitric oxide synthase (eNOS) activation and excessive NO production contribute to vascular cell injury and increases in microvessel permeability. However, the mechanisms of excessive NO-mediated vascular injury and hyperpermeability remain unknown. This study aims to examine the functional role of NO-derived peroxynitrite (ONOO- ) in H2 O2 -induced vascular barrier dysfunction by elucidating the interrelationships between H2 O2 -induced NO, superoxide, ONOO- , and changes in endothelial [Ca2+ ]i and microvessel permeability. Experiments were conducted on intact rat mesenteric venules. Microvessel permeability was determined by measuring hydraulic conductivity (Lp). Endothelial [Ca2+ ]i , NO, and O2- were assessed with fluorescence imaging. Perfusion of vessels with H2 O2 (10 µmol/L) induced marked productions of NO and O2- , resulting in extensive protein tyrosine nitration, a biomarker of ONOO- . The formation of ONOO- was abolished by inhibition of NOS with NG -Methyl-L-arginine. Blocking NO production or scavenging ONOO- by uric acid prevented H2 O2 -induced increases in endothelial [Ca2+ ]i and Lp. Additionally, the application of exogenous ONOO- to microvessels induced delayed and progressive increases in endothelial [Ca2+ ]i and microvessel Lp, a pattern similar to that observed in H2 O2 -perfused vessels. Importantly, ONOO- caused further activation of eNOS with amplified NO production. We conclude that the augmentation of NO-derived ONOO- is essential for H2 O2 -induced endothelial Ca2+ overload and progressively increased microvessel permeability, which is achieved by self-promoted amplifications of NO-dependent signaling cascades. This novel mechanism provides new insight into the reactive oxygen and/or reactive nitrogen species-mediated vascular dysfunction in cardiovascular diseases.

Spectrophotometric determination of trace hydrogen peroxide via the oxidative coloration of DPD using a Fenton system

A low-cost and environmentally-friendly spectrophotometric method for hydrogen peroxide (H₂O₂) determination based on the oxidative coloration reaction of N,N'-diethyl-p-phenylenediamine (DPD) via the Fenton reactions in aqueous water was established. The generated pink radical cation (DPD⁺) showed maximum absorption at 551 nm. Importantly, under the optimal conditions (pH 3.0, 20 mM DPD, 1.5 mM Fe(II) and reaction time of 45 s), the increase in absorbance at 551 nm for DPD⁺ generation was linear with respect to the addition of H₂O₂ (0-12 μM). The sensitivity and the detection limit of the proposed Fenton-DPD method for H₂O₂ determination at 551 nm were (2.55 ± 0.01) × 10⁴ M^-1 cm^-1 and 0.05 μM, respectively. The stoichiometric factor for the reaction of H₂O₂ with DPD was 1:1.18. The absorbance of the generated DPD⁺ was found to be stable in different types of water within 20 min. Moreover, the proposed Fenton-DPD method could be used for the analysis of the trace H₂O₂ in rainwater and determine the rate constants that involved H₂O₂ with high accuracy.

Low-dose doxycycline inhibits hydrogen peroxide-induced oxidative stress, MMP-2 up-regulation and contractile dysfunction in human saphenous vein grafts

Background: Cardiopulmonary bypass (CPB) applied during coronary artery bypass grafting (CABG), promotes inflammation, generation of reactive oxygen species (ROS) and up-regulation of matrix metalloproteinases (MMPs). All these complications may lead to contractile dysfunction, restenosis and early graft failure, restricting long-term efficacy of bypass grafts. Low-dose doxycycline is a potent MMP inhibitor and ROS scavenger. In this study, we aimed to investigate the effects of doxycycline on ROS generation, MMP regulation and contractile dysfunction induced by H₂O₂ in human saphenous vein (HSV) grafts. Methods: HSV grafts (n=7) were divided into four groups after removing endothelial layer by mechanical scratching and incubated with 10 µM H₂O₂ and/or 10 µM doxycycline for 16 hrs. Untreated segments served as control. Concentration-response curves to noradrenaline (NA), potassium chloride (KCl), serotonin (5-HT) and papaverine were performed. Superoxide anion and other ROS levels were determined by using lucigenin- and luminol-enhanced chemiluminescence assays, respectively. Expression/activity of gelatinases (MMP-2/MMP-9) was examined by gelatin zymography. MMP-13 expression was evaluated by immunostaining/immunoscoring. Results: H₂O₂ incubation increased superoxide anion and other ROS levels. Doxycycline prevented these increments. H₂O₂ suppressed contractile responses to NA, KCl and 5-HT. Doxycycline ameliorated contractions to NA and KCl but not to 5-HT. H₂O₂ or doxycycline did not altered relaxation to papaverine. MMP-2 and MMP-13 expression increased with H₂O₂, but doxycycline inhibited MMP-2 up-regulation/activation. Conclusion: Low-dose doxycycline may have beneficial effects on increased oxidative stress, MMP up-regulation/activation and contractile dysfunction in HSV grafts.

Non-immunological toxicological mechanisms of metamizole-associated neutropenia in HL60 cells

Metamizole is an analgesic and antipyretic, but can cause neutropenia and agranulocytosis. We investigated the toxicity of the metabolites N-methyl-4-aminoantipyrine (MAA), 4-aminoantipyrine (AA), N-formyl-4-aminoantipyrine (FAA) and N-acetyl-4-aminoantipyrine (AAA) on neutrophil granulocytes and on HL60 cells (granulocyte precursor cell line). MAA, FAA, AA, and AAA (up to 100 µM) alone were not toxic for HL60 cells or granulocytes. In the presence of the myeloperoxidase substrate H₂O₂, MAA reduced cytotoxicity for HL60 cells at low concentrations (<50 µM), but increased cytotoxicity at 100 µM H₂O₂. Neutrophil granulocytes were resistant to H₂O₂ and MAA. Fe²⁺ and Fe³⁺ were not toxic to HL60 cells, irrespective of the presence of H₂O₂ and MAA. Similarly, MAA did not increase the toxicity of lactoferrin, hemoglobin or methemoglobin for HL60 cells. Hemin (hemoglobin degradation product containing a porphyrin ring and Fe³⁺) was toxic on HL60 cells and cytotoxicity was increased by MAA. EDTA, N-acetylcystein and glutathione prevented the toxicity of hemin and hemin/MAA. The absorption spectrum of hemin changed concentration-dependently after addition of MAA, suggesting an interaction between Fe³⁺ and MAA. NMR revealed the formation of a stable MAA reaction product with a reaction pathway involving the formation of an electrophilic intermediate. In conclusion, MAA, the principle metabolite of metamizole, increased cytotoxicity of hemin by a reaction involving the formation of an electrophilic metabolite. Accordingly, cytotoxicity of MAA/hemin could be prevented by the iron chelator EDTA and by the electron donors NAC and glutathione. Situations with increased production of hemin may represent a risk factor for metamizole-associated granulocytopenia.

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.

Redox Changes in Amateur Race Car Drivers Before and After Racing

Despite the unique opportunity race car driving provides to study exercise in extreme conditions, the sport of racing is under-represented. A better understanding of how racing changes physiological measures combined with driver demographics may help reduce driver risks and expand the field of driver science. This study charted the changes in heart rate, body temperature, blood pressure, static oxidation reduction potential (sORP), and antioxidant capacity in drivers before and after racing (n=23). The interaction between racing and driver characteristics on physiological variables were evaluated. Heart rate, body temperature, and sORP were elevated after racing (P<0.05). Age, cockpit temperature, experience, and speed did not correlate with physiological or oxidative measures (P>0.05). Elevated post-race sORP values were associated with higher pre-race systolic blood pressure and lower antioxidant capacity (P<0.05). We conclude that racing alters the redox response in drivers and that drivers' pre-race systolic blood pressure and antioxidant capacity can further alter it. A better understanding of the physical and oxidative changes which result from racing may help minimize the unique risks.

Clinical and Genomic Correlates of Neutrophil Reactive Oxygen Species Production in Pediatric Patients With Crohn's Disease

BACKGROUND & AIMS

Individuals with monogenic disorders of phagocyte function develop chronic colitis that resembles Crohn's disease (CD). We tested for associations between mutations in genes encoding reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, neutrophil function, and phenotypes of CD in pediatric patients.

METHODS

We performed whole-exome sequence analysis to identify mutations in genes encoding NADPH oxidases (such as CYBA, CYBB, NCF1, NCF2, NCF4, RAC1, and RAC2) using DNA from 543 pediatric patients with inflammatory bowel diseases. Blood samples were collected from an additional 129 pediatric patients with CD and 26 children without IBD (controls); we performed assays for neutrophil activation, reactive oxygen species (ROS) production, and bacteria uptake and killing. Whole-exome sequence analysis was performed using DNA from 46 of the children with CD to examine associations with NADPH gene mutations; RNA sequence analyses were performed using blood cells from 46 children with CD to test for variations in neutrophil gene expression associated with ROS production.

RESULTS

We identified 26 missense mutations in CYBA, CYBB, NCF1, NCF2, and NCF4. Patients with CD who carried mutations in these genes were 3-fold more likely to have perianal disease (P = .0008) and stricturing complications (P = .002) than children with CD without these mutations. Among patients with CD with none of these mutations, 9% had undergone abdominal surgery; among patients with mutations in these NADPH oxidase genes, 31% had undergone abdominal surgery (P = .0004). A higher proportion of neutrophils from children with CD had low ROS production (47%) than from controls (15%) among the 129 patients tested for ROS (P = .002). Minor alleles of the NADPH genes were detected in 7% of children with CD whose neutrophils produced normal levels of ROS vs 38% of children whose neutrophils produced low levels of ROS (P = .009). Neutrophils that produced low levels of ROS had specific alterations in genes that regulate glucose metabolism and antimicrobial responses.

CONCLUSIONS

We identified missense mutations in genes that encode NADPH oxidases in children with CD; these were associated with a more aggressive disease course and reduced ROS production by neutrophils from the patients.

Evaluation of the level of dynamic thiol/disulphide homeostasis in adolescent patients with newly diagnosed primary hypertension

BACKGROUND

Thiol/disulphide homeostasis plays a critical role in numerous intracellular enzymatic pathways including antioxidant defense and detoxification. This study was designed to investigate the impact of thiol/disulfide homeostasis in adolescent patients with recently diagnosed primary hypertension (HT) using a novel and automated method.

METHODS

Native thiol/disulphide levels were measured by a novel spectrophotometric method (Cobasc 501, Roche Diagnostics, Mannheim, Germany) in 30 patients with primary HT together with 30 healthy controls.

RESULTS

The levels of native thiol, total thiol, and native thiol/total thiol ratios were significantly lower, while the disulphide level, disulphide/native thiol, and disulphide/total thiol ratios were significantly higher in patients with primary HT compared with the control group. There were significant positive correlations between 24-h mean systolic and diastolic blood pressure and disulphide levels, disulphide/native thiol, and disulphide/total thiol ratios. A multiple linear regression model showed that a disulphide/native thiol ratio above 5 and family history of HT are independent predictors of HT.

CONCLUSIONS

Our study showed that dynamic thiol/disulphide homeostasis shifted towards disulphide formation in adolescent patients with primary HT. Understanding the role of thiol/disulfide homeostasis in primary HT might provide new therapeutic intervention strategies for patients.

Cocaine Exposure Increases Blood Pressure and Aortic Stiffness via the miR-30c-5p-Malic Enzyme 1-Reactive Oxygen Species Pathway

Cocaine abuse increases the risk of cardiovascular mortality and morbidity; however, the underlying molecular mechanisms remain elusive. By using a mouse model for cocaine abuse/use, we found that repeated cocaine injection led to increased blood pressure and aortic stiffness in mice associated with elevated levels of reactive oxygen species (ROS) in the aortas, a phenomenon similar to that observed in hypertensive humans. This ROS elevation was correlated with downregulation of Me1 (malic enzyme 1), an important redox molecule that counteracts ROS generation, and upregulation of microRNA (miR)-30c-5p that targets Me1 expression by directly binding to its 3'UTR (untranslated region). Remarkably, lentivirus-mediated overexpression of miR-30c-5p in aortic smooth muscle cells recapitulated the effect of cocaine on Me1 suppression, which in turn led to ROS elevation. Moreover, in vivo silencing of miR-30c-5p in smooth muscle cells resulted in Me1 upregulation, ROS reduction, and significantly suppressed cocaine-induced increases in blood pressure and aortic stiffness-a similar effect to that produced by treatment with the antioxidant N-acetyl cysteine. Discovery of this novel cocaine-↑miR-30c-5p-↓Me1-↑ROS pathway provides a potential new therapeutic avenue for treatment of cocaine abuse-related cardiovascular disease.

The Future Challenge of Reactive Oxygen Species (ROS) in Hypertension: From Bench to Bed Side

Reactive oxygen species (ROS) act as signaling molecules that control physiological processes, including cell adaptation to stress. Redox signaling via ROS has quite recently become the focus of much attention in numerous pathological contexts, including neurodegenerative diseases, kidney and cardiovascular disease. Imbalance in ROS formation and degradation has also been implicated in essential hypertension. Essential hypertension is characterized by multiple genetic and environmental factors which do not completely explain its associated risk factors. Thereby, even if advances in therapy have led to a significant reduction in hypertension-associated complications, to interfere with the unbalance of redox signals might represent an additional therapeutic challenge. The decrease of nitric oxide (NO) levels, the antioxidant activity commonly found in preclinical models of hypertension and the ability of antioxidant approaches to reduce ROS levels have spurred clinicians to investigate the contribution of ROS in humans. Indeed, particular effort has recently been devoted to understanding how redox signaling may contribute to vascular pathobiology in human hypertension. However, although biomarkers of oxidative stress have been found to positively correlate with blood pressure in preclinical model of hypertension, human data are less convincing. We herein provide an overview of the most relevant mechanisms via which oxidative stress might contribute to the pathophysiology of essential hypertension. Moreover, alternative approaches, which are directed towards improving antioxidant machinery and/or interfering with ROS production, are also discussed.

Leveraging H2 O2 Levels for Biomedical Applications

Hydrogen peroxide (H₂ O₂ )-responsive materials have been employed as drug delivery or diagnostic systems to treat or detect diseases with abnormal oxidative stress. A number of H₂ O₂ -responsive systems have been developed, and they have achieved great progress in controlled drug delivery for disease treatment. However, pathological sites with elevated H₂ O₂ level, such as cancer and inflammation, have their own characteristics; therefore the material structures and the subsequent formulations should be reasonably designed to acquire maximized therapeutic effects. In this progress report, we overview the development of H₂ O₂ -responsive functional groups for constructing H₂ O₂ -responsive formulations, as well as the guidance for designing suitable formulations to treat each specific pathological condition. The challenges and perspectives in this field are also discussed.

Elevation of Oxidative Stress and Decline in Endogenous Antioxidant Defense in Elderly Individuals with Hypertension

INTRODUCTION

Hypertension is becoming an important medical and public health problem all over the world and is the most common disorder of ageing. There is a growing evidence of involvement of vascular oxidative stress in the development of hypertension from animal studies. However, studies on humans with hypertension, particularly in elderly are least and data remained controversial. Moreover, studies in elderly people with hypertension are scarce.

AIM

To investigate the possible role of oxidative stress and antioxidant defense in the pathogenesis of hypertension in elderly.

MATERIALS AND METHODS

A cross-sectional study was conducted on elderly males (n=60) with newly diagnosed hypertension and with normal blood pressure. Oxidative stress and antioxidant status were evaluated by assessing the following parameters: plasma Malondialdehyde (MDA), and antioxidants: Superoxide Dismutase (SOD) activity, reduced Glutathione (GSH), and vitamin C levels; and total Nitric Oxide concentration in plasma (NOx). Difference between groups was determined by using unpaired t-test/Mann-Whitney U test. Bivariate correlation and multiple regression analysis were used to determine the relationship between variables.

RESULTS

A significant rise in plasma MDA (p-value=0.013) and lower levels of endogenous antioxidants: SOD (p-value≤0.001) and GSH (p-value≤0.001) were observed in elderly individuals with hypertension when compared to healthy controls. Though not significant, there was a mean decrease in plasma NOx in hypertensive subjects than normotensive ones. While vitamin C showed no significant difference between two groups. Decrease in GSH (β=-0.398; p-value=0.001) and SOD (β=-0.423; p-value≤0.001) were the significant determinants of hypertension in elderly individuals.

CONCLUSION

Above findings indicate that elevation in oxidative stress and decrease in endogenous antioxidant level may be involved in the pathogenesis of hypertension. However, it remains unclear whether oxidative stress causes or augments hypertension.

Heme Oxygenase-1, a Key Enzyme for the Cytoprotective Actions of Halophenols by Upregulating Nrf2 Expression via Activating Erk1/2 and PI3K/Akt in EA.hy926 Cells

Increasing evidence has demonstrated that heme oxygenase-1 (HO-1) is a key enzyme triggered by cellular stress, exhibiting cytoprotective, antioxidant, and anti-inflammatory abilities. Previously, we prepared a series of novel active halophenols possessing strong antioxidant activities in vitro and in vivo. In the present study, we demonstrated that these halophenols exhibited significant protective effects against H₂O₂-induced injury in EA.hy926 cells by inhibition of apoptosis and ROS and TNF-α production, as well as induction of the upregulation of HO-1, the magnitude of which correlated with their cytoprotective actions. Further experiments which aimed to determine the mechanistic basis of these actions indicated that the halophenols induced the activation of Nrf2, Erk1/2, and PI3K/Akt without obvious effects on the phosphorylation of p38, JNK, or the expression of PKC-δ. This was validated with the use of PD98059 and Wortmannin, specific inhibitors of Erk1/2 and PI3K, respectively. Overall, our study is the first to demonstrate that the cytoprotective actions of halophenols involve their antiapoptotic, antioxidant, and anti-inflammatory abilities, which are mediated by the upregulation of Nrf2-dependent HO-1 expression and reductions in ROS and TNF-α generation via the activation of Erk1/2 and PI3K/Akt in EA.hy926 cells. HO-1 may thus be an important potential target for further research into the cytoprotective actions of halophenols.

Involvement of ENaC in the development of salt-sensitive hypertension

Salt-sensitive hypertension is associated with renal and vascular dysfunctions, which lead to impaired fluid excretion, increased cardiac output, and total peripheral resistance. It is commonly accepted that increased renal sodium handling and plasma volume expansion are necessary factors for the development of salt-induced hypertension. The epithelial sodium channel (ENaC) is a trimeric ion channel expressed in the distal nephron that plays a critical role in the regulation of sodium reabsorption in both normal and pathological conditions. In this mini-review, we summarize recent studies investigating the role of ENaC in the development of salt-sensitive hypertension. On the basis of experimental data obtained from the Dahl salt-sensitive rats, we and others have demonstrated that abnormal ENaC activation in response to a dietary NaCl load contributes to the development of high blood pressure in this model. The role of different humoral factors, such as the components of the renin-angiotensin-aldosterone system, members of the epidermal growth factors family, arginine vasopressin, and oxidative stress mediating the effects of dietary salt on ENaC are discussed in this review to highlight future research directions and to determine potential molecular targets for drug development.