New insights on oxidative stress in the artery wall

Xanthine Oxidoreductase in the Pathogenesis of Endothelial Dysfunction: An Update

Xanthine oxidoreductase (XOR) is a rate-limiting enzyme in the formation of uric acid (UA) and is involved in the generation of reactive oxygen species (ROS). Overproduction of ROS has been linked to the pathogenesis of hypertension, atherosclerosis, and cardiovascular disease, with multiple studies over the last 30 years demonstrating that XOR inhibition is beneficial. The involvement of XOR and its constituents in the advancement of chronic inflammation and ROS, which are responsible for endothelial dysfunction, is the focus of this evidence-based review. An overabundance of XOR products and ROS appears to drive the inflammatory response, resulting in significant endothelium damage. It has also been demonstrated that XOR activity and ED are connected. Diabetes, hypertension, and cardiovascular disease are all associated with endothelial dysfunction. ROS mainly modifies the activity of vascular cells and can be important in normal vascular physiology as well as the development of vascular disease. Suppressing XOR activity appears to decrease endothelial dysfunction, probably because it lessens the generation of reactive oxygen species and the oxidative stress brought on by XOR. Although there has long been a link between higher vascular XOR activity and worse clinical outcomes, new research suggests a different picture in which positive results are mediated by XOR enzymatic activity. Here in this study, we aimed to review the association between XOR and vascular endothelial dysfunction. The prevention and treatment approaches against vascular endothelial dysfunction in atherosclerotic disease.

LOX-1 variants modulate the severity of cardiovascular disease: state of the art and future directions

Atherosclerosis is one of the major causes of cerebral infarction and many other ischemic cardio-cerebrovascular diseases. Although large randomized clinical trials have highlighted the impressive benefits of lipid-lowering therapies, the 50-70% of patients who have achieved their lipid-lowering goal remain at high cardiovascular disease risk. For this reason, there is a need to investigate other markers of atherosclerosis progression. LOX-1 is a scavenger receptor that accepts oxidized low-density lipoproteins as major ligand and internalizes it by endocytosis favoring its retention in subendothelial layer and triggering a wide variety of proatherogenic events. However, other factors such as cytokines, shear stress, and advanced glycation end-products can upregulate LOX-1. LOX-1 is encoded by the OLR1 gene, located in the p12.3-p13 region of chromosome 12. OLR1 gene has different isoforms induced by splicing, or single-nucleotide polymorphisms (SNPs). According to some authors, the expression of these isoforms induces a different effect on atherosclerosis and cardiovascular disease. In particular, LOXIN, an isoform lacking part of the functional domain, exerts an important role in atherosclerosis protection. In other cases, studies on SNPs showed an association with more severe forms, like in the case of 3'UTR polymorphisms. The knowledge of these variants can give rise to the development of new preventive therapies and can lead to the identification of subjects at greater risk of cardiovascular event. In this review, we reported the state of the art regarding SNPs with known effects on OLR1 splicing and how LOX-1 variants modulate the severity of cardiovascular disease.

Insight on Oxygen-Supplying Biomaterials Used to Enhance Cell Survival, Retention, and Engraftment for Tissue Repair

Oxygen is one of the essential requirements for cell survival, retention, and proliferation. The field of regenerative medicine and tissue engineering (TE) has realized considerable achievements for the regeneration of tissues. However, tissue regeneration still lacks the full functionality of solid organ implantations; limited cell survival and retention due to oxidative stress and hypoxia in the deeper parts of tissues remains a perpetual challenge. Especially prior to neovascularization, hypoxia is a major limiting factor, since oxygen delivery becomes crucial for cell survival throughout the tissue-engineered construct. Oxygen diffusion is generally limited in the range 100-200 μm of the thickness of a scaffold, and the cells located beyond this distance face oxygen deprivation, which ultimately leads to hypoxia. Furthermore, before achieving functional anastomosis, implanted tissues will be depleted of oxygen, resulting in hypoxia (<5% dissolved oxygen) followed by anoxic (<0.5% dissolved oxygen) microenvironments. Different types of approaches have been adopted to establish a sustained oxygen supply both in vitro and in vivo. In this review, we have summarized the recent developments in oxygen-generating and/or releasing biomaterials for enhancing cell survival in vitro, as well as for promoting soft and hard tissue repair, including skin, heart, nerve, pancreas, muscle, and bone tissues in vivo. In addition, redox-scavenging biomaterials and oxygenated scaffolds have also been highlighted. The surveyed results have shown significant promise in oxygen-producing biomaterials and oxygen carriers for enhancing cell functionality for regenerative medicine and TE applications. Taken together, this review provides a detailed overview of newer approaches and technologies for oxygen production, as well as their applications for bio-related disciplines.

Trafficking of oxidative stress-generated lipid hydroperoxides: pathophysiological implications

Lipid hydroperoxides (LOOHs) are reactive intermediates that arise during peroxidation of unsaturated phospholipids, glycolipids and cholesterol in biological membranes and lipoproteins. Non-physiological lipid peroxidation (LPO) typically occurs under oxidative stress conditions associated with pathologies such as atherogenesis, neurodegeneration, and carcinogenesis. As key intermediates in the LPO process, LOOHs are susceptible to one-electron versus two-electron reductive turnover, the former exacerbating membrane or lipoprotein damage/dysfunction and the latter diminishing it. A third possible LOOH fate is translocation to an acceptor membrane/lipoprotein, where one- or two-electron reduction may then ensue. In the case of cholesterol (Ch)-derived hydroperoxides (ChOOHs), translocation can be specifically stimulated by StAR family trafficking proteins, which are normally involved in Ch homeostasis and Ch-mediated steroidogenesis. In this review, we discuss how these processes can be impaired by StAR-mediated ChOOH and Ch co-trafficking to mitochondria of vascular macrophages and steroidogenic cells, respectively. The protective effects of endogenous selenoperoxidase, GPx4, are also discussed. This is the first known example of detrimental ChOOH transfer via a natural Ch trafficking pathway and inhibition thereof by GPx4.

Effects of PCSK9 Targeting: Alleviating Oxidation, Inflammation, and Atherosclerosis

Characterized as a chronic inflammatory disease of the large arteries, atherosclerosis is the primary cause of cardiovascular disease, the leading contributor of morbidity and mortality worldwide. Elevated plasma cholesterol levels and chronic inflammation within the arterial plaque are major mediators of plaque initiation, progression, and instability. In 2003, the protein PCSK9 (proprotein convertase subtilisin/kexin 9) was discovered to play a critical role in cholesterol regulation, thus becoming a key player in the mechanisms behind atherosclerotic plaque development. Emerging evidence suggests that PCSK9 could potentially have effects on atherosclerosis that are independent of cholesterol levels. The objective of this review was to discuss the role on PCSK9 in oxidation, inflammation, and atherosclerosis. This function activates proinflammatory cytokine production and affects oxidative modifications within atherosclerotic lesions, revealing its more significant role in atherosclerosis. Although a variety of evidence demonstrates that PCSK9 plays a role in atherosclerotic inflammation, the direct mechanism of involvement is still unknown, driving a gap in knowledge to such a predominant player in cardiovascular disease. Investigation of proteins structurally related to PCSK9 may interestingly be the link in unveiling the mechanistic role of this protein’s involvement in oxidation and inflammation. Importantly, the unique structure of PCSK9 bears structural homology to a one‐of‐a‐kind domain found in the metabolic protein resistin, which is responsible for many of the same inflammatory outcomes as PCSK9. Closing this gap in knowledge of PCSK9`s role in atherosclerotic oxidation and inflammation will provide fundamental information for understanding, preventing, and treating cardiovascular disease.

Аtherosclerosis and cardiovascular risk in patients with inflammatory bowel disease

Inflammatory bowel disease (IBD) can cause early atherosclerosis. There is a correlation between inflammatory activity in IBD and cardiovascular events. Chronic inflammation can lead to endothelial dysfunction. This review discusses the possibilities of the mechanisms underlying the relationship between IBD and atherosclerosis, the role of innate and humoral immunity, intestinal microbiota, biomarkers (C-reactive protein, homocysteine, etc.), as well as the possibility of early instrumental diagnosis of subclinical manifestations of atherosclerosis in patients with IBD by measuring carotid intimamedia thickness and aortic pulse wave velocity. The need for active prevention of cardiovascular diseases in this group of patients is emphasized, including through the control of inflammation activity, as well as the inclusion of IBD in one of the risk factors for cardiovascular diseases.

Influence of Peripheral Transluminal Angioplasty Alongside Exercise Training on Oxidative Stress and Inflammation in Patients with Peripheral Arterial Disease

In patients with intermittent claudication, exercise training ameliorates inflammation by reducing oxidative stress. A total of 41 patients with intermittent claudication (Rutherford 3) were included in the study (with 21 patients treated by endovascular revascularization (ER), and 20 patients without ER). All patients were referred to home-based exercise training. Absolute and initial claudication distance (ACD, ICD) and ABI (ankle–brachial index) were measured. ROS (reactive oxygen species) formation was measured using the luminol analogue L-012. Follow-up was performed after 3 months. ROS production after NOX2 (NAPDH oxidase 2) stimulation showed a significant reduction in both groups at follow-up (PTA group: p = 0.002, control group: p = 0.019), with a higher relative reduction in ROS in the PTA group than in the control group (p = 0.014). ABI measurements showed a significant increase in the PTA (peripheral transluminal angioplasty) group (p = 0.001), but not in the control group (p = 0.127). Comparing both groups at follow-up, ABI was higher in the PTA group (p = 0.047). Both groups showed a significant increas ACD and ICD at follow-up (PTA group: ACD: p = 0.001, ICD: p < 0.0001; control group: ACD: p = 0.041, ICD: p = 0.002). There was no significant difference between both groups at follow-up (ACD: p = 0.421, ICD: p = 0.839). Endovascular therapy in combination with exercise training leads to a lower leukocyte activation state with a reduced NOX2-derived ROS production paralleled by an improved ABI, ACD and ICD. Our data support the strategy to combine exercise training with preceding endovascular therapy.

Pathophysiological potential of lipid hydroperoxide intermembrane translocation: Cholesterol hydroperoxide translocation as a special case

Peroxidation of unsaturated phospholipids, glycolipids, and cholesterol in biological membranes under oxidative stress conditions can underlie a variety of pathological conditions, including atherogenesis, neurodegeneration, and carcinogenesis. Lipid hydroperoxides (LOOHs) are key intermediates in the peroxidative process. Nascent LOOHs may either undergo one-electron reduction to exacerbate membrane damage/dysfunction or two-electron reduction to attenuate this. Another possibility is LOOH translocation to an acceptor site, followed by either of these competing reductions. Cholesterol (Ch)-derived hydroperoxides (ChOOHs) have several special features that will be highlighted in this review. In addition to being susceptible to one-electron vs. two-electron reduction, ChOOHs can translocate from a membrane of origin to another membrane, where such turnover may ensue. Intracellular StAR family proteins have been shown to deliver not only Ch to mitochondria, but also ChOOHs. StAR-mediated transfer of free radical-generated 7-hydroperoxycholesterol (7-OOH) results in impairment of (a) Ch utilization in steroidogenic cells, and (b) anti-atherogenic reverse Ch transport in vascular macrophages. This is the first known example of how a peroxide derivative can be recognized by a natural lipid trafficking pathway with deleterious consequences. For each example above, we will discuss the underlying mechanism of oxidative damage/dysfunction, and how this might be mitigated by antioxidant intervention.

Cardiac hypertrophic risk markers of left ventricle and left atrium in chronic heart failure due to aortic and mitral valve disease

BACKGROUND

Chronic valvular heart disease leads to systolic dysfunction and left atrial enlargement that ultimately results in heart failure.

PURPOSE

To investigate prognostic importance of Echocardiography and plasma natriuretic peptide levels that increase as a compensatory response and can be used as predictive markers for cardiac hypertrophy.

MATERIAL AND METHODS

The patients were divided into three groups: 51 with left ventricle hypertrophy due to aortic valve disease; 126 with left atrial enlargement due to mitral valve dysfunction; and 76 with both conditions. Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) plasma levels were measured in all three respective groups showing dilated cardiomyopathy.

RESULTS

The mean left ventricular end-diastolic dimension at 64.3 ± 1.6 mm (P < 0.00) and left atrial dimension at 58.3 ± 3.7 mm (P < 0.00) were significantly high. However, patients with both conditions showed significantly high values for left ventricular end-diastolic dimension (63.3 ± 3 mm, P < 0.00) and left atrial dimension (54.9 ± 4 mm, P < 0.00) when compared with controls. A significant positive correlation was found between plasma natriuretic peptides levels and dilated cardiomyopathy. The mean values of ANP were 173 ± 46.6 pg/mL (P < 0.00), 140.4 ± 42.4 pg/mL (P < 0.00), and 295.1 ± 67.5 pg/mL (P < 0.00), significantly high in all three respective disease groups. The levels of BNP were also significantly high at 189 ± 44.5 pg/mL (P < 0.00), 166.6 ± 36.6 pg/mL (P < 0.00), and 323 ± 69.1 pg/mL (P < 0.00) in the disease groups with left ventricular hypertrophy, left atrial enlargement, and the disease group showing both characteristics, respectively.

CONCLUSION

Significant positive associations were found between left ventricle hypertrophy and left atrial enlargement with ANP and BNP.

Interface of Phospholipase Activity, Immune Cell Function, and Atherosclerosis

Phospholipases are a family of lipid-altering enzymes that can either reduce or increase bioactive lipid levels. Bioactive lipids elicit signaling responses, activate transcription factors, promote G-coupled-protein activity, and modulate membrane fluidity, which mediates cellular function. Phospholipases and the bioactive lipids they produce are important regulators of immune cell activity, dictating both pro-inflammatory and pro-resolving activity. During atherosclerosis, pro-inflammatory and pro-resolving activities govern atherosclerosis progression and regression, respectively. This review will look at the interface of phospholipase activity, immune cell function, and atherosclerosis.

Acute partial sleep deprivation and high-intensity interval exercise effects on postprandial endothelial function

PURPOSE

Acute-total and chronic-partial sleep deprivation increase the risks for cardiovascular disease (CVD). Cardiovascular function assessed by flow mediated dilation (FMD) is reduced after sleep deprivation. High-intensity interval exercise (HIIE) improves postprandial FMD. Sleep-deprived individuals may practice HIIE followed by a high-fat breakfast. This study investigated the acute-partial sleep deprivation (APSD) and HIIE interaction on postprandial FMD.

METHODS

Fifteen healthy males (age 31 ± 5 years) participated in: (a) reference sleep (~ 9.5 h) with no HIIE (RS), (b) RS and HIIE (RSX), and (c) APSD and HIIE (SSX). HIIE was performed in 3:2 min intervals at 90% and 40% of VO₂ reserve. FMD was assessed the night before (D1), the morning of the next day (D2), 1 h (1hrPE) and 4 h post HIIE (4hrPE).

RESULTS

FMD% change was lower at RS compared to both RSX (F_1,14 = 23.96, p < 0.001, η² = 0.631) and SSX (F_1,14 = 4.8, p = 0.47, η² = 0.253) at 1hrPE. RSX and SSX did not differ at 1hrPE (F_1,14 = 0.2, p = 0.889, η² = 0.001), but SSX elicited greater FDM responses. Absolute FMD change was lower at RS compared to both RSX (F_1,14 = 21.5, p < 0.001, η² = 0.606) and SSX (F_1,14 = 7.01, p = 0.019, η² = 0.336) at 1hrPE. RSX and SSX did not differ at 1hrPE (F_1,14 = .03, p = 0.858, η² = 0.002), but SSX elicited greater FDM responses.

CONCLUSIONS

HIIE short-term effects on cardiovascular function remain cardioprotective even after an acute-partial sleep deprivation.

Adaptations of Escherichia coli strains to oxidative stress are reflected in properties of their structural proteomes

BACKGROUND

The reconstruction of metabolic networks and the three-dimensional coverage of protein structures have reached the genome-scale in the widely studied Escherichia coli K-12 MG1655 strain. The combination of the two leads to the formation of a structural systems biology framework, which we have used to analyze differences between the reactive oxygen species (ROS) sensitivity of the proteomes of sequenced strains of E. coli. As proteins are one of the main targets of oxidative damage, understanding how the genetic changes of different strains of a species relates to its oxidative environment can reveal hypotheses as to why these variations arise and suggest directions of future experimental work.

RESULTS

Creating a reference structural proteome for E. coli allows us to comprehensively map genetic changes in 1764 different strains to their locations on 4118 3D protein structures. We use metabolic modeling to predict basal ROS production levels (ROStype) for 695 of these strains, finding that strains with both higher and lower basal levels tend to enrich their proteomes with antioxidative properties, and speculate as to why that is. We computationally assess a strain's sensitivity to an oxidative environment, based on known chemical mechanisms of oxidative damage to protein groups, defined by their localization and functionality. Two general groups - metalloproteins and periplasmic proteins - show enrichment of their antioxidative properties between the 695 strains with a predicted ROStype as well as 116 strains with an assigned pathotype. Specifically, proteins that a) utilize a molybdenum ion as a cofactor and b) are involved in the biogenesis of fimbriae show intriguing protective properties to resist oxidative damage. Overall, these findings indicate that a strain's sensitivity to oxidative damage can be elucidated from the structural proteome, though future experimental work is needed to validate our model assumptions and findings.

CONCLUSION

We thus demonstrate that structural systems biology enables a proteome-wide, computational assessment of changes to atomic-level physicochemical properties and of oxidative damage mechanisms for multiple strains in a species. This integrative approach opens new avenues to study adaptation to a particular environment based on physiological properties predicted from sequence alone.

GPCR transactivation signalling in vascular smooth muscle cells: role of NADPH oxidases and reactive oxygen species

The discovery and extension of G-protein-coupled receptor (GPCR) transactivation-dependent signalling has enormously broadened the GPCR signalling paradigm. GPCRs can transactivate protein tyrosine kinase receptors (PTKRs) and serine/threonine kinase receptors (S/TKRs), notably the epidermal growth factor receptor (EGFR) and transforming growth factor-β type 1 receptor (TGFBR1), respectively. Initial comprehensive mechanistic studies suggest that these two transactivation pathways are distinct. Currently, there is a focus on GPCR inhibitors as drug targets, and they have proven to be efficacious in vascular diseases. With the broadening of GPCR transactivation signalling, it is therefore important from a therapeutic perspective to find a common transactivation pathway of EGFR and TGFBR1 that can be targeted to inhibit complex pathologies activated by the combined action of these receptors. Reactive oxygen species (ROS) are highly reactive molecules and they act as second messengers, thus modulating cellular signal transduction pathways. ROS are involved in different mechanisms of GPCR transactivation of EGFR. However, the role of ROS in GPCR transactivation of TGFBR1 has not yet been studied. In this review, we will discuss the involvement of ROS in GPCR transactivation-dependent signalling.

Myeloperoxidase inhibition in mice alters atherosclerotic lesion composition

Myeloperoxidase (MPO) is a highly abundant protein within the neutrophil that is associated with lipoprotein oxidation, and increased plasma MPO levels are correlated with poor prognosis after myocardial infarct. Thus, MPO inhibitors have been developed for the treatment of heart failure and acute coronary syndrome in humans. 2-(6-(5-Chloro-2-methoxyphenyl)-4-oxo-2-thioxo-3,4-dihydropyrimidin-1(2H)-yl)acetamide PF-06282999 is a recently described selective small molecule mechanism-based inactivator of MPO. Here, utilizing PF-06282999, we investigated the role of MPO to regulate atherosclerotic lesion formation and composition in the Ldlr^-/- mouse model of atherosclerosis. Though MPO inhibition did not affect lesion area in Ldlr^-/- mice fed a Western diet, reduced necrotic core area was observed in aortic root sections after MPO inhibitor treatment. MPO inhibition did not alter macrophage content in and leukocyte homing to atherosclerotic plaques. To assess non-invasive monitoring of plaque inflammation, [¹⁸F]-Fluoro-deoxy-glucose (FDG) was administered to Ldlr^-/- mice with established atherosclerosis that had been treated with clinically relevant doses of PF-06282999, and reduced FDG signal was observed in animals treated with a dose of PF-06282999 that corresponded with reduced necrotic core area. These data suggest that MPO inhibition does not alter atherosclerotic plaque area or leukocyte homing, but rather alters the inflammatory tone of atherosclerotic lesions; thus, MPO inhibition could have utility to promote atherosclerotic lesion stabilization and prevent atherosclerotic plaque rupture.

Hyperglycemia-Driven Neuroinflammation Compromises BBB Leading to Memory Loss in Both Diabetes Mellitus (DM) Type 1 and Type 2 Mouse Models

End organ injury in diabetes mellitus (DM) is driven by microvascular compromise (including diabetic retinopathy and nephropathy). Cognitive impairment is a well-known complication of DM types 1 and 2; however, its mechanism(s) is(are) not known. We hypothesized that blood-brain barrier (BBB) compromise plays a key role in cognitive decline in DM. Using a DM type 1 model (streptozotocin injected C57BL/6 mice) and type 2 model (leptin knockout obese db/db mice), we showed enhanced BBB permeability and memory loss (Y maze, water maze) that are associated with hyperglycemia. Gene profiling in isolated microvessels from DM type 1 animals demonstrated deregulated expression of 54 genes related to angiogenesis, inflammation, vasoconstriction/vasodilation, and platelet activation pathways by at least 2-fold (including eNOS, TNFα, TGFβ1, VCAM-1, E-selectin, several chemokines, and MMP9). Further, the magnitude of gene expression was linked to degree of cognitive decline in DM type 1 animals. Gene analysis in brain microvessels of DM type 2 db/db animals showed alterations of similar genes as in DM 1 model, some to an even greater extent. Neuropathologic analyses of brain tissue derived from DM mice showed microglial activation, expression of ICAM-1, and attenuated coverage of pericytes compared to controls. There was a significant upregulation of inflammatory genes in brain tissue in both DM models. Taken together, our findings indicate that BBB compromise in DM in vivo models and its association with memory deficits, gene alterations in brain endothelium, and neuroinflammation. Prevention of BBB injury may be a new therapeutic approach to prevent cognitive demise in DM.

Lipoxidation in cardiovascular diseases

Lipids can go through lipid peroxidation, an endogenous chain reaction that consists in the oxidative degradation of lipids leading to the generation of a wide variety of highly reactive carbonyl species (RCS), such as short-chain carbonyl derivatives and oxidized truncated phospholipids. RCS exert a wide range of biological effects due to their ability to interact and covalently bind to nucleophilic groups on other macromolecules, such as nucleic acids, phospholipids, and proteins, forming reversible and/or irreversible modifications and generating the so-called advanced lipoxidation end-products (ALEs). Lipoxidation plays a relevant role in the onset of cardiovascular diseases (CVD), mainly in the atherosclerosis-based diseases in which oxidized lipids and their adducts have been extensively characterized and associated with several processes responsible for the onset and development of atherosclerosis, such as endothelial dysfunction and inflammation. Herein we will review the current knowledge on the sources of lipids that undergo oxidation in the context of cardiovascular diseases, both from the bloodstream and tissues, and the methods for detection, characterization, and quantitation of their oxidative products and protein adducts. Moreover, lipoxidation and ALEs have been associated with many oxidative-based diseases, including CVD, not only as potential biomarkers but also as therapeutic targets. Indeed, several therapeutic strategies, acting at different levels of the ALEs cascade, have been proposed, essentially blocking ALEs formation, but also their catabolism or the resulting biological responses they induce. However, a deeper understanding of the mechanisms of formation and targets of ALEs could expand the available therapeutic strategies.

Association of CYBA gene (-930 A/G and 242 C/T) polymorphisms with oxidative stress in breast cancer: a case-control study

Background

Oxidative stress (OS) is a key characteristic feature in cancer initiation and progression. Among multiple cancers, NADPH oxidase (NOX) dependent free radical production is implicated in oxidative stress. P22phox, a subunit of NADPH oxidase encoded by the CYBA gene has functional polymorphisms associated with various complex diseases. The present study was aimed to examine the importance and association of the functional polymorphisms of CYBA gene (-930 A/G and 242 C/T) with the oxidative stress in breast cancer (BC) development and progression.

Materials and Methods

We have performed a case-control study on 300 breast cancer patients and 300 healthy individuals as controls to examine the role of CYBA gene -930 A/G and 242 C/T single nucleotide polymorphisms (SNPs) using As-PCR and PCR-RFLP assays and its association with OS as measured by plasma MDA levels. Linkage disequilibrium (LD) plots were generated using Haploviewtool and Multifactor dimensionality reduction (MDR) analysis was applied to assess high-order interactions between the SNPs. The Insilco analysis has been performed to predict the effect of SNPs on the gene regulation using online tools.

Results

We have found that genotype frequencies of CYBA gene -930 A/G and 242C/T polymorphism were significantly different between controls and BC patients (p < 0.05). The haplotype combination -930G/242C and -930G/242T were associated with 1.44 & 1.56 folds increased risk for breast cancer respectively. Further, the MDA levels were higher in the patients carrying -930G/242C and -930G/242T haplotype (p < 0.001). Our results have been substantiated by Insilco analysis.

Conclusion

Results of the present study suggest that GG genotype of -930 A/G polymorphism, -930G/242C and -930G/242T haplotypes of CYBA gene polymorphisms have shown association with higher MDA levels in breast cancer patients, signify that elevated oxidative stress might aid in increased risk for breast cancer initiation and progression.

Prognostic Values of Inflammatory and Redox Status Biomarkers on the Risk of Major Lower-Extremity Artery Disease in Individuals With Type 2 Diabetes

OBJECTIVE

Inflammation and oxidative stress play an important role in the pathogenesis of lower-extremity artery disease (LEAD). We assessed the prognostic values of inflammatory and redox status biomarkers on the risk of LEAD in individuals with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Plasma concentrations of tumor necrosis factor-α receptor 1 (TNFR1), angiopoietin-like 2, ischemia-modified albumin (IMA), fluorescent advanced glycation end products, protein carbonyls, and total reductive capacity of plasma were measured at baseline in the SURDIAGENE (Survie, Diabete de type 2 et Genetique) cohort. Major LEAD was defined as the occurrence during follow-up of peripheral revascularization or lower-limb amputation.

RESULTS

Among 1,412 participants at baseline (men 58.2%, mean [SD] age 64.7 [10.6] years), 112 (7.9%) developed major LEAD during 5.6 years of follow-up. High plasma concentrations of TNFR1 (hazard ratio [95% CI] for second vs. first tertile 1.12 [0.62-2.03; P = 0.71] and third vs. first tertile 2.16 [1.19-3.92; P = 0.01]) and of IMA (2.42 [1.38-4.23; P = 0.002] and 2.04 [1.17-3.57; P = 0.01], respectively) were independently associated with an increased risk of major LEAD. Plasma concentrations of TNFR1 but not IMA yielded incremental information, over traditional risk factors, for the risk of major LEAD as follows: C-statistic change (0.036 [95% CI 0.013-0.059]; P = 0.002), integrated discrimination improvement (0.012 [0.005-0.022]; P < 0.001), continuous net reclassification improvement (NRI) (0.583 [0.294-0.847]; P < 0.001), and categorical NRI (0.171 [0.027-0.317]; P = 0.02).

CONCLUSIONS

Independent associations exist between high plasma TNFR1 or IMA concentrations and increased 5.6-year risk of major LEAD in people with type 2 diabetes. TNFR1 allows incremental prognostic information, suggesting its use as a biomarker for LEAD.

Vascular smooth muscle cells activate PI3K/Akt pathway to attenuate myocardial ischemia/reperfusion-induced apoptosis and autophagy by secreting bFGF

BACKGROUND

Vascular smooth muscle cells (VSMCs) has been reported to be implicated in atherosclerotic plaque instability and rupture. Recently, it has been demonstrated that VSMCs block the progression of cardiac remodeling and thus promoting cardiac function in a rat myocardial infarction model. However, the detailed molecular mechanism of how VSMCs contributes to recovery in myocardial ischemia/reperfusion remains not fully understood.

METHODS

We have isolated, identified and cultured VSMCs from rats to co-culture with rat cardiomyocyte H9C2. To culture H9C2 cells under hypoxia, we utilized CoCl₂-containing medium to culture for 8 h and then was replaced with normal media for additional 16 h. Cell viability was examined by MTT assay and apoptosis was determined by flow cytometry. Infarcted area of myocardial tissue was measured by TTC staining.

RESULTS

VSMCs was shown to promote cell viability and inhibit apoptosis of H9C2 cells under hypoxia, which exhibited upregulated anti-apoptotic protein Bcl-2 and autophagy-related protein p62, whereas pro-apoptotic protein cleaved caspase-3 and the level of LC3II/LC3I were downregulated. Then, we confirmed VSMCs played the contributory role in cell viability of H9C2 under hypoxia by secreting bFGF, which exerted its function through PI3K/Akt pathway. Finally, in vivo, the results demonstrated that VSMCs transplantation contributed to recovery of myocardial ischemia.

CONCLUSION

We determine that VSMCs promote recovery of infarcted cardiomyocyte through secretion of bFGF, which then activating PI3K/Akt pathway to inhibit apoptosis and autophagy. These findings provide more insights into the molecular mechanism underlying VSMCs contributing to recovery of myocardial I/R and facilitate developing therapeutical strategies for treating heart diseases.

Evaluation of lipid peroxidation by the analysis of volatile aldehydes in the headspace of synthetic membranes using Selected Ion Flow Tube Mass Spectrometry, SIFT-MS

RATIONALE

Oxidative stress of cell membranes leads to a number of pathological processes associated with some diseases and is accompanied by the release of volatile aldehydes, which, potentially, can be used as biomarkers. Thus, the aim was to investigate peroxidation of defined synthetic membranes by direct quantitative analysis of volatile aldehydes.

METHODS

The concentration spectra of volatile compounds present in the headspace of synthetic membranes under peroxidation stress and following mechanical stress due to sonication were obtained using solid phase microextraction (SPME) in combination with Gas Chromatography Mass Spectrometry (SPME/GC/MS) and Selected Ion Flow Tube Mass Spectrometry (SIFT-MS). The focus was on the direct, real time quantification of volatile aldehydes. In addition, the total aldehydes in the aqueous membrane suspensions were quantified using the TBARS method.

RESULTS

Propanal, butanal, pentanal, hexanal, heptanal and malondialdehyde were detected and quantified in the humid headspace of the media containing the synthetic membranes following peroxidation. The composition and concentration of these saturated aldehydes strongly depend on the unsaturated fatty acids representation in the liposomes. Some protective effect of cholesterol was observed especially for membranes peroxidised by Fenton reagents and after application of a mechanical stress.

CONCLUSIONS

This study demonstrates that peroxidation of model synthetic membranes in vitro can be tracked in real time using direct quantification by SIFT-MS of several specific aldehydes in the headspace of the membrane suspensions. Cholesterol plays an important role in retaining membrane structure and can indirectly protect membranes from lipid peroxidation.

Vascular endothelium dysfunction: a conservative target in metabolic disorders

AIM

Vascular endothelium plays a role in capillary transport of nutrients and drugs and regulates angiogenesis, homeostasis, as well as vascular tone and permeability as a major regulator of local vascular homeostasis. The present study has been designed to investigate the role of endothelium in metabolic disorders.

METHODS

The endothelium maintains the balance between vasodilatation and vasoconstriction, procoagulant and anticoagulant, prothrombotic and antithrombotic mechanisms.

RESULTS

Diabetes mellitus causes the activation of aldose reductase, polyol pathway and advanced glycation-end-product formation that collectively affect the phosphorylation status and expression of endothelial nitric oxide synthatase (eNOS) and causes vascular endothelium dysfunction. Elevated homocysteine levels have been associated with increase in LDL oxidation, generation of hydrogen peroxides, superoxide anions that increased oxidative degradation of nitric oxide. Hyperhomocysteinemia has been reported to increase the endogenous competitive inhibitors of eNOS viz L-N-monomethyl arginine (L-NMMA) and asymmetric dimethyl arginine (ADMA) that may contribute to vascular endothelial dysfunction. Hypercholesterolemia stimulates oxidation of LDL cholesterol, release of endothelins, and generation of ROS. The increased cholesterol and triglyceride level and decreased protective HDL level, decreases the activity and expression of eNOS and disrupts the integrity of vascular endothelium, due to oxidative stress. Hypertension also stimulates release of endothelins, vasoconstrictor prostanoids, angiotensin II, inflammatory cytokines, xanthine oxidase and, thereby, reduces bioavailability of nitric oxide.

CONCLUSION

Thus, the cellular and molecular mechanisms underlying diabetes mellitus, hyperhomocysteinemia, hypercholesterolemia hypertension and hyperuricemia leads to an imbalance of phosphorylation and dephosphorylation status of lipid and protein kinase that cause modulation of vascular endothelial L-arginine/nitric oxide synthetase (eNOS), to produce vascular endothelium dysfunction.

The effects of percutaneous transluminal coronary intervention on biomarkers of oxidative stress in the erythrocytes of elderly male patients

OBJECTIVES

Oxidative stress plays a key role in the pathogenesis of coronary artery disease. The aim of this study was to compare the effects of percutaneous transluminal coronary angioplasty (PTCA) and elective coronary angiography (EC) on erythrocytic antioxidant defense in elderly male patients.

METHODS

Twenty-three stable angina pectoris (SAP) patients undergoing PTCA and 18 patients with ischemic symptoms scheduled to undergo diagnostic EC were included in the study. The concentrations of malondialdehyde (MDA) and reduced glutathione (GSH) and the activities of Zn,Cu-superoxide dismutase (SOD-1), catalase (CAT), and cytosolic glutathione peroxidase (GSH-Px) were examined in the erythrocytes before, immediately after and 2 weeks following PTCA or EC.

RESULTS

The MDA concentrations were significantly higher and SOD-1, CAT, and GSH-Px activities were significantly lower in the PTCA group than in the EC group at baseline. Two weeks after treatment, the activities of the enzymes significantly increased in both groups, whereas the MDA concentrations decreased only in the PTCA patients.

CONCLUSIONS

The results confirm that an advanced state of atherosclerosis is related to greater levels of oxidative stress. The study indicates that both procedures may induce antioxidant defenses; however, PTCA exclusively induces a long-term reduction in lipid peroxidation.

Impact of Oxidative Stress on the Heart and Vasculature: Part 2 of a 3-Part Series

Vascular disease and heart failure impart an enormous burden in terms of global morbidity and mortality. Although there are many different causes of cardiac and vascular disease, most causes share an important pathological mechanism: oxidative stress. In the failing heart, oxidative stress occurs in the myocardium and correlates with left ventricular dysfunction. Reactive oxygen species (ROS) negatively affect myocardial calcium handling, cause arrhythmia, and contribute to cardiac remodeling by inducing hypertrophic signaling, apoptosis, and necrosis. Similarly, oxidative balance in the vasculature is tightly regulated by a wealth of pro- and antioxidant systems that orchestrate region-specific ROS production and removal. Reactive oxygen species also regulate multiple vascular cell functions, including endothelial and smooth muscle cell growth, proliferation, and migration; angiogenesis; apoptosis; vascular tone; host defenses; and genomic stability. However, excessive levels of ROS promote vascular disease through direct and irreversible oxidative damage to macromolecules, as well as disruption of redox-dependent vascular wall signaling processes.

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.

Biological Antioxidant Potential Negatively Correlates With Carotid Artery Intima-Media Thickness

Oxidative stress is a crucial factor in the pathogenesis and development of cardiovascular disease. Recently, simplified methods for the detection of reactive oxygen species (ROS) using the derivatives of reactive oxygen metabolites (d-ROMs) test as an index of ROS products and the biological antioxidant potential (BAP) test as an index of antioxidant potential have been utilized. These methods are easy to perform, quick, inexpensive since they use small equipment, and provide reliable results compared with established oxidative stress and antioxidant markers. Because oxidative stress has been shown to represent the balance of production of ROS and antioxidant capacity, it is more appropriate to evaluate ROS and antioxidant capacity simultaneously. However, no study has examined the associations among d-ROMs, BAP values, and carotid artery intima-media thickness (IMT) concurrently. Therefore, we studied the associations among d-ROMs, BAP values, and the carotid artery IMT. Carotid artery IMT, blood pressure (BP), fasting circulating d-ROMs, BAP, glucose metabolism, lipid, and C-reactive protein levels were measured in 95 subjects (age: 49.5 ± 13.8 years; men: 41; women: 54), including 42 healthy subjects and 53 patients with hypertension, dyslipidemia, and diabetes mellitus who were not on medication. The results of multiple regression analysis revealed that dependent carotid artery IMT determinants remained significantly associated with age, systolic BP, total cholesterol, and BAP, whereas dependent BAP determinants remained significantly associated with body mass index and carotid artery IMT. BAP was strongly correlated with carotid artery IMT in our cohort. Our results suggest that BAP may be a useful risk marker for carotid atherosclerosis.

Multivariate statistical evaluation of trace metal levels in the blood of atherosclerosis patients in comparison with healthy subjects

BACKGROUND

Numerous epidemiological studies have suggested that metal exposure may promote the atherosclerosis disorder in humans.

OBJECTIVE

This study is carried out to assess the distribution, correlation and multivariate apportionment of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), lead (Pb) and zinc (Zn) in the blood of atherosclerosis patients in comparison with healthy donors.

METHOD

The quantification of metals is done by atomic absorption spectrometry, after wet-acid digestion of the blood samples.

RESULTS

Significantly higher concentrations of cadmium, chromium, copper, iron and manganese are found in the blood of atherosclerosis patients. The correlation study shows diverse relationships among the metals in blood of the patients and controls. Multivariate cluster analysis based on the metal levels in patients and controls reveals clearly separate grouping for the patients and healthy donors. Moreover, principal component analysis shows divergent grouping of the metals for the patients and healthy donors, which may be associated with the altered metabolism of the metals in atherosclerosis patients.

CONCLUSION

Overall, the distribution, correlation and multivariate apportionment of selected metals in atherosclerosis patients and healthy donors are significantly divergent. Hence, present findings suggest that the trace and redox metals accumulated in the body may pose a high risk for atherosclerosis development.

Endothelial NADPH oxidase 4 protects ApoE-/- mice from atherosclerotic lesions

Vascular reactive oxygen species (ROS) are known to be involved in atherosclerosis development and progression. NADPH oxidase 4 (Nox4) is a constitutively active ROS-producing enzyme that is highly expressed in the vascular endothelium. Nox4 is unique in its biology and has been implicated in vascular repair, however, the role of Nox4 in atherosclerosis is unknown. Therefore, to determine the effect of endothelial Nox4 on development of atherosclerosis, Apoe E-/- mice +/- endothelial Nox4 (ApoE-/- + EC Nox4) were fed a high cholesterol/high fat (Western) diet for 24 weeks. Significantly fewer atherosclerotic lesions were observed in the ApoE-/- + EC Nox4 mice as compared to the ApoE-/- littermates, which was most striking in the abdominal region of the aorta. In addition, markers of T cell populations were markedly different between the groups; T regulatory cell marker (FoxP3) was increased whereas T effector cell marker (T-bet) was decreased in aorta from ApoE-/- + EC Nox4 mice compared to ApoE-/- alone. We also observed decreased monokine induced by gamma interferon (MIG; CXCL9), a cytokine known to recruit and activate T cells, in plasma and tissue from ApoE-/- + EC Nox4 mice. To further investigate the link between endothelial Nox4 and MIG expression, we utilized cultured endothelial cells from our EC Nox4 transgenic mice and human cells with adenoviral overexpression of Nox4. In these cultured cells, upregulation of Nox4 attenuated endothelial cell MIG expression in response to interferon-gamma. Together these data suggest that endothelial Nox4 expression reduces MIG production and promotes a T cell distribution that favors repair over inflammation, leading to protection from atherosclerosis.

Oxidized LDL induces phosphorylation of non-muscle myosin IIA heavy chain in macrophages

Oxidized LDL (oxLDL) performs critical roles in atherosclerosis by inducing macrophage foam cell formation and promoting inflammation. There have been reports showing that oxLDL modulates macrophage cytoskeletal functions for oxLDL uptake and trapping, however, the precise mechanism has not been clearly elucidated. Our study examined the effect of oxLDL on non-muscle myosin heavy chain IIA (MHC-IIA) in macrophages. We demonstrated that oxLDL induces phosphorylation of MHC-IIA (Ser1917) in peritoneal macrophages from wild-type mice and THP-1, a human monocytic cell line, but not in macrophages deficient for CD36, a scavenger receptor for oxLDL. Protein kinase C (PKC) inhibitor-treated macrophages did not undergo the oxLDL-induced MHC-IIA phosphorylation. Our immunoprecipitation revealed that oxLDL increased physical association between PKC and MHC-IIA, supporting the role of PKC in this process. We conclude that oxLDL via CD36 induces PKC-mediated MHC-IIA (Ser1917) phosphorylation and this may affect oxLDL-induced functions of macrophages involved in atherosclerosis.

Impairment of Macrophage Cholesterol Efflux by Cholesterol Hydroperoxide Trafficking: Implications for Atherogenesis Under Oxidative Stress

OBJECTIVE

Oxidative stress associated with cardiovascular disease can produce various oxidized lipids, including cholesterol oxides, such as 7-hydroperoxide (7-OOH), 7-hydroxide (7-OH), and 7-ketone (7=O). Unlike 7=O and 7-OH, 7-OOH is redox active, giving rise to the others via potentially toxic-free radical reactions. We tested the novel hypothesis that under oxidative stress conditions, steroidogenic acute regulatory (StAR) family proteins not only deliver cholesterol to/into mitochondria of vascular macrophages, but also 7-OOH, which induces peroxidative damage that impairs early stage reverse cholesterol transport.

APPROACH AND RESULTS

Stimulation of human monocyte-derived THP-1 macrophages with dibutyryl-cAMP resulted in substantial upregulation of StarD1 and ATP-binding cassette (ABC) transporter, ABCA1. Small interfering RNA-induced StarD1 knockdown before stimulation had no effect on StarD4, but reduced ABCA1 upregulation, linking the latter to StarD1 functionality. Mitochondria in stimulated StarD1-knockdown cells internalized 7-OOH slower than nonstimulated controls and underwent less 7-OOH-induced lipid peroxidation and membrane depolarization, as probed with C11-BODIPY (4,4-difluoro-5-(4-phenyl-1,3-butadienyl)-4-bora-3a,4a-diaza-s-inda-cene-3-undecanoic acid) and JC-1 (5,5',6,6'-tetrachloro-1,1',3,3'-tetraethyl-benzimidazolylcarbocyanine iodide), respectively. Major functional consequences of 7-OOH exposure were (1) loss of mitochondrial CYP27A1 activity, (2) reduced 27-hydroxycholesterol (27-OH) output, and (3) downregulation of cholesterol-exporting ABCA1 and ABCG1. Consistently, 7-OOH-challenged macrophages exported less cholesterol to apoA-I or high-density lipoprotein than did nonchallenged controls. StarD1-mediated 7-OOH transport was also found to be highly cytotoxic, whereas 7=O and 7-OH were minimally toxic.

CONCLUSIONS

This study describes a previously unrecognized mechanism by which macrophage cholesterol efflux can be incapacitated under oxidative stress-linked disorders, such as chronic obesity and hypertension. Our findings provide new insights into the role of macrophage redox damage/dysfunction in atherogenesis.

THP1 macrophages oxidized cholesterol, generating 7-derivative oxysterols specifically released by HDL

Macrophages are well recognized as key pathophysiologic agents in many chronic inflammatory diseases, especially atherosclerosis. During atherogenesis process, low density lipoproteins (LDL) undergo oxidation (oxLDL) and become highly atherogenic as they induce a strong accumulation of cholesterol in subendothelial macrophages leading to the formation of foam cells, the major cellular component of fatty streaks. OxLDL are enriched in oxidation products of cholesterol called oxysterols involved in the regulation of cholesterol homeostasis, by their ability to induce cellular oxidative stress and cytotoxicity. Little is known about intracellular oxysterol production in macrophages. Using both radiochemical and mass analyzes, we showed that THP1 macrophages promote the intracellular oxidation of LDL derived-cholesterol as well as intracellular cholesterol, this later mechanism being enhanced by exposure with native or oxLDL. We demonstrated that in both THP1 and Raw 267.4 cells cholesterol oxidation occurs in the late endosomal compartment. Most oxysterols were produced by non-enzymatic routes (7-ketocholesterol and 7α/β-hydroxycholesterol) but enzymatically formed 7α-, 27-hydroxycholesterol were also quantified. Incubation of THP1 macrophages with nLDL or oxLDL, induced a 2- and 100-fold increase in oxysterol production, respectively. Both oxysterols derived from LDL cholesterol and cellular cholesterol were readily exported to HDL whereas apoA1 was inefficient, showing that HDL plays a major role in the removal of excess oxysterols in THP1 macrophages.

Metabolomics reveals impaired maturation of HDL particles in adolescents with hyperinsulinaemic androgen excess

Hyperinsulinaemic androgen excess (HIAE) in prepubertal and pubertal girls usually precedes a broader pathological phenotype in adulthood that is associated with anovulatory infertility, metabolic syndrome and type 2 diabetes. The metabolic derangements that determine these long-term health risks remain to be clarified. Here we use NMR and MS-based metabolomics to show that serum levels of methionine sulfoxide in HIAE girls are an indicator of the degree of oxidation of methionine-148 residue in apolipoprotein-A1. Oxidation of apo-A1 in methionine-148, in turn, leads to an impaired maturation of high-density lipoproteins (HDL) that is reflected in a decline of large HDL particles. Notably, such metabolic alterations occur in the absence of impaired glucose tolerance, hyperglycemia and hypertriglyceridemia, and were partially restored after 18 months of treatment with a low-dose combination of pioglitazone, metformin and flutamide.

Deficient zinc levels and myocardial infarction : association between deficient zinc levels and myocardial infarction: a meta-analysis

The purpose of this study is to clarify the association between Zn levels and myocardial infarction (MI) using a meta-analysis approach. We searched articles in the PubMed, OVID, and ScienceDirect published as of November 2014. Thirteen eligible articles with 2886 subjects from 41 case-control studies were identified. Overall, pooled analysis indicated that subjects with MI had lower Zn levels than healthy controls (standardized mean difference (SMD) = -1.848, 95 % confidence interval (CI) = [-2.365, -1.331]). Further subgroup analysis found that subjects with MI had lower Zn levels than healthy controls in serum (SMD = -1.764, 95 % CI = [-2.417, -1.112]) and hair (SMD = -3.326, 95 % CI = [-4.616, -2.036]), but not in toenail (SMD = -0.396, 95 % CI = [-1.114, 0.322]). The subgroup analysis stratified by type of Zn measurement found a similar pattern in inductively coupled plasma-atomic absorption spectrometry (ICP-AAS) (SMD = -2.442, 95 % CI = [-3.092, -1.753]), but not in neutron activation analysis (NAA) (SMD = -0.449, 95 % CI = [-1.127, 0.230]). Lower Zn levels in MI patients were found both in male (SMD = -3.350, 95 % CI = [-4.531, -2.169]) and female (SMD = -2.681, 95 % CI = [-3.440, -1.922]). And the difference of Zn levels according to MI in Asia (SMD = -2.555, 95 % CI = [-3.267, -1.844]) was greater to that among the population in Europe (SMD = -0.745, 95 % CI = [-1.386, -0.104]), but no difference was found in Oceania (SMD = -0.255, 95 % CI = [-0.600, 0.089]). In conclusion, this meta-analysis indicates that there is a significant association between Zn deficiency and MI. We suggest that a community-based, long-term observation in a cohort design should be performed to obtain better understanding of causal relationships between Zn and MI, through measuring hair Zn at baseline to investigate whether the highest zinc category versus lowest was associated with MI risk.

Change of walking distance in intermittent claudication: impact on inflammation, oxidative stress and mononuclear cells: a pilot study

BACKGROUND

Atherosclerosis is a chronic inflammatory process involving the immune system and formation of reactive oxygen species (ROS). We investigated changes of mononuclear blood cells and ROS production in relation to the walking distance of patients with intermittent claudication during home-based exercise training.

METHODS

Forty patients with intermittent claudication were asked to perform a home-based exercise training for a mean time of 12 months. ROS formation was measured using the luminol analogue L-012. Peripheral blood leucocytes [monocytes, polymorphonuclear neutrophils (PMN) and dendritic cells (DC)] were analysed by flow cytometry and analysed for the expression of major inflammatory surface molecules.

RESULTS

At follow-up, patients showed an increased walking distance and reduced ROS production upon stimulation with a phorbol ester derivative (PDBu) (p < 0.01). Monocytes changed their inflammatory phenotype towards an increased anti-inflammatory CD14(++)CD16(-) subpopulation (p < 0.0001). Adhesion molecules CD11b, CD11c and TREM-1 on monocytes and PMN decreased (all p < 0.01). On DC expression of HLA-DR, CD86 or CD40 decreased at follow-up. Inflammatory markers like fibrinogen, C-reactive protein or soluble TREM-1 (sTREM-1) decreased over the observation period. Finally, we found a close relation of sTREM-1 with the walking distance, fibrinogen and ROS production.

CONCLUSIONS

We observed an amelioration of the proinflammatory phenotype on monocytes, DC and PMN, as well as a reduced ROS production in PAD patients under home-based exercise, paralleled by an increased walking distance. Our data suggest that a reduced inflammatory state might be achieved by regular walking exercise, possibly in a dimension proportionately to changes in walking distance.

ROS-responsive microspheres for on demand antioxidant therapy in a model of diabetic peripheral arterial disease

A new microparticle-based delivery system was synthesized from reactive oxygen species (ROS)-responsive poly(propylene sulfide) (PPS) and tested for "on demand" antioxidant therapy. PPS is hydrophobic but undergoes a phase change to become hydrophilic upon oxidation and thus provides a useful platform for ROS-demanded drug release. This platform was tested for delivery of the promising anti-inflammatory and antioxidant therapeutic molecule curcumin, which is currently limited in use in its free form due to poor pharmacokinetic properties. PPS microspheres efficiently encapsulated curcumin through oil-in-water emulsion and provided sustained, on demand release that was modulated in vitro by hydrogen peroxide concentration. The cytocompatible, curcumin-loaded microspheres preferentially targeted and scavenged intracellular ROS in activated macrophages, reduced in vitro cell death in the presence of cytotoxic levels of ROS, and decreased tissue-level ROS in vivo in the diabetic mouse hind limb ischemia model of peripheral arterial disease. Interestingly, due to the ROS scavenging behavior of PPS, the blank microparticles also showed inherent therapeutic properties that were synergistic with the effects of curcumin in these assays. Functionally, local delivery of curcumin-PPS microspheres accelerated recovery from hind limb ischemia in diabetic mice, as demonstrated using non-invasive imaging techniques. This work demonstrates the potential for PPS microspheres as a generalizable vehicle for ROS-demanded drug release and establishes the utility of this platform for improving local curcumin bioavailability for treatment of chronic inflammatory diseases.

Catalytic antioxidant therapy by metallodrugs: lessons from metallocorroles

This article provides a perspective on the utility of metal-based catalytic antioxidants for disease prevention or treatment, with focus on their mode of action and its dependence (DCA) or independence (ICA) on the involvement of cofactors.

Chlamydia pneumoniae and oxidative stress in cardiovascular disease: state of the art and prevention strategies

Chlamydia pneumoniae, a pathogenic bacteria responsible for respiratory tract infections, is known as the most implicated infectious agent in atherosclerotic cardiovascular diseases (CVDs). Accumulating evidence suggests that C. pneumoniae-induced oxidative stress may play a critical role in the pathogenesis of CVDs. Indeed, the overproduction of reactive oxygen species (ROS) within macrophages, endothelial cells, platelets and vascular smooth muscle cells (VSMCs) after C. pneumoniae exposure, has been shown to cause low density lipoprotein oxidation, foam cell formation, endothelial dysfunction, platelet adhesion and aggregation, and VSMC proliferation and migration, all responsible for the typical pathological changes of atherosclerotic plaque. The aim of this review is to improve our insight into C. pneumoniae-induced oxidative stress in order to suggest potential strategies for CVD prevention. Several antioxidants, acting on multi-enzymatic targets related to ROS production induced by C. pneumoniae, have been discussed. A future strategy for the prevention of C. pneumoniae-associated CVDs will be to target chlamydial HSP60, involved in oxidative stress.

Vitamin E supplementation in chemical colorectal carcinogenesis: a two-edged knife

This work investigated the effects of Vitamin E (VE) on aberrant crypt foci (ACF) incidence, oxidative stress parameters (serum and hepatic VE concentration, and homocysteine, glutathione (GSH), and malondialdehyde (MDA) levels), and expression of both cyclooxygenase-2 (COX2) and proliferating cellular nuclear antigen (PCNA) in experimental colorectal carcinogenesis. Male Wistar rats received subcutaneous injections of 1,2-dimethylhydrazine (DMH) twice a week, for two weeks (40 mg/kg), except for the Control group. Animals were separated into groups that received different amounts of VE in the diet: 0 IU (0×), 75 IU (recommended daily intake, RDI), 225 IU (3× RDI), or 1500 IU (20× RDI), during (dDMH) or after (aDMH) administration of carcinogen. The 0×dDMH and 3×dDMH groups showed decreased serum VE levels. Hepatic VE concentration was higher in 3×aDMH as compared with the other groups. All the groups, except the Control and the 0×aDMH groups, had reduced GSH levels. The 0×dDMH, 0×aDMH, and 20×aDMH groups exhibited increased MDA levels. The aDMH groups had higher ACF incidence and PCNA expression. The 0×aDMH group presented higher ACF rate, followed by 20×aDMH. Moreover, the 3×aDMH group displayed reduced ACF incidence and COX2 expression. Multivariate analysis revealed that GSH modulated homocysteine levels and COX2. These results suggested that 1500 IU of VE is hazardous, whereas 225 IU of VE has beneficial effects on chemical colorectal carcinogenesis.

Lipid profiling following intake of the omega 3 fatty acid DHA identifies the peroxidized metabolites F4-neuroprostanes as the best predictors of atherosclerosis prevention

The anti-atherogenic effects of omega 3 fatty acids, namely eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) are well recognized but the impact of dietary intake on bioactive lipid mediator profiles remains unclear. Such a profiling effort may offer novel targets for future studies into the mechanism of action of omega 3 fatty acids. The present study aimed to determine the impact of DHA supplementation on the profiles of polyunsaturated fatty acids (PUFA) oxygenated metabolites and to investigate their contribution to atherosclerosis prevention. A special emphasis was given to the non-enzymatic metabolites knowing the high susceptibility of DHA to free radical-mediated peroxidation and the increased oxidative stress associated with plaque formation. Atherosclerosis prone mice (LDLR^−/−) received increasing doses of DHA (0, 0.1, 1 or 2% of energy) during 20 weeks leading to a dose-dependent reduction of atherosclerosis (R² = 0.97, p = 0.02), triglyceridemia (R² = 0.97, p = 0.01) and cholesterolemia (R² = 0.96, p<0.01). Targeted lipidomic analyses revealed that both the profiles of EPA and DHA and their corresponding oxygenated metabolites were substantially modulated in plasma and liver. Notably, the hepatic level of F₄-neuroprostanes, a specific class of DHA peroxidized metabolites, was strongly correlated with the hepatic DHA level. Moreover, unbiased statistical analysis including correlation analyses, hierarchical cluster and projection to latent structure discriminate analysis revealed that the hepatic level of F₄-neuroprostanes was the variable most negatively correlated with the plaque extent (p<0.001) and along with plasma EPA-derived diols was an important mathematical positive predictor of atherosclerosis prevention. Thus, oxygenated n-3 PUFAs, and F₄-neuroprostanes in particular, are potential biomarkers of DHA-associated atherosclerosis prevention. While these may contribute to the anti-atherogenic effects of DHA, further in vitro investigations are needed to confirm such a contention and to decipher the molecular mechanisms of action.

Correlation of Waist-to-hip Ratio (WHR) and Oxidative Stress in Patients of Acute Myocardial Infarction (AMI)

BACKGROUND

Obesity is associated with increased oxidative stress and lipid peroxidation is thought to play a crucial role in the generation of atherosclerotic lesions of Acute Myocardial Infarction (AMI).

METHODS

The case-control study contained 120 subjects divided in two groups, 60 patients with AMI and equal number of age- and sex-matched healthy subjects as controls. Ratio of Waist Circumference (WC) to Hip Circumference (HC) (waist-to-hip ratio) of all the subjects was recorded. Antioxidant status of the individuals was determined by measuring the serum levels of Glutathione Peroxidase (GPx) and Superoxide Dismutase (SOD). Estimation of Malondialdehyde (MDA), a marker of lipid peroxidation was used as a surrogate marker of free radical activity.

RESULTS

WHR was found to be significantly higher in patients of AMI as compared to controls. MDA levels were significantly high and antioxidants molecules GPx and SOD were significantly decreased in AMI patients as compared with control (p<0.001). WHR correlated positively to serum level of MDA and inversely to the serum level of antioxidant enzymes.

CONCLUSION

High Waist-to-hip ratio is associated with high concentrations of malondialdehyde level and low concentration of antioxidant's enzyme. This results in increased oxidative stress, a major causative factor of AMI.

Macrophage mitochondrial damage from StAR transport of 7-hydroperoxycholesterol: implications for oxidative stress-impaired reverse cholesterol transport

StAR family proteins in vascular macrophages participate in reverse cholesterol transport (RCT). We hypothesize that under pathophysiological oxidative stress, StARs will transport not only cholesterol to macrophage mitochondria, but also pro-oxidant cholesterol hydroperoxides (7-OOHs), thereby impairing early-stage RCT. Upon stimulation with dibutyryl-cAMP, RAW264.7 macrophages exhibited a strong time-dependent induction of mitochondrial StarD1 and plasma membrane ABCA1, which exports cholesterol. 7α-OOH uptake by stimulated RAW cell mitochondria (like cholesterol uptake) was strongly reduced by StarD1 knockdown, consistent with StarD1 involvement. Upon uptake by mitochondria, 7α-OOH (but not redox-inactive 7α-OH) triggered lipid peroxidation and membrane depolarization while reducing ABCA1 upregulation. These findings provide strong initial support for our hypothesis.

Critical limb ischaemia is characterised by an increased production of whole blood reactive oxygen species and expression of TREM-1 on neutrophils

BACKGROUND

Atherosclerosis is a chronic inflammatory process involving polymorphonuclear neutrophils (PMN) and formation of reactive oxygen species (ROS). The aim of the present study was to investigate the phenotype of inflammatory cells in regard to the expression of triggering receptor expressed on myeloid cells (TREM)-1 and its soluble form (sTREM-1) as well as its relationship with oxidative stress in peripheral artery disease (PAD) patients.

METHODS

In total 90 patients with PAD (N = 30 intermittent claudication (IC) > 300 m absolute walking distance, N = 30 IC < 300 m absolute walking distance, N = 30 critical limb ischaemia (CLI)) and 30 control persons were included. ROS formation was measured at basal or stimulated conditions using the luminol analogue L-012 chemiluminescence. Peripheral blood leucocytes were analysed from whole blood by flow cytometry using different gating strategies to identify PMN and monocytes and analyse TREM-1 expression.

RESULTS

CLI patients showed a significant higher ROS production at basal levels (p < 0.05) and upon stimulation with PDBu (p < 0.0001), LPS (p < 0.05) and zymosan A (p < 0.0001). TREM-1 was expressed significantly more on PMN of CLI patients (p < 0.01) in comparison to all other groups, whereas monocytic expression of TREM-1 was similar between all 4 groups. The serum concentration of its soluble form sTREM-1 however was increased in CLI and IC < 300 m patients (p < 0.0001). sTREM-1 concentrations correlated with basal ROS levels as wells with ROS production upon stimulation. Furthermore, we found the walking distance of IC patients to inversely correlate with sTREM-1 (rs = - 0.29; p = 0.03).

CONCLUSIONS

We found an increased oxidative stress as well as an increased expression of TREM-1 and serum levels of sTREM-1 in patients with CLI. IC < 300 m patients showed a similar patter in regard to oxidative stress, TREM-1 expression and sTREM-1 concentration. Thus, sTREM-1 might represent a potential inflammatory biomarker to evaluate the severity of PAD. Whether this implies the potential for therapeutic recommendations, i.e. conservative vs. interventional/operative treatment, or a possibility to monitor the efficacy of interventions, requires further studies.

Bis(monoacylglycero)phosphate reduces oxysterol formation and apoptosis in macrophages exposed to oxidized LDL

Atherosclerosis is a major cardiovascular complication of diseases associated with increased oxidative stress that favors oxidation of circulating low density lipoproteins (LDLs). Oxidized LDL (oxLDL) is considered as highly atherogenic as it induces a strong accumulation of cholesterol in subendothelial macrophages leading to the formation of foam cells and emergence of atherosclerotic plaque. OxLDL is enriched in oxidation products of cholesterol called oxysterols, some of which have been involved in the ability of oxLDL to induce cellular oxidative stress and cytotoxicity, mainly by apoptosis. Little is known about the possible contribution of cell-generated oxysterols toward LDL-associated oxysterols in cellular accumulation of oxysterols and related apoptosis. Using both radiochemical and mass analyzes, we showed that oxLDL greatly enhanced oxysterol production by RAW macrophages in comparison with unloaded cells or cells loaded with native LDL. Most oxysterols were produced by non-enzymatic routes (7-ketocholesterol and 7α/β-hydroyxycholesterol) but enzymatically formed 7α-, 25- and 27-hydroxycholesterol were also quantified. Bis(monoacylglycero)phosphate (BMP) is a unique phospholipid preferentially found in late endosomes. We and others have highlighted the role of BMP in the regulation of intracellular cholesterol metabolism/traffic in macrophages. We here report that cellular BMP accumulation was associated with a significantly lower production of oxysterols upon oxLDL exposure. Of note, potent pro-apoptotic 7-ketocholesterol was the most markedly decreased. OxLDL-induced cell cytotoxicity and apoptosis were consistently attenuated in BMP-enriched cells. Taken together, our data suggest that BMP exerts a protective action against the pro-apoptotic effect of oxLDL via a reduced production of intracellular pro-apoptotic oxysterols.