New Marker Of Oxidative Stress Research Articles

Adduct of Malondialdehyde to Hemoglobin: A New Marker of Oxidative Stress That Is Associated with Significant Morbidity in Preterm Infants

Preterm infants (PT) are particularly exposed to oxidative stress (OS), and a blood-sparing marker, the malondialdehyde adduct to hemoglobin (MDA-Hb), may be useful to accurately assess OS-related neonatal morbidity. In a prospective study, MDA-Hb concentrations were assessed in two groups of PT, one with and one without severe neonatal morbidity as estimated by a composite index of severe morbidity (ISM). All PT born in a single tertiary care NICU (<32 weeks and birth weight <1500 g) were consecutively included. MDA-Hb and blood glutathione (GSH) concentrations were measured by liquid chromatography-mass spectrometry during the first 6 weeks of life. Linear regressions and a multilevel model were fitted to study the relationship between MDA-Hb or GSH and ISM. Of the 83 PT (mean ± SD: 28.3 ± 2 weeks, 1089 ± 288 g), 21% presented severe neonatal morbidity. In the multivariate model, MDA-Hb concentrations were significantly higher in the ISM+ group than in the ISM– group during the first 6 weeks of life (P = 0.009). No significant difference in GSH concentrations was observed between groups (P = 0.180). MDA-Hb is a marker of interest for estimating oxidative stress in PT and could be useful to evaluate the impact of strategies to improve perinatal outcomes.

Ischemia modified albumin: An oxidative stress marker in β-thalassemia major

BackgroundIschemia modified albumin (IMA) is an altered type of serum albumin that forms under conditions of oxidative stress. This study reports on the levels and clinical significance of IMA in patients with β-thalassemia major. MethodsBlood specimens were collected from 166 subjects (101 β-thalassemia major patients and 65 healthy controls). Serum levels of IMA, ferritin, malondialdehyde (MDA), ferroxidase, transaminases, total protein, and albumin were determined using conventional methods. ResultsSerum levels of IMA (ABSU) were significantly higher in patients than in controls (0.725±0.155 vs 0.554±0.154, p=0.000). Similarly, higher levels were also observed for ferritin, MDA, ferroxidase, and transaminases. No significant differences were observed between patients and controls with respect to total protein and albumin. Spearman univariate analysis demonstrated significant correlation between IMA and ferritin, MDA, ferroxidase, and transaminases. Multiple linear regression analysis revealed significant association of IMA with ferritin and ferroxidase after adjusting for the other variables (r=0.343, p=0.002; r=0.228, p=0.029 respectively). MDA however, correlated significantly with ferritin only (r=0.654, p=0.000). ConclusionOur findings suggest that increased levels of IMA in thalassemic patients are likely to be a result of iron-induced oxidative stress and hence its potential significance as a new marker of oxidative stress in such patients.

Exhaled breath 8-isoprostane as a marker of asthma severity.

IntroductionOxidative stress is a non-specific feature of airway inflammation in asthmatics. 8-Isoprostane (8-IP), a prostaglandin-F2α isomer, is a relatively new marker of oxidative stress and may be measured in exhaled breath condensate (EBC) of patients with asthma. This research study aimed to evaluate the usefulness of EBC 8-IP as a marker of severity and control of severe adult asthma.Material and methodsTwenty-seven severe, never-smoking asthmatics were studied. According to positive or negative reversibility testing, this group was subdivided into reversible and irreversible asthma groups. All participants were observed for 8 weeks during which they completed daily diary observations including day and night symptoms, number of awakenings, peak expiratory flow (PEF) variability, daily rescue medication usage and oral steroids consumption. They attended the clinic 3 times and on these occasions spirometry assessments, EBC collection and asthma control tests (ACT) were done. Two control groups were included: 11 healthy never-smokers and 16 newly diagnosed and never-treated, non-smoking mild asthmatics.ResultsThere were no statistically significant differences between severe asthma and healthy control or never-treated asthma groups in concentrations of EBC 8-IP (median and interquartile range: 4.67; 2.50-27.92 vs. 6.93; 2.5-12.98 vs. 3.80; 2.50-10.73, respectively). No correlations were found between EBC 8-IP and asthma control parameters, such as ACT results, night and day symptoms, consumption of rescue medication, percentage of days free of oral steroids, PEF diurnal variation, lung function test results, forced expiratory volume in the 1 s reversibility, and markers of systemic inflammation.ConclusionsOur study results suggest that EBC 8-IP measurements are not useful for asthma monitoring.

Biochemical Measurement of Neonatal Hypoxia

Neonatal hypoxia ischemia is characterized by inadequate blood perfusion of a tissue or a systemic lack of oxygen. This condition is thought to cause/exacerbate well documented neonatal disorders including neurological impairment. Decreased adenosine triphosphate production occurs due to a lack of oxidative phosphorylation. To compensate for this energy deprived state molecules containing high energy phosphate bonds are degraded. This leads to increased levels of adenosine which is subsequently degraded to inosine, hypoxanthine, xanthine, and finally to uric acid. The final two steps in this degradation process are performed by xanthine oxidoreductase. This enzyme exists in the form of xanthine dehydrogenase under normoxic conditions but is converted to xanthine oxidase (XO) under hypoxia-reperfusion circumstances. Unlike xanthine dehydrogenase, XO generates hydrogen peroxide as a byproduct of purine degradation. This hydrogen peroxide in combination with other reactive oxygen species (ROS) produced during hypoxia, oxidizes uric acid to form allantoin and reacts with lipid membranes to generate malondialdehyde (MDA). Most mammals, humans exempted, possess the enzyme uricase, which converts uric acid to allantoin. In humans, however, allantoin can only be formed by ROS-mediated oxidation of uric acid. Because of this, allantoin is considered to be a marker of oxidative stress in humans, but not in the mammals that have uricase. We describe methods employing high pressure liquid chromatography (HPLC) and gas chromatography mass spectrometry (GCMS) to measure biochemical markers of neonatal hypoxia ischemia. Human blood is used for most tests. Animal blood may also be used while recognizing the potential for uricase-generated allantoin. Purine metabolites were linked to hypoxia as early as 1963 and the reliability of hypoxanthine, xanthine, and uric acid as biochemical indicators of neonatal hypoxia was validated by several investigators. The HPLC method used for the quantification of purine compounds is fast, reliable, and reproducible. The GC/MS method used for the quantification of allantoin, a relatively new marker of oxidative stress, was adapted from Gruber et al. This method avoids certain artifacts and requires low volumes of sample. Methods used for synthesis of MMDA were described elsewhere. GC/MS based quantification of MDA was adapted from Paroni et al. and Cighetti et al. Xanthine oxidase activity was measured by HPLC by quantifying the conversion of pterin to isoxanthopterin. This approach proved to be sufficiently sensitive and reproducible.

Ischemia-modified albumin and cardiovascular risk markers in polycystic ovary syndrome with or without insulin resistance

The aim of this study was to evaluate ischemia-modified albumin levels (IMA) in polycystic ovary syndrome (PCOS) cases with and without insulin resistance and the correlation of IMA with carotid intima media thickness, homocysteine, and high-sensitivity C-reactive protein levels. Significantly higher levels of IMA in young lean PCOS cases, more relevant in insulin resistant cases, indicates chronic hypoxia and oxidative stress which might play a role in the metabolic consequences in PCOS.

Increased Serum Levels of Nɛ-(hexanoyl)lysine, A New Marker of Oxidative Stress, in Systemic Sclerosis

To determine serum levels of N(epsilon)-(hexanoyl)lysine (HEL), a new marker of oxidative stress, and its clinical association in patients with systemic sclerosis (SSc). Serum HEL levels from 26 patients with limited cutaneous SSc (lSSc), 34 with diffuse cutaneous SSc (dSSc), 20 with systemic lupus erythematosus (SLE), 20 with dermatomyositis (DM), and 40 healthy individuals were examined by enzyme linked immunosorbent assay. Serum HEL levels were elevated in patients with SSc compared with healthy controls (n = 40) with similar levels between patients with lSSc and dSSc (p < 0.0001). SSc patients with elevated HEL levels had increased serum levels of anti-agalactosyl IgG antibody, rheumatoid factor (RF), and IgM than those with normal HEL levels (p < 0.05). HEL levels correlated positively with anti-agalactosyl IgG antibody (p = 0.013, r = 0.408) and RF titer (p = 0.0028, r = 0.426). Our results suggest that oxidative stress may play an important role in immunological abnormalities of SSc, especially in the production of autoantibodies including anti-agalactosyl IgG antibody and RF.

Evaluation of allantoin levels as a new marker of oxidative stress in Behçet's disease

The increased production of reactive oxygen species (ROS) from activated neutrophils in Behçet's disease (BD) and recurrent aphthous stomatitis (RAS) may result in increased oxidative stress. Uric acid can react rapidly with neutrophil‐derived ROS to form allantoin. The purpose of the study was to evaluate the serum levels of allantoin as a new marker of oxidative stress in BD compared with malondialdehyde (MDA) levels as a well‐known marker. Blood samples were obtained from 23 BD patients, 22 RAS patients as positive controls, and 21 healthy controls. When compared to the healthy controls, we found higher allantoin and MDA levels in the BD patients and higher MDA levels in the RAS patients. Serum ascorbic acid levels in the BD patients were significantly lower than in the controls. Increased allantoin and MDA levels suggest the possible involvement of free radicals in BD. As allantoin is only a product of uric acid oxidation by reactive oxygen and nitrogen species, it may also be used as a marker of oxidative stress in BD.

Les biomarqueurs de la peroxydation lipidique

Different biomarkers related to lipid peroxidation are available to assess an oxidative stress. They are more or less specific and sensitive. For instance malondialdehyde (MDA) or conjugated diene are easily measured in different matrix. Their measurements provide only a rough indication assessing an oxidative stress. But sometimes information is wrong due to artefacts. Some markers such as isoprostanes are specific of arachidonic acid only, and they require expensive equipment such as GC-MS/MS. They are mainly dedicated to clinical investigation. We present here new markers of oxidative stress which allow to discriminate between the oxidation of polyunsaturated fatty acid families. They are 4-hydroxynonenal (4-HNE) and 4-hydroxy-hexenal (4-HHE) which represent the peroxidation of the n-6 and n-3 polyunsaturated fatty acids, respectively and 4-hydroxy-dodecadienal (4-HDDE) which derives from the breakdown of 12-HpETE and mainly reflects the 12 lipoxygenation of arachidonic acid. Those markers can be easily measured with a high sensitivity by GC-MS in plasma. Their urinary carboxylic oxidized end-products, namely 4-HNA, 4-HHA and 4-HDDA may also be measured by GC-MS. The choice between these different biomarkers is not easy. It depends on which information is required.

Plasma phosphatidylcholine hydroperoxide as a new marker of oxidative stress in alcoholic patients

Quantitative analysis of plasma phosphatidylcholine hydroperoxide (PCOOH) is an important step in evaluating the biochemical processes leading to oxidative injury. However, secondary products of lipid peroxidation are now used as indices. One hundred nine alcoholic patients, aged 22-81 years (mean +/- SEM, 52.0 +/- 1.3 years), and 21 healthy volunteers, aged 41-79 years (51.2 +/- 2.2 years), participated in this study. Plasma PCOOH was measured by HPLC with chemiluminescence detection. Plasma PCOOH concentration was significantly higher in alcoholic patients (46.1 +/- 4.1 pmol/ml) than in controls (15.6 +/- 1.8 pmol/ml). It was significantly higher in patients with blood alcohol (88.0 +/- 10.5 pmol/ml) than in those without alcohol (32.6 +/- 3.1 pmol/ml). The patients with high levels of aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transpeptidase (gamma-GTP), and triglyceride (TG) showed significantly higher PCOOH concentrations than did patients with normal levels. The PCOOH level was positively correlated with levels of gamma-GTP, HDL, blood alcohol concentration, and TG. Plasma PCOOH levels in 29 alcoholic patients after a 6 week abstinence were decreased significantly (22.8 +/- 11.1 pmol/ml), which was associated with improvement on liver function tests. This is the first measurement of plasma PCOOH in alcoholic patients. These results suggest the involvement of lipid peroxidation in alcohol-induced liver damage and confirm that the PCOOH plasma concentration is a new marker of alcohol consumption as well as oxidative stress in alcoholic patients.

Are advanced oxidation protein products potential uremic toxins?

Oxidative stress, defined as a disruption of the equilibrium between the generation of oxidants and the activity of anti-oxidant systems, plays a significant role in the development of the inflammatory syndrome associated with chronic renal failure and hemodialysis. In our recent work, the aim of which was to better characterize oxidative stress in dialysis patients, we described the presence of oxidized protein products, which we have termed advanced oxidation protein products (AOPP), in the plasma of dialysis patients and we proposed AOPP as new markers of oxidative stress and potential inflammatory mediators. AOPP represent an exquisite marker of phagocyte-derived oxidative stress, and their role in the pathophysiology of chronic renal failure and dialysis-related complications might be of great importance. Regarding the mechanisms of generation of AOPP, we pointed out the importance of myeloperoxidase and the subsequent generation of chlorinated oxidants, previously considered solely as microbicidal agents, in the formation of AOPP. Indeed, AOPP appear to act as true inflammatory mediators since they are able to trigger the oxidative burst and the synthesis of inflammatory cytokines in neutrophils, as well as in monocytes. Thus, it could be hypothesized that the AOPP, which arise from the reaction between chlorinated oxidants and plasma proteins, constitute new uremic toxins with pro-inflammatory effects.

Thioredoxin: a new marker of oxidative stress in patients with chronic heart failure

Thioredoxin: a new marker of oxidative stress in patients with chronic heart failure

Phytoestrogens attenuate oxidative DNA damage in vascular smooth muscle cells from stroke-prone spontaneously hypertensive rats.

A recent study demonstrated that reactive oxygen species (ROS) were involved in the maintenance of hypertension in stroke-prone spontaneously hypertensive rats (SHRSP). However, the role of oxidative stress in hypertension and its related diseases in SHRSP remains unknown. To determine whether phytoestrogens attenuate oxidative DNA damage in vascular smooth muscle cells (VSMC) from SHRSP and Wistar-Kyoto (WKY) rats, we investigated the effect of daidzein, genistein and resveratrol on oxidative DNA damage in VSMC, induced by advanced glycation end-products (AGEs). VSMC were treated with AGEs in the presence or absence of phytoestrogens for the indicated time. Cellular degeneration induced by AGEs was characterized in terms of intracellular oxidant levels, intracellular total glutathione (GSH) levels, mRNA expression for gamma-glutamylcysteine synthetase (GCS), and a new marker of oxidative stress, 8-hydroxy-2'-deoxyguanosine (8-OHdG) contents. AGEs stimulated 8-OHdG formation in VSMC in a time- and dose-dependent manner. We also confirmed that VSMC from SHRSP were more vulnerable to oxidative stress induced by AGEs, than VSMC from WKY rats. Daidzein, genistein or resveratrol reduced AGEs-induced 8-OHdG formation in a dose-dependent manner. The preventive effects of phytoestrogens on 8-OHdG formation remarkably paralleled changes in the intracellular oxidant levels in VSMC following AGEs treatment. We further demonstrated that phytoestrogens increase intracellular total GSH level in VSMC. Increased GSH synthesis was due to enhanced expression of the rate-limiting enzyme for GSH synthesis, GCS. Phytoestrogens-stimulated total GSH level in VSMC could lead to decreased intracellular oxidant levels, and thus prevent oxidative DNA damage, induced by AGEs. The phytoestrogens are powerful antioxidants able to interfere with AGEs-mediated oxidative DNA damage of VSMC, and are potentially useful against vascular diseases where ROS are involved in hypertension.

Effect of age on the breath methylated alkane contour, a display of apparent new markers of oxidative stress

Reactive oxygen species (ROS) are toxic byproducts of mitochondrial energy production that inflict oxidative stress, a constant barrage of damage to DNA, proteins, lipids, and other biologically important molecules. Oxidative stress has been implicated as a pathologic mechanism in aging and in several diseases. We developed a display of apparent new markers of oxidative stress in human beings, the breath methylated alkane contour (BMAC). The BMAC is a three-dimensional display of C4 to C20 alkanes and monomethylated alkanes in breath, with x-axis = carbon chain length, z-axis = methylation site, and y-axis = alveolar gradient (relative abundance in breath minus relative abundance in room air). In 102 normal human subjects of 9 to 89 years of age, alveolar gradients of components of the BMAC increased significantly with age. The mean alveolar gradient of all components of the BMAC varied from negative in the youngest quartile (ages 9 to 31 years) to positive in the oldest quartile (ages 74 to 89 years)(P < 2.10–9). These findings were consistent with an increase in oxidative stress with advancing age, although an age-related decline in clearance by cytochrome p450 may have contributed. The BMAC provides a display of apparent new markers of oxidative stress with potential applications in aging research, clinical diagnosis, pharmacology, and toxicology. (J Lab Clin Med 2000;136:243-9)

Effect of age on the profile of alkanes in normal human breath

Ethane and pentane in breath are markers of oxidative stress, produced by ROS-mediated lipid peroxidation of n-3 and n-6 polyunsaturated fatty acids (PUFAs), but little is known about other n-alkanes in normal human breath. We investigated the spectrum of alkanes in normal human alveolar breath, and their variation with age. Fifty normal humans were studied (age range 23–75, median 35). Volatile organic compounds (VOCs) in alveolar breath were captured on sorbent traps and assayed by gas chromatography and mass spectroscopy. Alveolar gradients (concentration in breath minus concentration in ambient room air) of alkanes were determined. C4–C20 alkanes were observed in breath and room air. Their mean alveolar gradients were negative from C4 to C12 and positive from C13 to C20. The mean alveolar gradients of four alkanes (C5–C8) were significantly less negative in the older subjects (p < 0.05). There were no significant differences between males and females. Normal human breath contained a spectrum of alkanes which may include new markers of oxidative stress. The mean rate of clearance (via cytochrome p450) exceeded the mean rate of synthesis (by ROS-mediated oxidative stress) for C4–C12 alkanes, while synthesis was greater than clearance for C13–C20 alkanes. The elevated alkane profile in older subjects was consistent with an age-related increase in oxidative stress, though an age-related decline in alkane clearance rate may have contributed.

Characterization of LY231617 protection against hydrogen peroxide toxicity.

The compound LY231617 [2,6-bis(1,1-dimethylethyl)-4-[[(1-ethyl)amino]methyl]phenol hydrochloride] has been reported to afford significant neuroprotection against hydrogen peroxide (H2O2)-induced toxicity in vitro and global ischemia in vivo. We now report on further mechanistic studies of H2O2 toxicity and protection by LY231617. Brief exposure to H2O2 (15 min) elicited an oxidative insult comparable with that generated by overnight treatment. H2O2-mediated cellular degeneration was characterized using lactate dehydrogenase (LDH) release, changes in total glutathione, and a new marker of oxidative stress, 8-epiprostaglandin F2alpha (8-isoprostane). LY231617 attenuated H2O2-mediated degeneration under a variety of exposure conditions, including a more clinically relevant posttreatment paradigm. Levels of 8-isoprostane paralleled LDH release under various treatment paradigms of 100 microM H2O2 +/- 5 microM drug. In contrast, despite affording significant protection, LY231617 had modest to no effects on cellular levels of glutathione. Taken together, these results are consistent with a membrane site of action for LY231617 and suggest that the compound affords cytoprotection via its antioxidant properties.

Increased levels of exhaled carbon monoxide in bronchiectasis: a new marker of oxidative stress

BACKGROUNDBronchiectasis is a chronic inflammatory lung disease associated with increased production of oxidants due mostly to neutrophilic inflammation. Induction of heme oxygenase (HO-1) by reactive oxygen species is a general...

Raised levels of exhaled carbon monoxide are associated with an increased expression of heme oxygenase-1 in airway macrophages in asthma: a new marker of oxidative stress

BACKGROUNDChronic inflammatory diseases are associated with an increased production of oxidants. Induction of a stress protein, heme oxygenase (HO) HO-1, is a cytoprotective mechanism against oxidative cellular injury. HO-1 catabolises...