Age- and gender-related oxidative status determined in healthy subjects by means of OXY-SCORE, a potential new comprehensive index

OXY-SCORE and Volatile Anesthetics: A New Perspective of Oxidative Stress in EndoVascular Aneurysm Repair-A Randomized Clinical Trial

An aortic aneurysm (AA) is a life-threatening condition. Oxidative stress may be a common pathway linking multiple mechanisms of an AA, including vascular inflammation and metalloproteinase activity. Endovascular aneurysm repair (EVAR) is the preferred surgical approach for AA treatment. During surgery, inflammation and ischemia-reperfusion injury occur, and reactive oxygen species (ROS) play a key role in their modulation. Increased perioperative oxidative stress is associated with higher postoperative complications. The use of volatile anesthetics during surgery has been shown to reduce oxidative stress. Individual biomarkers only partially reflect the oxidative status of the patients. A global indicator of oxidative stress (OXY-SCORE) has been validated in various pathologies. This study aimed to compare the effects of the main volatile anesthetics, sevoflurane and desflurane, on oxidative status during EVAR. Eighty consecutive patients undergoing EVAR were randomized into two groups: sevoflurane and desflurane. Plasma biomarkers of oxidative damage (protein carbonylation and malondialdehyde) and antioxidant defense (total thiols, glutathione, nitrates, superoxide dismutase, and catalase activity) were measured before surgery and 24 h after EVAR. The analysis of individual biomarkers showed no significant differences between the groups. However, the OXY-SCORE was positive in the desflurane group (indicating a shift towards antioxidants) and negative in the sevoflurane group (favoring oxidants) (p < 0.044). Compared to sevoflurane, desflurane had a positive effect on oxidative stress during EVAR. The OXY-SCORE could provide a more comprehensive perspective on oxidative stress in this patient population.

The 24-h profile of the DNA repair enzyme 8-oxoguanine glycosylase 1 (OGG1) is associated with age, TNF-α, and waist circumference in healthy adults

It is unknown how the DNA repair enzyme OGG1 relates to healthy aging in humans, in particular to inflammaging, that is associated with increased levels of TNF-α. This study aimed (1) to investigate how 24-h profiles for OGG1 change during healthy aging and (2) to analyze the relationship of OGG1 with TNF-α, central body fat, cortisol and oxidative DNA/RNA damage. In a cross-sectional study in 20 healthy older and 20 young women, salivary levels of OGG1, TNF-α, cortisol and oxidative DNA/RNA damage were quantified by ELISAs every 4 h for a 24-h period. Trunk circumferences were taken as measures of central body fat. Older women, compared to young women, exhibited significantly lower protein levels of OGG1 throughout the whole 24-h period, a 2.5 times lower 24-h mean level for OGG1 (P < 0.00001) and loss of 24-h variation of OGG1. Both age groups demonstrated significant 24-h variation for TNF-alpha, cortisol and oxidative damage. The 24-h mean level for TNF-α was more than twice as high in older compared to young women (P = 0.011). Regression analysis detected that age, TNF-α and waist circumference were negative significant predictors of OGG1, explaining 56% of variance of OGG1 (P < 0.00001), while levels of cortisol and oxidative damage were no predictors of OGG1. Results indicate a strong decrease of protein levels of OGG1 and a loss of 24-h variation during natural cellular aging. The negative relationship, found between OGG1 and TNF-α and between OGG1 and waist circumference, suggests involvement of proinflammatory processes in DNA repair.

Albumin Redox Modifications Promote Cell Calcification Reflecting the Impact of Oxidative Status on Aortic Valve Disease and Atherosclerosis

Calcific aortic valve disease (CAVD) and coronary artery disease (CAD) are related cardiovascular diseases in which common mechanisms lead to tissue calcification. Oxidative stress plays a key role in these diseases and there is also evidence that the redox state of serum albumin exerts a significant influence on these conditions. To further explore this issue, we used multimarker scores (OxyScore and AntioxyScore) to assess the global oxidative status in patients with CAVD, with and without CAD, also evaluating their plasma thiol levels. In addition, valvular interstitial cells were treated with reduced, oxidized, and native albumin to study how this protein and its modifications affect cell calcification. The differences we found suggest that oxidative status is distinct in CAVD and CAD, with differences in redox markers and thiol levels. Importantly, the in vitro interstitial cell model revealed that modified albumin affects cell calcification, accelerating this process. Hence, we show here the importance of the redox system in the development of CAVD, emphasizing the relevance of multimarker scores, while also offering evidence of how the redox state of albumin influences vascular calcification. These data highlight the relevance of understanding the overall redox processes involved in these diseases, opening the door to new studies on antioxidants as potential therapies for these patients.

Effects of the real-life metal(oid)s mixture on female reproductive function: Less is different

The current study aimed to examine the effect of toxic metal(oid) mixtures (lead (Pb), cadmium (Cd), arsenic (As), mercury (Hg), cadmium (Cd), chromium (Cr), and nickel (Ni)) on female reproductive function in Wistar rats after the 28- and 90-day exposure to dose levels calculated on the basis of the previously conducted human study. Experimental groups included: 2 controls (28- and 90-day), treated groups - doses based on: median- F2 (28) and F2(90) and 95th percentile concentrations in the general human population - F3(28) and F3(90); calculated lower Benchmark dose confidence limit (BMDL) for effects on hormone levels - F1(28) and F1(90) and a group given the doses calculated on the basis of the reference values from the literature (F4(28)). Blood and ovarian samples were collected for sex hormones and ovary redox status analysis. After 28-day exposure, changes were present both in prooxidants and antioxidants. However, after the 90-day exposure redox status imbalance was majorly caused by the disturbance of antioxidants. Changes in some parameters were observed even after exposure to the lowest doses. After 28-day exposure, the strongest dose-response relationship was found between hormones: LH and FSH and toxic metal(oid)s and, after 90-day exposure, between investigated redox status parameters: sulfhydryl groups, ischemia-modified albumin and nuclear factor erythroid 2-related factor 2 (Nrf2) and toxic metal(oid)s. Low obtained BMDLs and narrow Benchmark intervals for toxic metal(oid)s and some of the parameters might confirm the "no-threshold" paradigm. This study indicates possible detrimental effects of prolonged exposure to real-life mixtures of toxic metal(oid) on female reproductive function.

Analysis of the Prognostic Potential of Schlafen 11, Programmed Death Ligand 1, and Redox Status in Colorectal Cancer Patients

The Schlafen 11 (SLFN11) protein has recently emerged as pivotal in DNA damage conditions, with predictive potential for tumor response to cytotoxic chemotherapies. Recent discoveries also showed that the programmed death ligand 1 (PD-L1) protein can be found on malignant cells, providing an immune evasion mechanism exploited by different tumors. Additionally, excessive generation of free radicals, redox imbalance, and consequential DNA damage can affect intestinal cell homeostasis and lead to neoplastic transformation. Therefore, our study aimed to investigate the significance of SLFN11 and PD-L1 proteins and redox status parameters as prognostic biomarkers in CRC patients. This study included a total of 155 CRC patients. SLFN11 and PD-L1 serum levels were measured with ELISA and evaluated based on redox status parameters, sociodemographic and clinical characteristics, and survival. The following redox status parameters were investigated: spectrophotometrically measured superoxide dismutase (SOD), sulfhydryl (SH) groups, advanced oxidation protein products (AOPP), malondialdehyde (MDA), pro-oxidant-antioxidant balance (PAB), and superoxide anion (O2•-). The prooxidative score, antioxidative score, and OXY-SCORE were also calculated. The results showed significantly shorter survival in patients with higher OXY-SCOREs and higher levels of serum SLFN11, while only histopathology-analysis-related factors showed significant prognostic value. OXY-SCORE and SLFN11 levels may harbor prognostic potential in CRC patients.

Principal component analysis of the oxidative stress, inflammation, and dyslipidemia influence in patients with different levels of glucoregulation

Background

The aim of the study was to explore the mutual relationship between oxidative stress, inflammation and metabolic biomarkers in subjects with prediabetes (PRE), newly diagnosed type 2 diabetes patients (NT2D) and overt type 2 diabetes (T2D) using principal component analysis (PCA) as a thorough statistical approach.

Methods

Glycated hemoglobin, lipid parameters, inflammation (IL-6, CRP and fibrinogen) and oxidative stress markers pro-oxidants (AOPP, PAB, TOS) and antioxidants (PON1, tSHG, TAS) were measured. PCA was applied to explore the factors that the most strongly influenced glucoregulation.

Results

A total of 278 subjects were (i.e., 37 PRE, 42 NT2D and 99 T2D) were compared with 100 healthy subjects as a control group (CG). PCA emphasized 4 different factors explaining 49% of the variance of the tested parameters: oxidative stress-dyslipidemia related factor (with positive loading of TG and tSHG, and with negative loading of HDL-c and TAS), dyslipidaemia related factor (i.e., total cholesterol and LDL-c, both with positive loading), Anthropometric related factor (i.e., waist and hip circumference, both with positive loading) and oxidative stressInflammation related factor (i.e., PAB, fibrinogen, and CRP all with positive loading). Out of these 4 factors, only oxidative stress - dyslipidaemia related factor showed a significant predictive capability towards poor glucoregulation. An increase in this factor by one unit showed a 1.6 times higher probability for poor glucoregulation.

Conclusions

Redox imbalance (determined with lower TAS and higher tSHG), in addition to higher TG and lower HDLc was associated with poor glucoregulation.

Association of octacosanol supplementation with redox status in patients on chronic statin therapy

Background

The uneven lipid-lowering statin effects and statin intolerance raise interest regarding the involvement of coadministration of statins and dietary supplements. This study aimed to evaluate the effects of octacosanol supplementation on markers of redox status in cardiovascular patients on chronic atorvastatin therapy.

Methods

A double-blind, randomized, placebo-controlled, single-centre study was conducted. Redox status homeostasis parameters [i.e., advanced oxidation protein products (AOPP), pro-oxidant-antioxidant balance (PAB), total oxidant status (TOS), total antioxidant status (TAS), superoxide dismutase activity (SOD), total protein sulfhydryl (SHgroups), and paraoxonase 1 (PO N 1) activity] were assessed in 81 patients. According to favorable changes in lipid profile, patients were classified into two groups: responders (n = 35) and non-responders (n = 46), and followed for 13 weeks. A principal component analysis (PCA) was applied to explore the effect of octacosanol supplementation and the relationship between investigated parameters as predictors of responders' and non-responders' status.

Results

Significant decrease in Oxy-score value was found at the endpoint compared to baseline in responders' group (21.0 (13.4-25.5) versus 15.1 (12.4-18.0); P < 0.01). PCA analysis extracted 4 significant factors in the both groups, whereas extracted factors containing "octacosanol status" variable explained 14.7% and 11.5% of the variance in responders' and non-responders' subgroups, respectively.

Conclusions

Octacosanol supplementation leads to an improvement of lipid profile and markers of redox status in responders' group. New studies are needed to validate our results in order to find the best approach for personalized supplementation as a useful adjunct to standard statin therapy.

Inflammageing and Cardiovascular System: Focus on Cardiokines and Cardiac-Specific Biomarkers

The term "inflammageing" was introduced in 2000, with the aim of describing the chronic inflammatory state typical of elderly individuals, which is characterized by a combination of elevated levels of inflammatory biomarkers, a high burden of comorbidities, an elevated risk of disability, frailty, and premature death. Inflammageing is a hallmark of various cardiovascular diseases, including atherosclerosis, hypertension, and rapid progression to heart failure. The great experimental and clinical evidence accumulated in recent years has clearly demonstrated that early detection and counteraction of inflammageing is a promising strategy not only to prevent cardiovascular disease, but also to slow down the progressive decline of health that occurs with ageing. It is conceivable that beneficial effects of counteracting inflammageing should be most effective if implemented in the early stages, when the compensatory capacity of the organism is not completely exhausted. Early interventions and treatments require early diagnosis using reliable and cost-effective biomarkers. Indeed, recent clinical studies have demonstrated that cardiac-specific biomarkers (i.e., cardiac natriuretic peptides and cardiac troponins) are able to identify, even in the general population, the individuals at highest risk of progression to heart failure. However, further clinical studies are needed to better understand the usefulness and cost/benefit ratio of cardiac-specific biomarkers as potential targets in preventive and therapeutic strategies for early detection and counteraction of inflammageing mechanisms and in this way slowing the progressive decline of health that occurs with ageing.

The Role of Oxidative Stress in Acute Ischemic Stroke-Related Thrombosis

Acute ischemic stroke is a serious life-threatening disease that affects almost 600 million people each year throughout the world with a mortality of more than 10%, while two-thirds of survivors remain disabled. However, the available treatments for ischemic stroke are still limited to thrombolysis and/or mechanical thrombectomy, and there is an urgent need for developing new therapeutic target. Recently, intravascular oxidative stress, derived from endothelial cells, platelets, and leukocytes, has been found to be tightly associated with stroke-related thrombosis. It not only promotes primary thrombus formation by damaging endothelial cells and platelets but also affects thrombus maturation and stability by modifying fibrin components. Thus, oxidative stress is expected to be a novel target for the prevention and treatment of ischemic stroke. In this review, we first discuss the mechanisms by which oxidative stress promotes stroke-related thrombosis, then summarize the oxidative stress biomarkers of stroke-related thrombosis, and finally put forward an antithrombotic therapy targeting oxidative stress in ischemic stroke.

Overweight and obesity in polycystic ovary syndrome: association with inflammation, oxidative stress and dyslipidaemia

Polycystic ovary syndrome (PCOS) is associated with altered lipid profile and increased small, dense LDL particles (sdLDL). Considering that paraoxonase 1 (PON1) is an antioxidative enzyme located on HDL particles, the aim of this study was to investigate the connection between oxidative stress (OS) and PON1 activity with lipoprotein subclasses in PCOS depending on obesity. In 115 PCOS patients, lipoprotein subclasses distributions were determined by gradient gel electrophoresis. OS status was assessed by total oxidative status (TOS), advanced oxidation protein products, malondialdehyde (MDA), prooxidant-antioxidant balance (PAB), total antioxidative status (TAS) and superoxide dismutase (SOD) and PON1 activity. Overweight/obese PCOS patients (n 55) had increased OS compared with normal weight patients (n 60). In addition, overweight/obese group had lower HDL size and higher proportion of HDL 3a subclasses (P < 0·05). PAB was in negative correlation with HDL 2a (P < 0·001), whereas MDA and SOD correlated positively with HDL 3 subclasses (P < 0·05). Serum PON1 activity was positively associated with proportions of PON1 activity on HDL 2b (P < 0·05) and 2a (P < 0·01), but negatively with the proportion on HDL 3 particles (P < 0·01). LDL B phenotype patients had increased TAS, SOD and PON1 activity on HDL 2b, but decreased PON1 activity on HDL 3 subclasses. OS is associated with altered lipoprotein subclasses distribution in PCOS patients. Obesity in PCOS affects the profile of HDL subclasses, reflected through the reduced proportion of PON1 activity on HDL 3 subclasses in the presence of sdLDL particles.

Low-lead doses induce oxidative damage in cardiac tissue: Subacute toxicity study in Wistar rats and Benchmark dose modelling

Exposure to toxic metals, including lead (Pb), were found as important risk factor for cardiovascular diseases. The aim of the study was to simulate low-level subacute Pb exposure scenario and to determine redox status, redox scores (OXY-score, damage score and protective score) and copper (Cu), zinc (Zn), iron (Fe) and manganese (Mn) levels in cardiac tissue of Wistar rats. Based on the obtained results we have established dose-toxic response relationship and derived Benchmark dose. The male Wistar rats were divided in seven groups (n = 6), six threated groups that received 0.1; 0.5; 1; 3; 7; 15 mg Pb/kg body weight/day for 28 days, by oral gavage and control group. The results of the presented study demonstrated that Pb affect cardiac tissue by inducing production of superoxide anion radical (O₂^.-) and consequently raising malondialdehyde (MDA) levels. The positive trend in OXY-score and damage score were determined. Effect size analysis showed that the main toxic effects were oxidative damage and elevation of MDA. The lowest BMD was calculated for MDA (2.2e-0.6 mg Pb/kg b.w./day). Obtained BMD may be useful in further assessing point of departure in the human health risks assessment of low-level Pb exposure scenario.

Do low molecular weight antioxidants contribute to the Protection against oxidative damage? The interrelation between oxidative stress and low molecular weight antioxidants based on data from the MARK-AGE study

A redox steady state is important in maintaining vital cellular functions and is therefore homeostatically controlled by a number of antioxidative agents, the most important of which are enzymes. Oxidative Stress (OS) is associated with (or/and caused by) excessive production of damaging reactive oxygen and/or nitrogen species (ROS, RNS), which play a role in many pathologies. Because OS is a risk factor for many diseases, much effort (and money) is devoted to early diagnosis and treatment of OS. The desired benefit of the "identify (OS) and treat (by low molecular weight antioxidants, LMWA)" approach is to enable selective treatment of patients under OS. The present work aims at gaining understanding of the benefit of the antioxidants based on interrelationship between the concentration of different OS biomarkers and LMWA. Both the concentrations of a variety of biomarkers and of LMWA were previously determined and some analyses have been published by the MARK-AGE team. For the sake of simplicity, we assume that the concentration of an OS biomarker is a linear function of the concentration of a LMWA (if the association is due to causal relationship). A negative slope of this dependence (and sign of the correlation coefficient) can be intuitively expected for an antioxidant, a positive slope indicates that the LMWA is pro-oxidative, whereas extrapolation of the OS biomarker to [LMWA] = 0 is an approximation of the concentration of the OS biomarker in the absence of the LMWA. Using this strategy, we studied the effects of 12 LMWA (including tocopherols, carotenoids and ascorbic acid) on the OS status, as observed with 8 biomarkers of oxidative damage (including malondialdehyde, protein carbonyls, 3-nitrotyrosine). The results of this communication show that in a cross-sectional study the LMWA contribute little to the redox state and that different "antioxidants" are very different, so that single LMWA treatment of OS is not scientifically justified assuming our simple model. In view of the difficulty of quantitating the OS and the very different effects of various LMWA, the use of the "identify and treat" approach is questionable.

Effects of age and gender on the redox homeostasis of morbidly obese people

Obesity is a chronic disease of complex etiology. Recent evidence suggests that obesity is caused by inflammation of adipose tissue leading to metabolic disorders, cardiovascular disease and cancer. This is the first study to evaluated the effects of age and gender on redox homeostasis, glutathione metabolism, and oxidative damage to plasma/serum lipids and proteins in morbidly obese patients. The study included 120 (60 men and 60 women) morbidly obese patients with class 3 obesity (BMI > 40 kg/m2), classified into three groups depending on age: 20-39 years (n = 20), 40-59 years (n = 20) and 60 years or older (n = 20). The number of patients was calculated a priori based on our previous experiment. We observed a reduction in serum activity of antioxidant enzymes (↓SOD) and plasma concentration of non-enzymatic antioxidants (↓GSH) in obese patients compared to the lean controls, which further decreased with age. Redox status (↑TAC, ↑TOS and ↓OSI) in morbidly obese men and women was shifted towards oxidation. Moreover, lipid (↑MDA and ↑LOOH) and protein (↑AOPP, ↑AGE and ↑Amadori products) damage products of oxidation and nitrosylation/nitration (↑total NO, ↑S-nitrosothiols, ↑peroxynitrite and ↑nitrotyrosine) were elevated in both genders of morbidly obese patients and were higher in the elderly. Interestingly, the concentrations of oxidative and nitrosative stress markers were generally higher in obese men compared to obese women at the same age. Summarizing, we showed that the total antioxidant/oxidant potential of obese patients is significantly increased and shifted towards oxidation. Obese patients have increased lipid and protein oxidation, glycation and nitration as compared to the lean controls. Disturbances in redox homeostasis increase with age in obese patients. Oxidative and nitrosative stress are more intense in men than in women at the same age.

Diurnal relationship between core clock gene BMAL1, antioxidant SOD1 and oxidative RNA/DNA damage in young and older healthy women

BACKGROUND AND OBJECTIVES

BMAL1 is a core clock gene that positively regulates circadian rhythms. In animals, BMAL1 further acts as transcription factor for the SOD1 gene which encodes the major antioxidant enzyme superoxide dismutase. SOD1 protects against oxidative damage that is a major factor for human aging. Mice lacking mBmal1 exhibit premature aging phenotypes which might be related to a reduced expression of SOD1. The purpose of this study was to explore the circadian relationship between BMAL1, SOD1, oxidative RNA/DNA damage and aging in healthy humans.

SUBJECTS AND METHODS

In a cross-sectional study design, buccal mucosa cells and saliva samples were obtained from 21 young (23.7 ± 2.3 yrs) and 21 older women (66.8 ± 5.7 yrs) within 24 h at 4-h intervals (08:00, 12:00, 16:00, 20:00, 24:00 and 04:00 h). Transcript levels of BMAL1 and SOD1 were measured by real-time quantitative PCR. Protein levels of SOD1 were determined by immunoblotting and densitometry. Levels of oxidative RNA/DNA damage and melatonin were quantified by enzyme immunosorbent assays.

RESULTS

Transcript levels of BMAL1 and SOD1 mRNAs as well as protein levels of SOD1 and melatonin exhibited significant 24-h variation in each age group (P < 0.010, Friedman tests). The mRNA expression patterns of BMAL1 and SOD1 showed similar 24-h rhythmicity and positive relationships were found. Strongest relationships occurred in young women at 12:00 h (rs = 0.81, P = 0.005) and in older women at 08:00 h (r = 0.84, P < 0.001). Maximum levels of SOD1 mRNA appeared within 24 h in both age groups at 24:00 h. In both age groups, the timing of maximum level for SOD1 protein was delayed relative to the timing of maximum level for SOD1 mRNA. This delay was larger in older women (8 h) compared to young women (4 h). Older women showed higher oxidative RNA/DNA damage at all time-points compared to young women (P < 0.020). The oxidative RNA/DNA damage decreased continuously from 08:00 to 20:00 h (P < 0.001) in both age groups. Although oxidative damage and SOD1 protein levels declined simultaneously, only weak and non-significant relationships were noted.

CONCLUSIONS

This study demonstrates that transcript levels of SOD1 and protein level of SOD1 follow a circadian pattern of expression in healthy young and older women. The time-shift found between the 24-h maximum levels of SOD1 mRNA and SOD1 protein could be explained by the time needed for translation of SOD1 protein. The positive relationship found between expression levels of SOD1 mRNA and BMAL1 mRNA is in line with animal studies showing that BMAL1 acts as transcription factor and regulates the circadian synthesis of SOD1 mRNA. Differences between young and older women found in the timing of 24-h maxima as well as differences observed in 24-h relationships between characters might be due to age-related alterations in the circadian system. Absence of relationships between levels of SOD1 and oxidative RNA/DNA damage argue for a more complex interaction between the antioxidant system and the circadian system.

The Impact of Oxidative Stress in Human Pathology: Focus on Gastrointestinal Disorders

Accumulating evidence shows that oxidative stress plays an essential role in the pathogenesis and progression of many diseases. The imbalance between the production of reactive oxygen species (ROS) and the antioxidant systems has been extensively studied in pulmonary, neurodegenerative cardiovascular disorders; however, its contribution is still debated in gastrointestinal disorders. Evidence suggests that oxidative stress affects gastrointestinal motility in obesity, and post-infectious disorders by favoring the smooth muscle phenotypic switch toward a synthetic phenotype. The aim of this review is to gain insight into the role played by oxidative stress in gastrointestinal pathologies (GIT), and the involvement of ROS in the signaling underlying the muscular alterations of the gastrointestinal tract (GIT). In addition, potential therapeutic strategies based on the use of antioxidants for the treatment of inflammatory gastrointestinal diseases are reviewed and discussed. Although substantial progress has been made in identifying new techniques capable of assessing the presence of oxidative stress in humans, the biochemical-molecular mechanisms underlying GIT mucosal disorders are not yet well defined. Therefore, further studies are needed to clarify the mechanisms through which oxidative stress-related signaling can contribute to the alteration of the GIT mucosa in order to devise effective preventive and curative therapeutic strategies.

The Interplay between Oxidative Stress, Exercise, and Pain in Health and Disease: Potential Role of Autonomic Regulation and Epigenetic Mechanisms

Oxidative stress can be induced by various stimuli and altered in certain conditions, including exercise and pain. Although many studies have investigated oxidative stress in relation to either exercise or pain, the literature presents conflicting results. Therefore, this review critically discusses existing literature about this topic, aiming to provide a clear overview of known interactions between oxidative stress, exercise, and pain in healthy people as well as in people with chronic pain, and to highlight possible confounding factors to keep in mind when reflecting on these interactions. In addition, autonomic regulation and epigenetic mechanisms are proposed as potential mechanisms of action underlying the interplay between oxidative stress, exercise, and pain. This review highlights that the relation between oxidative stress, exercise, and pain is poorly understood and not straightforward, as it is dependent on the characteristics of exercise, but also on which population is investigated. To be able to compare studies on this topic, strict guidelines should be developed to limit the effect of several confounding factors. This way, the true interplay between oxidative stress, exercise, and pain, and the underlying mechanisms of action can be revealed and validated via independent studies.

OXY-SCORE: a new perspective for left ventricular hypertrophy diagnosis

Background:

A recently developed global indicator of oxidative stress (OXY-SCORE), by combining individual plasma biomarkers of oxidative damage and antioxidant capacity, has been validated in several pathologies, but not in left ventricular hypertrophy (LVH). The aim of this study was to design and calculate a plasma oxidative stress global index for patients with LVH.

Methods:

A total of 70 consecutive adult patients were recruited in our institution and assigned to one of the two study groups (control group/LVH group) by an echocardiography study. We evaluated plasmatic biomarkers of oxidative damage (malondialdehyde and thiolated proteins) and antioxidant defense (total thiols, reduced glutathione, total antioxidant capacity, catalase, and superoxide dismutase activities) by spectrophotometry/fluorimetry in order to calculate a plasma oxidative stress global index (OXY-SCORE) in relation to LVH.

Results:

The OXY-SCORE exhibited a highly significant difference between the groups (p < 0.001). The area under the receiver operating characteristic curve was 0.74 (95% confidence interval (CI), 0.62–0.85; p < 0.001). At a cut-off value of −1, the 68.6% sensitivity and 68.6% specificity values suggest that OXY-SCORE could be used to screen for LVH. A multivariable logistic regression model showed a positive association (p = 0.001) between OXY-SCORE and LVH [odds ratio = 0.55 (95% CI, 0.39–0.79)], independent of gender, age, smoking, glucose, systolic and diastolic arterial pressure, dyslipidemia, estimated glomerular filtration rate, body mass index, and valvular/coronary disease.

Conclusion:

OXY-SCORE could help in the diagnosis of LVH and could be used to monitor treatment response.

Conventional and innovative methods to assess oxidative stress biomarkers in the clinical cardiovascular setting

Oxidative stress has a pivotal and widely described role in the onset and progression of atherosclerotic plaque and cardiovascular disease. Many oxidative stress-related biomarkers can be measured in biological samples; however, there are still many aspects that limit the adoption of oxidative stress assessment in clinical laboratory practice. Here, we report an overview of the different sources and main common oxidative stress biomarkers relevant for cardiovascular physiopathology, describing in detail a recently proposed lipidomic assay for ceramide assessment, as a promising future development in oxidative stress evaluation among the many available redox-related tests.

Oxidative Stress Indexes for Diagnosis of Health or Disease in Humans

Oxidative stress (OS) is the imbalance between oxidant and antioxidant molecules, in favor of oxidants, that causes aging and disease. Many studies have been published that demonstrate the relationship between OS and human health and disease; however, the following questions arise: (i) how are we sure that the OS is present in a biological process? (ii) Is the OS reported in the different investigations equivalent? (iii) What are the best oxidant and antioxidant markers for OS diagnosis? (iv) Can we establish the types and the intensity of the OS? (v) Does OS index could be useful for research and/or application in clinical medicine? In this regard, several indexes have been proposed to measure OS in humans relative to the state of health and disease, among which the following can be highlighted: Oxidative Stress Index (OSI), Tiol Ratios (-SH/TT, -SS/-SH, and-SS/TT), Glutathione Ratio (GSSG/GSH), Oxidative Stress Score (OSS), and OXY-index. Therefore, the aim of this review is to present the state of the art of knowledge about OS indexes for diagnosis of health or disease in humans. We searched for articles in English or Spanish in the PubMed/MEDLINE and Scopus electronic databases published up until May 2019. The keywords used were “oxidative stress,” “index,” and “oxidative stress index.” It was identified 11479 records in both databases, and 490 articles were analyzed. Our review suggests that all indexes analyzed allow diagnose and differentiate the OS related to human health and disease. Also, the studies on OSI, Oxy-score, and OSS indexes have proven to be reliable, practical, and with clinical utility. However, it is necessary to continue with longitudinal studies, especially assess the usefulness of the indexes in the clinical prognosis, and make comparative studies between the different indexes.

Endocan and a novel score for dyslipidemia, oxidative stress and inflammation (DOI score) are independently correlated with glycated hemoglobin (HbA1c) in patients with prediabetes and type 2 diabetes

INTRODUCTION

We aimed to examine serum endocan level and the summary involvement of dyslipidemia, oxidative stress (OS) and inflammation by calculation of its comprehensive score (i.e. Dyslipidemia-Oxy-Inflammation (DOI) score) in relation to glucoregulation in subjects with prediabetes and overt type 2 diabetes (T2D).

MATERIAL AND METHODS

A total of 59 patients with prediabetes and 102 patients with T2D were compared with 117 diabetes-free controls. Glycated hemoglobin (HbA1c), inflammation, OS and lipid parameters were measured. Associations of clinical data with HbA1c level were tested with univariate and multivariate logistic ordinal regression analysis. HbA1c as a dependent variable is given at the ordinal level (i.e. < 5.7%; 5.7-6.4%, > 6.4%, respectively).

RESULTS

Endocan was significantly higher in the T2D group than in the controls. As endocan concentration rose by 1 unit, the probability for higher HbA1c concentration increased by more than 3 times (OR = 3.69, 95% CI: 1.84-7.01, p < 0.001). Also, a rise in the dyslipidemia score, oxy score, inflammation score and DOI score by 1 unit increased the probability of higher HbA1c concentration by 19%, 13%, 51% and 11%, respectively. In the models, after adjustment for confounding variables, endocan and DOI score remained independent predictors of HbA1c level.

CONCLUSIONS

Endocan and DOI score are independently correlated with HbA1c in patients with prediabetes and overt T2D.

Approaches and Methods to Measure Oxidative Stress in Clinical Samples: Research Applications in the Cancer Field

Reactive oxygen species (ROS) are common by-products of normal aerobic cellular metabolism and play important physiological roles in intracellular cell signaling and homeostasis. The human body is equipped with antioxidant systems to regulate the levels of these free radicals and maintain proper physiological function. However, a condition known as oxidative stress (OS) occurs, when ROS overwhelm the body's ability to readily detoxify them. Excessive amounts of free radicals generated under OS conditions cause oxidative damage to proteins, lipids, and nucleic acids, severely compromising cell health and contributing to disease development, including cancer. Biomarkers of OS can therefore be exploited as important tools in the assessment of disease status in humans. In the present review, we discuss different approaches used for the evaluation of OS in clinical samples. The described methods are limited in their ability to reflect on OS only partially, revealing the need of more integrative approaches examining both pro- and antioxidant reactions with higher sensitivity to physiological/pathological alternations. We also provide an overview of recent findings of OS in patients with different types of cancer. Identification of OS biomarkers in clinical samples of cancer patients and defining their roles in carcinogenesis hold great promise in promoting the development of targeted therapeutic approaches and diagnostic strategies assessing disease status. However, considerable data variability across laboratories makes it difficult to draw general conclusions on the significance of these OS biomarkers. To our knowledge, no adequate comparison has yet been performed between different biomarkers and the methodologies used to measure them, making it difficult to conduct a meta-analysis of findings from different groups. A critical evaluation and adaptation of proposed methodologies available in the literature should therefore be undertaken, to enable the investigators to choose the most suitable procedure for each chosen biomarker.

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.

Toxic Effect of Acute Cadmium and Lead Exposure in Rat Blood, Liver, and Kidney

Background: Cadmium and lead are widespread and non-biodegradable pollutants of great concern to human health. In real life scenarios, we are exposed to mixtures of chemicals rather than single chemicals, and it is therefore of paramount importance to assess their toxicity. In this study, we investigated the toxicity of Cd and Pb alone and as a mixture in an animal model of acute exposure. Methods: Experimental groups received a single treatment of aqueous solution of Cd-chloride (15 and 30 mg/kg body weight (b.w.) and Pb-acetate (150 mg/kg b.w.), while the mixture group received 15 mg Cd/kg b.w. and 150 mg Pb/kg b.w. Toxic effects of individual metals and their mixture were investigated on hematological and biochemical parameters, and the redox status in the plasma, liver, and kidneys of treated Wistar rats. Results: Tissue-specific changes were recorded in various parameters of oxidative damage, while the accumulation of metals in tissues accompanied the disturbances of both hematological and biochemical parameters. It was observed that the level of toxic metals in tissues had a different distribution pattern after mixture and single exposure. Conclusions: Comprehensive observations suggest that exposure to Cd and Pb mixtures produces more pronounced effects compared to the response observed after exposure to single metal solutions. However, further research is needed to confirm toxicokinetic or toxicodynamic interactions between these two toxic metals in the organisms.

Evaluation of a Summary Score for Dyslipidemia, Oxidative Stress and Inflammation (the Doi Score) in Women with Polycystic Ovary Syndrome and its Relationship with Obesity

BACKGROUND

Polycystic ovary syndrome (PCOS) is a cardiometabolic disorder whose features include dyslipidemia, increased oxidative stress (OS, oxy) and chronic inflammation. The aim of this study was to investigate the ability of a summary score for dyslipidemia, OS and inflammation (the DOI score) to discriminate PCOS patients from healthy individuals and to evaluate the effect of obesity on individual scores and the DOI score in patients.

METHODS

Lipid status parameters, OS status parameters (advanced oxidation protein products; total oxidative status; prooxidant-antioxidant balance; malondialdehyde; total protein sulphydryl groups and paraoxonase 1 activity) and CRP were measured in 114 patients and 50 controls using standardised assays. The DOI score was calculated as the sum of dyslipidemia, oxy and inflammation scores, determined as Z-score values for every subject in relation to the controls.

RESULTS

PCOS patients had significantly higher oxy-score compared to controls (P<0.001). In addition, the DOI score was significantly higher in PCOS patients (P<0.001) as the dyslipidemia (P<0.05) and inflammatory scores (P<0.001) were greater. According to ROC analysis, the oxy-score showed better diagnostic accuracy in discriminating PCOS patients compared to the DOI score (AUC>0.9, P<0.01). Furthermore, obesity affected the risk scores in patients, especially the DOI score (significantly higher DOI scores in such patients, P<0.001).

CONCLUSION

PCOS patients had greater dyslipidemia, chronic inflammation and OS compared to controls and could be segregated using all four scores. Our data suggest that weight gain could be the common factor responsible for induction and propagation of dyslipidemia, OS and inflammation in PCOS patients.

Oxidative stress in chronic lymphocytic leukemia: still a matter of debate

There is a large body of evidence showing a strong correlation between carcinogenesis of several types of human tumors, including chronic lymphocytic leukemia (CLL), and oxidative stress (OS). The mechanisms by which OS may promote cancer pathogenesis have not been completely deciphered yet and, in CLL, as in other neoplasms, whether OS is a primary cause or simply a downstream effect of the disease is still an open question. It has been demonstrated that, in CLL, OS concomitantly results from increased reactive oxygen species (ROS) production, mainly ascribable to CLL cells mitochondrial activity, and impaired antioxidant defenses. Interestingly, OS evaluation in CLL patients, at diagnosis, seems to have a prognostic significance, thus getting new insights in the biological comprehension of the disease with potential therapeutic implications.

Association of Dyslipidemia, Oxidative Stress, and Inflammation With Redox Status in VLDL, LDL, and HDL Lipoproteins in Patients With Renal Disease

Some cardiovascular complications in patients with chronic kidney disease and end-stage renal disease may be caused by structurally and functionally modified lipoproteins. Redox status (advanced oxidation protein products [AOPPs]), prooxidant–antioxidant balance, total protein sulfhydryl (SH-groups), and paraoxonase 1 (PON1) activity were assessed in 77 renal patients and 20 controls. Lipoproteins were isolated using ultracentrifugation. PON1, PON3, and pentraxin-3 concentration were determined by enzyme-linked immunosorbent assay (ELISA). Dyslipidemia-Oxy-Inflammation (DOI) score was calculated as a sum of dyslipidemia, oxidative stress, and inflammation scores. The dyslipidemia score ( P < .001), oxy score ( P < .01), inflammation score (P < .001), and the DOI score ( P < .001) were higher in patient groups compared with controls. The very-low-density lipoprotein (VLDL) fraction contained the highest amount of AOPP ( P < .001) compared with other lipoprotein fractions in all groups. The low-density lipoprotein (LDL) fraction contained elevated AOPP in all groups compared with the high-density lipoprotein (HDL) fraction ( P < .001). Significant positive correlation was observed between AOPP in LDL fraction and DOI score (ρ = 0.510, P < .01). Dyslipidemia, oxidative stress, and inflammation play an interactive role in renal disease and are mutually associated with redox status in VLDL, LDL, and HDL lipoproteins in plasma of renal patients.

Effect of Oxidative Stress on Cardiovascular System in Response to Gravity

Long-term habitation in space leads to physiological alterations such as bone loss, muscle atrophy, and cardiovascular deconditioning. Two predominant factors—namely space radiation and microgravity—have a crucial impact on oxidative stress in living organisms. Oxidative stress is also involved in the aging process, and plays important roles in the development of cardiovascular diseases including hypertension, left ventricular hypertrophy, and myocardial infarction. Here, we discuss the effects of space radiation, microgravity, and a combination of these two factors on oxidative stress. Future research may facilitate safer living in space by reducing the adverse effects of oxidative stress.

Measurement and Clinical Significance of Biomarkers of Oxidative Stress in Humans

Oxidative stress is the result of the imbalance between reactive oxygen species (ROS) formation and enzymatic and nonenzymatic antioxidants. Biomarkers of oxidative stress are relevant in the evaluation of the disease status and of the health-enhancing effects of antioxidants. We aim to discuss the major methodological bias of methods used for the evaluation of oxidative stress in humans. There is a lack of consensus concerning the validation, standardization, and reproducibility of methods for the measurement of the following: (1) ROS in leukocytes and platelets by flow cytometry, (2) markers based on ROS-induced modifications of lipids, DNA, and proteins, (3) enzymatic players of redox status, and (4) total antioxidant capacity of human body fluids. It has been suggested that the bias of each method could be overcome by using indexes of oxidative stress that include more than one marker. However, the choice of the markers considered in the global index should be dictated by the aim of the study and its design, as well as by the clinical relevance in the selected subjects. In conclusion, the clinical significance of biomarkers of oxidative stress in humans must come from a critical analysis of the markers that should give an overall index of redox status in particular conditions.

Increased oxidative stress in pemphigus vulgaris is related to disease activity and HLA-association

Pemphigus vulgaris (PV) is a rare blistering skin disorder characterized by the disadhesion of keratinocytes due to autoantibody attack against epidermal targets including desmoglein (Dsg) 3, Dsg 1 and possibly other adhesion and non-adhesion molecules. The mechanisms leading to immune-mediated pathology in PV are multifactorial and not fully understood. Recently, oxidative stress (antioxidant/oxidant disequilibrium) has been proposed as a contributory mechanism of autoimmune skin diseases, including PV. In this study, we directly assessed oxidative stress via measurement of total antioxidant capacity (TAC) using ELISA in 47 PV patients, 25 healthy controls and 18 bullous pemphigoid (BP) patients. We also performed microarray gene expression analysis on a separate set of 21 PV patients and 10 healthy controls to evaluate transcriptional dysregulation in oxidative stress-related pathways. Our data indicate that there is a significant reduction in TAC levels in PV patients compared with healthy controls, as well as BP patients. Furthermore, PV patients with active disease have significantly lower TAC levels than PV patients in remission. We also find that HLA allele status has a significant influence on oxidative stress. These findings are corroborated by microarray analysis showing differentially expressed genes involved in oxidative stress between the aforementioned groups. Collectively, our findings provide support for a role of oxidative stress in PV. Whether increased oxidative stress leads to disease manifestation and/or activity, or if disease activity leads to increased oxidative stress remains unknown. Future longitudinal studies may help to further elucidate the relationship between PV and oxidative stress.

Salivary and Urinary Total Antioxidant Capacity as Biomarkers of Oxidative Stress in Humans

Total Antioxidant Capacity (TAC) is a biomarker often used in order to investigate oxidative stress in many pathological conditions. Saliva and urine can be collected noninvasively and represent attractive diagnostic fluids for detecting biomarkers of various pathological conditions. The reviewed case-control and intervention studies that measured salivary or urinary TAC revealed that diseases, antioxidant foods, or supplements and age, gender, and lifestyle factors influenced salivary or urinary TAC. Salivary and urinary TAC were particularly affected by oral or renal status, respectively, as well as by infection; therefore these factors must be taken into account in both case-control and intervention studies. Furthermore, some considerations on sample collection and normalization strategies could be made. In particular, unstimulated saliva could be the better approach to measure salivary TAC, whereas 24 h or spontaneous urine collection should be chosen on the basis of the study outcome and of the creatinine clearance. Finally, the uric acid-independent TAC could be the better approach to evaluate red-ox status of body, in particular after nutritional interventions and in diseases associated with hyperuricaemia.

Thiobarbituric acid reactive substances (TBARS) is a state biomarker of oxidative stress in bipolar patients in a manic phase

OBJECTIVES

Oxidative stress may contribute to the pathophysiology of bipolar disorder. The aim of this study was to investigate the serum levels or activities of oxidative stress markers in bipolar patients in a manic phase, and evaluate the changes in superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), thiobarbituric acid reactive substances (TBARS), protein carbonyl content (PCC) and 8-hydroxy 2'-deoxyguanosine after treatment (8-OHdG).

METHODS

We consecutively enrolled 23 bipolar inpatients in a manic phase and 40 healthy subjects. Serum oxidative stress markers were measured with assay kits. All patients were evaluated by examining the correlation between oxidative stress markers and Young Mania Rating Scale (YMRS) scores.

RESULTS

The serum TBARS levels in bipolar patients in a manic phase were significantly higher than those of healthy subjects (p=0.006), and serum GPx activity was significant lower than that of healthy subjects (p<0.05). The YMRS scores had a significantly positive association with CAT activity and PCC levels (p<0.05) and a negative association with GPx activity (p<0.05). Twenty bipolar patients were followed up, and their oxidative stress markers were measured at the end of treatment. We found significantly decreased changes in TBARS levels only in bipolar manic patients after treatment (p=0.019).

LIMITATION

Our sample size was limited.

CONCLUSION

Our results suggest that serum TBARS levels might be a state biomarker of oxidative stress in bipolar patients in a manic phase and after treatment. In addition, GPx deficit might be a trait biomarker of severity of mania.

Oxidative status in different settings and with different methodological approaches compared by Receiver Operating Characteristic curve analysis

OBJECTIVES

To test the performance of different analytical approaches in highlighting the occurrence of deregulated redox status in various physio-pathological situations.

DESIGN AND METHODS

35 light and 61 heavy smokers, 19 chronic renal failure, 59 kidney transplanted patients, and 87 healthy controls were retrospectively considered for the study. Serum oxidative stress and antioxidant status, assessed by spectrophotometric Reactive Oxygen Metabolites (d-ROMs) and Total Antioxidant Capacity (TAC) tests, respectively, were compared with plasma free (F-MDA) and total (T-MDA) malondialdehyde, both quantified by isotope-dilution-gas chromatography-mass spectrometry (ID-GC-MS). Sensitivity, specificity and cut-off points of T-MDA, F-MDA, d-ROMs and TAC were evaluated by both Receiver Operating Characteristic (ROC) analyses and area under the ROC curve (AUC).

RESULTS

Only T-MDA assay showed a clear absence of oxidative stress in controls and significant increase in all patients (AUC 1.00, sensitivity and specificity 100%). Accuracy was good for d-ROMs (AUC 0.87, sensitivity 72.8%, specificity 100%) and F-MDA (AUC 0.82, sensitivity 74.7%, specificity 83.9%), but not high enough for TAC to show in patients impaired antioxidant defense (AUC 0.66, sensitivity 52.0%, specificity 92.9%).

CONCLUSIONS

This study reveals T-MDA as the best marker to detect oxidative stress, shows the ability of d-ROMs to identify modified oxidative status particularly in the presence of high damages, and evidences the poor TAC performance. d-ROMs and TAC assays could be useful for routine purposes; however, for an accurate clinical data evaluation, their comparison versus a "gold standard method" is required.

The effect of sample storage on the Peroxidation of Leukocytes Index Ratio (PLIR) measure

Delays in processing are frequent because of problems associated with transporting the samples to the laboratory. Thus, we aimed to evaluate the effect of sample storage on the Peroxidation of Leukocytes Index Ratio (PLIR). Differences between PLIR values of lymphocytes (PLIR-L), monocytes (PLIR-M) and granulocytes (PLIR-G) were observed in fresh samples. Sample storage affected the evaluation of PLIR. In particular, PLIR-L was lower in stored samples compared to fresh samples. In conclusion, our results suggest that fresh samples are recommended for assessing the PLIR.

Nitric oxide synthetic pathway in patients with microvascular angina and its relations with oxidative stress

A decreased nitric oxide (NO) bioavailability and an increased oxidative stress play a pivotal role in different cardiovascular pathologies. As red blood cells (RBCs) participate in NO formation in the bloodstream, the aim of this study was to outline the metabolic profile of L-arginine (Arg)/NO pathway and of oxidative stress status in RBCs and in plasma of patients with microvascular angina (MVA), investigating similarities and differences with respect to coronary artery disease (CAD) patients or healthy controls (Ctrl). Analytes involved in Arg/NO pathway and the ratio of oxidized and reduced forms of glutathione were measured by LC-MS/MS. The arginase and the NO synthase (NOS) expression were evaluated by immunofluorescence staining. RBCs from MVA patients show increased levels of NO synthesis inhibitors, parallel to that found in plasma, and a reduction of NO synthase expression. When summary scores were computed, both patient groups were associated with a positive oxidative score and a negative NO score, with the CAD group located in a more extreme position with respect to Ctrl. This finding points out to an impairment of the capacity of RBCs to produce NO in a pathological condition characterized mostly by alterations at the microvascular bed with no significant coronary stenosis.

Contrast Layering

Patients with angiographically normal coronary arteries sometimes exhibit delayed clearance of contrast medium. This contrast layering (CL) was tested with intravascular ultrasound (IVUS) and markers of endothelial dysfunction and oxidative stress. The study group (n = 26) consisted of patients with CL and the control group (n = 32) comprised patients with normal coronary arteries despite angina symptoms. The CL was observed in 36 coronary arteries of 26 patients in the study group. Total antioxidant status and nitric oxide levels were significantly lower; total oxidant status, malondialdehyde plasma levels, and oxidative stress index were significantly higher in patients with CL than in controls. The IVUS studies revealed that atherosclerotic plaque burden, fibrous tissue, dense calcific tissue, and necrotic core ratios were significantly higher in the coronary segments with CL compared with adjacent normal segments. These results support the concept of CL as a new angiographic appearance of early atherosclerosis.

Circulating levels of linoleic acid and HDL-cholesterol are major determinants of 4-hydroxynonenal protein adducts in patients with heart failure

OBJECTIVE

Measurements of oxidative stress biomarkers in patients with heart failure (HF) have yielded controversial results. This study aimed at testing the hypothesis that circulating levels of the lipid peroxidation product 4-hydroxynonenal bound to thiol proteins (4HNE-P) are strongly associated with those of its potential precursors, namely n-6 polyunsaturated fatty acids (PUFA).

METHODS AND RESULTS

Circulating levels of 4HNE-P were evaluated by gas chromatography-mass spectrometry in 71 control subjects and 61 ambulatory symptomatic HF patients along with various other clinically- and biochemically-relevant parameters, including other oxidative stress markers, and total levels of fatty acids from all classes, which reflect both free and bound to cholesterol, phospholipids and triglycerides. All HF patients had severe systolic functional impairment despite receiving optimal evidence-based therapies. Compared to controls, HF patients displayed markedly lower circulating levels of HDL- and LDL-cholesterol, which are major PUFA carriers, as well as of PUFA of the n-6 series, specifically linoleic acid (LA; P=0.001). Circulating 4HNE-P in HF patients was similar to controls, albeit multiple regression analysis revealed that LA was the only factor that was significantly associated with circulating 4HNE-P in the entire population (R (2)=0.086; P=0.02). In HF patients only, 4HNE-P was even more strongly associated with LA (P=0.003) and HDL-cholesterol (p<0.0002). Our results demonstrate that 4HNE-P levels, expressed relative to HDL-cholesterol, increase as HDL-cholesterol plasma levels decrease in the HF group only.

CONCLUSION

Results from this study emphasize the importance of considering changes in lipids and lipoproteins in the interpretation of measurements of lipid peroxidation products. Further studies appear warranted to explore the possibility that HDL-cholesterol particles may be a carrier of 4HNE adducts.

A plasma oxidative stress global index in early stages of chronic venous insufficiency

BACKGROUND

Chronic venous insufficiency (CVI) represents a social and health care problem because it affects working age populations, particularly in jobs requiring orthostasis, has no effective pharmacologic treatment, and requires surgery. Oxidative stress is present in varicose veins, but whether this is reflected in the plasma is controversial. We aimed to quantify plasma oxidative stress biomarkers in the early stages of CVI and calculate a global index of oxidative stress representative of the disease.

METHODS

Plasma was obtained from blood samples of nine patients with CEAP C2 stage CVI and 10 healthy controls. Biomarkers related to antioxidant defense systems (total thiols, reduced glutathione, uric acid, total antioxidant capacity, catalase), oxidative damage (malondialdehyde-bound protein, protein carbonyls, advanced oxidation products, and 3-nitrotyrosine), and activity of enzymes producing key free radicals (xanthine oxidase and myeloperoxidase) were assessed.

RESULTS

Compared with the controls, CVI patients exhibited decreased catalase activity and thiol levels and increased malondialdehyde-bound protein and protein carbonyls. These parameters were used to calculate the global index of oxidative stress in CVI, which was significantly different between groups.

CONCLUSIONS

It is possible to detect significant changes in plasma oxidative stress biomarkers in early stages of CVI and to calculate a global index representative of the oxidative status in an individual. This index, with the appropriate validation in a larger population, could be used for early detection or progression of CVI.

Direct glutathione quantification in human blood by LC-MS/MS: comparison with HPLC with electrochemical detection

Glutathione plays a central role in the defence against oxidative damage and in signaling pathways. Upon oxidation the reduced glutathione (GSH) is transformed to glutathione disulfide (GSSG). The concentration of GSH and GSSG in whole blood samples and their ratios is useful indicator of the oxidative stress status and/or disease risk. Here we describe a liquid-chromatographic method coupled with tandem mass spectrometry (LC-MS/MS) and we present the results of its comparison with a high-performance liquid-chromatographic method with electrochemical detection (HPLC-ECD). The method performed well in terms of validation parameters, i.e. linear range (0.01-50μM for both GSH and GSSG), precision (intra- and inter-day coefficients of variation were less than 10% for both GSH and GSSG), accuracy (bias% varied between -2.1 and 7.9% for both analytes), quantification limits (LLOQs were 0.5μM and 0.0625μM for GSH and GSSG respectively). Furthermore the LC-MS/MS method showed a good agreement with the HPLC-ECD assay. However, major benefits of LC-MS/MS are the improved selectivity, precision and accuracy, the higher sensitivity and the unaltered capacity of detection with time in contrast to ECD.

Determinants of oxidative stress related to gender: relevance of age and smoking habit

BACKGROUND

Magnitude and major causes of oxidative stress may be different between sexes, although limitedly addressed in clinical studies with controversial results. The present study aimed to determine whether any gender-related difference exists concerning oxidative stress in a population of 332 subjects of both sexes, in a wide age range, with and without cigarette smoking habit.

METHODS

The Oxidative-INDEX was calculated after evaluation of serum hydroperoxides (ROMs) and total antioxidant capacity (OXY) by means of commercial kits (d-ROMs and Oxy-adsorbent Tests, Diacron, Italy) subtracting the OXY standardized variable from the ROMs standardized variable.

RESULTS

The Oxidative-INDEX resulted higher in women with respect to men (p<0.001), in smokers (p<0.01) than in non-smokers, and correlated with cigarette number (p<0.01), age (p<0.001), and post-menopausal status (p<0.001). The multivariate analysis identified age, high blood pressure, and smoking habit as factors independently associated with the Oxidative-INDEX in men, whereas cigarette smoking and age represented the independent risk factors for an elevated oxidative stress status in women.

CONCLUSIONS

Gender-based differences in oxidative stress levels may provide a biochemical basis for the epidemiologic differences in the disease susceptibility between sexes, and suggest different strategies for risk assessment, diagnosis, and treatment specifically targeted to men and women.

Lifestyle Behaviours and Plasma Vitamin C and β-Carotene Levels from the ELAN Population (Liège, Belgium)

Several factors, including fruit and vegetables intakes, have been shown to significantly influence the plasma concentrations of the two antioxidants vitamin C and β-carotene. Deficiency levels of 6 mg/L (34.2 μM) for vitamin C and of 0.22 mg/L (0.4 μM) for β-carotene have been suggested below which cardiovascular risk might be increased. The present study performed on 897 presumably healthy subjects aged 40–60 years aimed to examine how modifiable lifestyle factors may be related to vitamin C and/or β-carotene deficiency. Gender, smoking, lack of regular physical activity and of daily fruit consumption (≥2/day), and social status (in particular, unemployment) were found to be significant risk factors for vitamin C deficiency. For β-carotene deficiency, the same factors were identified except social status; moreover, overweight and OC use in women were also found to have a deleterious effect. For non exposed subjects, the probability of developing vitamin C deficiency was 4% in men and 2.4% in women. This probability increased to 66.3% for men and to 44.3% for women (and even to 50.4% under OC use), when all risk factors were present. For β-carotene deficiency, the corresponding probabilities were equal to 29.7% in men and 13.7% in women (no risk factor present), and to 86.1% for men and 69.9% (91.6% for OC use) for women (all factors present), respectively.

Reduced cerebral blood flow in older men with higher levels of blood pressure

OBJECTIVE

To examine relations of blood pressure (BP) with single photon emission computed tomography (SPECT)-derived estimates of cerebral blood flow in older men and women.

METHODS

Seventy-four stroke and dementia-free, community-dwelling older adults (ages 54-83 years; 68% men; 91% white) free of major medical, neurological, or psychiatric disease, engaged in clinical assessment of resting SBP and DBP, MRI rated for brain atrophy, and brain single photon emission computed tomography (SPECT) studies with computerized coding of cortical and select subcortical regions of interest.

RESULTS

Given significant interactions of BP and sex with respect to multiple SPECT outcomes, sex-stratified multiple regression models were computed. Models were adjusted for age, fasting glucose levels, antihypertensive medication, BMI, and MRI ratings of brain atrophy. In men (n = 50), higher levels of SBP and/or DBP were associated significantly with lower estimates of cerebral perfusion in the right and left frontal, temporal, parietal, and occipital cortex, thalamus, head of caudate, and cingulate cortex accounting for up to 28% of the variance in these measures (P < 0.05). In women (n = 24), higher DBP was related marginally to higher levels of perfusion in the right temporal cortex (P = 0.05).

CONCLUSION

Higher resting SBP or DBP was associated with lower levels of cerebral perfusion in otherwise healthy older men, but not women, in the present sample. Reduced cerebral blood flow may play a pathogenic role in increasing risk for stroke, dementia, and/or cognitive decline, particularly among older men with high BP.

Myeloperoxidase and C-reactive protein have combined utility for long-term prediction of cardiovascular mortality after coronary angiography

OBJECTIVES

We evaluated the relative and combined value of oxidative stress biomarkers for predicting cardiovascular mortality in patients undergoing selective coronary angiography.

BACKGROUND

Oxidative stress participates in all stages of cardiovascular disease, from lipoprotein modification to plaque rupture, and biomarkers of oxidative stress predict development of coronary artery disease (CAD). Oxidative stress biomarkers merit investigation for the value they may offer for long-term cardiovascular risk prediction.

METHODS

Myeloperoxidase (MPO), nitrotyrosine, oxidized low-density lipoprotein, and antioxidant capacity were measured in a prospective cohort of 885 selective coronary angiography patients followed up for >13 years for cardiovascular mortality.

RESULTS

MPO independently predicted CAD, and top tertile MPO levels predicted a 2.4-fold risk of cardiovascular mortality (95% confidence interval [CI]: 1.47 to 2.98), compared with patients with lowest tertile MPO levels. MPO also improved risk model discrimination and patient risk category classification. Elevations in multiple oxidative stress biomarkers predicted increased mortality risk; however, the strongest risk prediction was achieved by assessing MPO and C-reactive protein (CRP) together. Patients with either MPO or CRP elevated had 5.3-fold higher cardiovascular mortality risk (95% CI: 1.86 to 14.9), and patients with high levels of both MPO and CRP had a 4.3-fold risk compared with patients with only elevated marker (95% CI: 2.26 to 8.31). These results remained significant with adjustment for cardiovascular risk factors and baseline disease burden.

CONCLUSIONS

MPO accurately predicted cardiovascular mortality risk in coronary angiography patients. Considering MPO and CRP together may improve long-term risk assessment and CAD patient outcomes.

Assessment of oxidative stress in coronary artery bypass surgery: comparison between the global index OXY-SCORE and individual biomarkers

The performances of the OXY-SCORE, a summary index of oxidative stress, and of its individual components (plasma malondialdehyde (MDA), oxidized and reduced glutathione, individual antioxidant capacity, alpha- and gamma-tocopherol and urinary isoprostanes) were assessed in 47 patients undergoing coronary surgery, randomly assigned to cardiopulmonary bypass (CPB) or off-pump procedure (OPCAB) associated with less oxidative stress. The ability of the OXY-SCORE to classify correctly the patients was high (area under the ROC curve 0.90). Only free MDA showed a similar performance, but it was insensitive to the minor variations of the oxidative balance in the OPCAB group.

OXY-SCORE: a global index to improve evaluation of oxidative stress by combining pro- and antioxidant markers

Our group recently proposed OXY-SCORE, a summary index of oxidative stress, computed by combining plasma free and total malondialdehyde (F- and T-MDA), glutathione in disulphide/reduced forms (GSSG/GSH), alpha- and gamma-tocopherol (TH), urine isoprostanes (iPF(2alpha)-III) levels, and plasma individual antioxidant capacity. Here, we describe the methods for the determination of the analytes and for the computation of the scores. We also report the results of two studies testing the performances of OXY-SCORE, and showing its value in assessing the oxidative status of cardiovascular patients and healthy subjects.

Glutathione, vitamin E and oxidative stress in coronary artery disease: relevance of age and gender

BACKGROUND

Observational studies suggest that low levels of antioxidants are associated with high risk for coronary artery disease (CAD). We investigated whether the biomarkers of oxidative balance undergo the same modifications in all CAD patient groups, regardless of gender and age.

MATERIALS AND METHODS

One hundred sixty-eight CAD patients and 107 healthy controls were assayed for plasma levels of reduced glutathione (GSH), alpha- and gamma-tocopherol (alpha- and gamma-T) as endogenous antioxidants. A damage score (DS), representative of oxidative stress status, was calculated. ANCOVA models were used to test the association between antioxidants, DS and CAD and its modulation by age and gender.

RESULTS

The DS was higher in CAD than in controls. GSH levels, were lower in CAD patients (mean +/- SEM: 57.61 +/- 1.87 micromol 10 g(-1) haemoglobin vs. 68.55 +/- 2.23 in controls, P < 0.0006) in males and in older subjects. Levels of other antioxidants exhibited a complex pattern. Overall, no difference was found in alpha- and gamma-T contents between CAD and controls, but lower alpha-T values were observed in CAD females. A significant interaction between CAD status and gender was observed (P = 0.003).

CONCLUSIONS

Our study shows that the involvement of antioxidants in CAD is related to patients' characteristics. These findings may be relevant in planning antioxidant therapies.

Glucose fluctuations and activation of oxidative stress in patients with type 1 diabetes

AIMS/HYPOTHESIS

Glucose fluctuations may help predict diabetic complications. We evaluated the relation between glucose variability and oxidative stress in patients with type 1 diabetes.

METHODS

Continuous glucose monitors were inserted subcutaneously in 25 patients. During the measurement, patients collected two 24 h urine samples, while 24 healthy controls collected one 24 h urine sample for determination of 15(S)-8-iso-prostaglandin F2alpha(PGF2alpha) using HPLC tandem mass spectrometry. Mean of the daily differences (MODD), mean amplitude of glycaemic excursions (MAGE) and continuous overlapping net glycaemic action calculated with n hour time-intervals (CONGA-n) were calculated as markers for glucose variability and correlation with 15(S)-8-iso-PGF2alpha excretion was calculated.

RESULTS

Median [interquartile range (IQR)] urinary 15(S)-8-iso-PGF2alpha was higher in patients than healthy controls: 161 (140-217) pg/mg creatinine vs 118 (101-146) pg/mg creatinine (p = 0.001). Median (IQR) MODD was 3.7 (3.2-5.0) mmol/l, MAGE 7.6 (6.4-9.0) mmol/l and CONGA-1 2.3 (2.1-2.8) mmol/l. Univariate regression did not reveal an association for MODD (r2 = 0.01), MAGE (0.08) or CONGA-1 (0.07) with 15(S)-8-iso-PGF2alpha excretion, nor was an association revealed when corrected for HbA1c, age, sex and smoking. Spearman correlation coefficients (r) between 15(S)-8-iso-PGF2alpha excretion and MODD, MAGE and CONGA-1 were non-significant: -0.112, -0.381 and -0.177.

CONCLUSIONS/INTERPRETATION

We report that there is no relationship between glucose variability and urinary 15(S)-8-iso-PGF2alpha. We also confirm that patients with type 1 diabetes have higher levels of urinary 15(S)-8-iso-PGF2alpha than healthy controls, suggesting that in addition to glucose variability, other factors favouring oxidative stress may exist. We did not see a relation between high glucose variability and elevated levels of oxidative stress in patients with type 1 diabetes.