Isoprostanes: novel bioactive products of lipid peroxidation

Phospholipids, Sphingolipids, and Cholesterol-Derived Lipid Mediators and Their Role in Neurological Disorders

Neural membranes are composed of phospholipids, sphingolipids, cholesterol, and proteins. In response to cell stimulation or injury, the metabolism of lipids generates various lipid mediators, which perform many cellular functions. Thus, phospholipids release arachidonic acid or docosahexaenoic acid from the sn-2 position of the glycerol moiety by the action of phospholipases A2. Arachidonic acid is a precursor for prostaglandins, leukotrienes, thromboxane, and lipoxins. Among these mediators, prostaglandins, leukotrienes, and thromboxane produce neuroinflammation. In contrast, lipoxins produce anti-inflammatory and pro-resolving effects. Prostaglandins, leukotrienes, and thromboxane are also involved in cell proliferation, differentiation, blood clotting, and blood vessel permeability. In contrast, DHA-derived lipid mediators are called specialized pro-resolving lipid metabolites (SPMs). They include resolvins, protectins, and maresins. These mediators regulate immune function by producing anti-inflammatory, pro-resolving, and cell protective effects. Sphingolipid-derived metabolites are ceramide, ceramide1-phosphate, sphingosine, and sphingosine 1 phosphate. They regulate many cellular processes, including enzyme activities, cell migration and adhesion, inflammation, and immunity. Cholesterol is metabolized into hydroxycholesterols and 7-ketocholesterol, which not only disrupts membrane fluidity, but also promotes inflammation, oxidative stress, and apoptosis. These processes lead to cellular damage.

Association between Serum 8-Iso-Prostaglandin F2α as an Oxidative Stress Marker and Immunological Markers in a Cohort of Preeclampsia Patients

BACKGROUND

We aimed to analyze the presence and clinical use of serum 8-iso-prostaglandin F2-alpha (8-iso-PGF2α) as an oxidative stress marker and some inflammatory status biomarkers (tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), IL-10, high-sensitivity C-reactive protein (hs-CRP), and pentraxin-3 (PTX3)) for patients with preeclampsia (PE).

METHODS

Sixty pregnant women, including thirty diagnosed with PE and thirty who were healthy (NP), were included in this study. For the assessment of serum levels of biomarkers, we used the Enzyme-Linked Immunosorbent Assay (ELISA) technique.

RESULTS

Our preliminary study showed that the expression level of serum 8-iso-PGF2α in the PE group was higher than in the PE after delivery (PE-AD) group (742.00 vs. 324.00 pg/mL, p < 0.0001). Groups of preeclamptic patients (PE + PE-AD) expressed significantly elevated levels for all of the assessed inflammatory mediators as compared to NP. Significant strong positive correlations with 8-iso-PGF2α levels were found for systolic blood pressure (SBP), and TNF-α (Spearman's rho = 0.622, p-value = 0.020 and rho = 0.645, p-value = 0.002, respectively). Our study demonstrates that 8-iso-PGF2α and PTX3 have the greatest diagnostic value for pregnant women with PE.

CONCLUSIONS

8-iso-PGF2α and PTX3 can be used as independent predictor factors, along with already-known cytokines, that could represent a prophylactic way to help clinicians identify or predict which pregnant women will develop PE.

The Relationship of Preconception and Early Pregnancy Isoprostanes with Fecundability and Pregnancy Loss

BACKGROUND

Although redox stress likely plays an important role in reproductive health, the utility of peripheral biomarkers of oxidative stress, such as isoprostanes, during the periconception period remains underexplored. We evaluated the relationship between isoprostanes during preconception and gestational week 4 and women's reproductive health outcomes.

METHODS

The Effects of Aspirin in Gestation and Reproduction trial (2007-2011) enrolled 1228 women attempting pregnancy and followed them for up to 6 menstrual cycles and throughout pregnancy if they became pregnant. We measured creatinine-adjusted, log-transformed isoprostanes 8-iso-prostaglandin F 2α (8-iso-PGF2α), its metabolite 2,3-dinor-iPF2α-III, and stereoisomers 5-iso-PGF2α-VI and 8,12-iso-iPF2α-VI in urine during preconception and 4 weeks gestation. We evaluated pregnancy among participants in each menstrual cycle using human chorionic gonadotropin (hCG) and defined pregnancy loss as observed loss following positive hCG. We calculated fecundability odds ratios (FOR) and 95% confidence intervals (CI) using discrete-time Cox proportional hazards models and relative risk of pregnancy loss using adjusted log-binomial models.

RESULTS

Higher preconception isoprostane levels were associated with lower fecundability [e.g., FOR = 0.89; 95% CI = 0.81, 0.97 per interquartile range (IQR) increase in 8-iso-PGF2α]. Among 797 pregnancies, isoprostane levels increased from preconception to 4 weeks gestation (e.g., mean difference = 0.12; 95% CI = 0.10, 0.14 ng/mL for 8-iso-PGF2α) and higher isoprostanes at 4 weeks gestation were associated with lower risk of pregnancy loss (e.g., RR = 0.79; 95% CI = 0.62, 1.00 per IQR increase in 8-iso-PGF2α).

CONCLUSIONS

Preconception urinary isoprostanes may identify redox stress pathways associated with lower fecundability. However, the increase in isoprostanes into gestational week 4 and the associated lower risk of pregnancy loss may suggest confounding by latent factors in early pregnancy.

Protein adducts with lipid peroxidation products in patients with psoriasis

Psoriasis, one of the most frequent immune-mediated skin diseases, is manifested by numerous psoriatic lessons on the skin caused by excessive proliferation and keratinization of epidermal cells. These disorders of keratinocyte metabolism are caused by a pathological interaction with the cells of the immune system, including lymphocytes, which in psoriasis are also responsible for systemic inflammation. This is accompanied by oxidative stress, which promotes the formation of lipid peroxidation products, including reactive aldehydes and isoprostanes, which are additional pro-inflammatory signaling molecules. Therefore, the presented review is focused on highlighting changes that occur during psoriasis development at the level of lipid peroxidation products, including 4-hydroxynonenal, 4-oxononenal, malondialdehyde, and acrolein, and their influence on protein structures. Furthermore, we will examine inducing agents of cellular functioning, as well as intercellular signaling. These lipid peroxidation products can form adducts with a variety of proteins with different functions in the body, including proteins within skin cells and cells of the immune system. This is especially true in autoimmune diseases such as psoriasis. For example, these changes concern proteins involved in maintaining redox homeostasis or pro-inflammatory signaling. Therefore, the formation of such adducts should attract attention, especially during the design of preventive cosmetics or anti-psoriasis therapies.

Randomized controlled trial of low vs high oxygen during neonatal anesthesia: Oxygenation, feasibility, and oxidative stress

BACKGROUND

To reduce risk for intermittent hypoxia a high fraction of inspired oxygen is routinely used during anesthesia induction. This differs from the cautious dosing of oxygen during neonatal resuscitation and intensive care and may result in significant hyperoxia.

AIM

In a randomized controlled trial, we evaluated oxygenation during general anesthesia with a low (23%) vs a high (80% during induction and recovery, and 40% during maintenance) fraction of inspired oxygen, in newborn infants undergoing surgery.

METHOD

Thirty-five newborn infants with postconceptional age of 35-44 weeks were included (17 infants in low and 18 in high oxygen group). Oxygenation was monitored by transcutaneous partial pressure of oxygen, pulse oximetry, and cerebral oxygenation. Predefined SpO2 safety targets dictated when to increase inspired oxygen.

RESULTS

At start of anesthesia, oxygenation was similar in both groups. Throughout anesthesia, the high oxygen group displayed significant hyperoxia with higher (difference-20.3 kPa, 95% confidence interval (CI)-28.4 to 12.2, p < .001) transcutaneous partial pressure of oxygen values than the low oxygen group. While SpO2 in the low oxygen group was lower (difference - 5.8%, 95% CI -9.3 to -2.4, p < .001) during anesthesia, none of the infants spent enough time below SpO₂ safety targets to mandate supplemental oxygen, and cerebral oxygenation was within the normal range and not statistically different between the groups. Analysis of the oxidative stress biomarker urinary F₂ -Isoprostane revealed no differences between the low and high oxygen group.

CONCLUSION

We conclude that in healthy newborn infants, use of low oxygen during general anesthesia was feasible, while the prevailing practice of using high levels of inspired oxygen resulted in significant hyperoxia. The trade-off between careful dosing of oxygen and risks of hypo- and hyperoxia in neonatal anesthesia should be further examined.

The Effect of β-Carotene, Tocopherols and Ascorbic Acid as Anti-Oxidant Molecules on Human and Animal In Vitro/In Vivo Studies: A Review of Research Design and Analytical Techniques Used

Prolonged elevated oxidative stress (OS) possesses negative effect on cell structure and functioning, and is associated with the development of numerous disorders. Naturally occurred anti-oxidant compounds reduce the oxidative stress in living organisms. In this review, antioxidant properties of β-carotene, tocopherols and ascorbic acid are presented based on in vitro, in vivo and populational studies. Firstly, environmental factors contributing to the OS occurrence and intracellular sources of Reactive Oxygen Species (ROS) generation, as well as ROS-mediated cellular structure degradation, are introduced. Secondly, enzymatic and non-enzymatic mechanism of anti-oxidant defence against OS development, is presented. Furthermore, ROS-preventing mechanisms and effectiveness of β-carotene, tocopherols and ascorbic acid as anti-oxidants are summarized, based on studies where different ROS-generating (oxidizing) agents are used. Oxidative stress biomarkers, as indicators on OS level and prevention by anti-oxidant supplementation, are presented with a focus on the methods (spectrophotometric, fluorometric, chromatographic, immuno-enzymatic) of their detection. Finally, the application of Raman spectroscopy and imaging as a tool for monitoring the effect of anti-oxidant (β-carotene, ascorbic acid) on cell structure and metabolism, is proposed. Literature data gathered suggest that β-carotene, tocopherols and ascorbic acid possess potential to mitigate oxidative stress in various biological systems. Moreover, Raman spectroscopy and imaging can be a valuable technique to study the effect of oxidative stress and anti-oxidant molecules in cell studies.

Biomarkers of Oxidative Stress and Antioxidant Defense

A number of reactive oxygen and nitrogen species are produced during normal metabolism in human body. These species can be both radical and non-radical and have varying degrees of reactivity. Although they have some important functions in the human body, such as contributing to signal transmission and the immune system, their presence must be balanced by the antioxidant defense system. The human body has an excellent intrinsic enzymatic antioxidant system in addition to different non-enzymatic antioxidants having small molecular masses. An extrinsic source of antioxidants are foodstuffs such as fruits, vegetables, herbs and spices, mostly rich in polyphenols. When the delicate biochemical balance between oxidants and antioxidants is disturbed in favor of oxidants, "oxidative stress" conditions emerge, under which reactive species can cause oxidative damage to biomacromolecules such as proteins, carbohydrates, lipids and DNA. This oxidative damage is often associated with cancer, aging, and neurodegenerative disorders. Because reactive species are extremely short-lived, it is almost impossible to measure their concentrations directly. Although there are certain methods such as ESR / EPR that serve this purpose, they have some disadvantages and are quite costly systems. Therefore, products generated from oxidative damage of proteins, lipids and DNA are often used to quantify the extent of oxidative damage rather than direct measurement of reactive species. These oxidative damage products are usually known as biomarkers. Determination of the concentrations of these biomarkers and changes in the concentration of protective antioxidants can provide useful information for avoiding certain diseases and keep healthy conditions.

Effect of Asymptomatic Plasmodium falciparum Parasitaemia on Platelets Thrombogenicity in Blood Donors

Currently, blood donors in Ghana are not screened for malaria parasites. Therefore, this study assessed platelet thrombogenicity in blood donors infected asymptomatically with Plasmodium falciparum and the relationship between tumour necrosis factor alpha (TNF-α), 8-iso-prostaglandin F2α oxidative stress biomarker (8-iso-PG2α), C-reactive protein (hs-CRP) and D-dimer, and platelet thrombogenes levels. Haematology analyser was used to enumerate platelet count and platelet indices in 80 P. falciparum infected blood donors and 160 matched non-infected controls. Replicate serum levels of von Willebrand Factor (vWF), platelet factor 4 (PF4), P-selectin thrombogenic factors as well as TNF-α and 8-iso-PG2α were determined using enzyme immuno-assay while high sensitive hs-CRP and D-dimer concentrations were determined by fluorescent immunoassay. The geometric mean of parasite density in malaria infected donors was 1784 parasites/µL (505-2478 parasites/µL). This led to significant increase in the mean levels of 8-iso-PG2α, hs-CRP, TNF-α and D-dimer. However, PF4, P-selectin were significantly lower in infected donors while vWF levels did not differ significantly among the groups even though lower levels were observed in the infected donors. Significant direct relationship existed between both P-selectin and PF4 and platelet count, and plateletcrit and platelet large cell ratio whereas these thrombogenic factors varied inversely to 8-iso-PG2α, TNF-α and hs-CRP. Relative thrombocytopaenia was associated with significant reduction in P-selectin and platelet factor 4 levels together with increased 8-iso-PG2α, hs-CRP, TNF-α and D-dimer levels. Taken together, it is recommended that all P. falciparum infected blood donors should be deferred.

Do Seminal Isoprostanes Have a Role in Assisted Reproduction Outcome?

F₂-isoprostanes (F₂-IsoPs), stereoisomers of prostaglandin F2α generated by the free radical-induced oxidation of arachidonic acid, have been associated with different male infertility conditions. This study aimed to evaluate the role of seminal isoprostane levels and sperm characteristics in the reproductive outcome and embryo quality of 49 infertile couples. Semen analysis was performed following WHO guidelines. Sperm chromatin maturity was detected using an aniline blue (AB) assay, and DNA integrity was assessed using the acridine orange (AO) test. Seminal F₂-IsoP levels were quantified by gas chromatography/negative ion chemical ionization tandem mass spectrometry (GC/NICI–MS/MS) analysis. Correlations among variables and their impact on in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) outcome were investigated. F₂-IsoP levels are positively correlated with double-stranded DNA sperm (p < 0.001) and negatively correlated with mature sperm chromatin (p < 0.001). Patients with positive outcomes had an increased percentage of sperm with double-stranded DNA, as did patients producing high-quality embryo, who showed higher F₂-IsoP levels compared to those detected in the low-quality embryo group. An intriguing relationship between a mild increase in F₂-IsoP levels, DNA integrity, and embryo quality seems to indicate that the non-enzymatic oxidation of arachidonic acid can be also a marker of metabolic activity in human semen.

Tomato powder is more effective than lycopene to alleviate exercise-induced lipid peroxidation in well-trained male athletes: randomized, double-blinded cross-over study

Background

Consumption of nutritional supplements to optimize recovery is gaining popularity among athletes. Tomatoes contain micronutrients and various bioactive components with antioxidant properties. Many of the health benefits of tomatoes have been attributed to lycopene encouraging athletes to consume pure lycopene supplements. The aim of this study was to compare the effect of tomato powder and lycopene supplement on lipid peroxidation induced by exhaustive exercise in well-trained male athletes.

Methods

Eleven well-trained male athletes participated in a randomized, double-blinded, crossover study. Each subject underwent three exhaustive exercise tests after 1-week supplementation of tomato powder (each serving contained 30 mg lycopene, 5.38 mg beta-carotene, 22.32 mg phytoene, 9.84 mg phytofluene), manufactured lycopene supplement (30 mg lycopene), or placebo. Three blood samples (baseline, post-ingestion and post-exercise) were collected to assess total anti-oxidant capacity (TAC) and variables of lipid peroxidation including malondialdehyde (MDA) and 8-isoprostane. Data were analyzed using repeated-measures of ANOVA at P < 0.05.

Results

Tomato powder enhanced total antioxidant capacity (12% increase, P = 0.04). Exhaustive exercise, regardless of supplement/ placebo, elevated MDA and 8-isoprostane levels (P < 0.001). The elevation of 8–isoprostane following exhaustive exercise was lower in the tomato powder treatment compared to the placebo (9% versus 24%, p = 0.01). Furthermore, following exhaustive exercise MDA elevated to a lower extent in tomatoe powder treatment compared to the placebo (20% versus 51%, p = 0.009). However, such differences were not indicated between lycopene and placebo treatments (p > 0.05).

Conclusion

Beneficial effects of tomato powder on antioxidant capacity and exercise-induced lipid peroxidation may be brought about by a synergistic interaction of lycopene with other bioactive nutrients rather than single lycopene.

Redox imbalance induced by docetaxel in the neuroblastoma SH-SY5Y cells: a study of docetaxel-induced neuronal damage

Objectives

In cancer survivors, chemotherapy-associated adverse neurological effects are described as side effects in non-targeted tissue. We investigated the role of redox-imbalance in neuronal damage by a relative low dose of Docetaxel (DTX).

Methods

The neuroblastoma cells (SH-SY5Y cells) were exposed to DTX at a dose of 1.25 nM for 6 h. Antioxidant defenses (i.e. ascorbic acid, glutathione, and catalase) and lipid oxidation products (i.e. F₂-isoprostanes) were evaluated. To investigate cell ultrastructure and tubulin localisation, transmission electron microscopy (TEM) and immunofluorescence techniques were applied.

Results

In the SH-SY5Y cells, DTX induced a significant reduction of total glutathione (P < 0.001) and ascorbic acid (P < 0.05), and an increase in both total F₂-Isoprostanes (P < 0.05) and catalase activity (P < 0.05), as compared to untreated cells. Additionally, TEM showed a significant increase in cells with apoptotic characteristics. Immunolocalisation of tubulin showed a compromised cytoskeletal organisation.

Discussion

The investigated sublethal dose of DTX, to which non-targeted cells may be exposed throughout the duration of chemotherapy treatment, induces a redox imbalance resulting in a specific modulation of the antioxidant response. This study provides new insights into DTX-induced cellular mechanisms useful for evaluating whether the concomitant use of antioxidants associated with chemotherapy mitigates chemotherapy side effects in cancer survivors.

Isoprostanes evoke contraction of the murine and human detrusor muscle via activation of the thromboxane prostanoid TP receptor and Rho kinase

Local or systemic inflammation can severely impair urinary bladder functions and contribute to the development of voiding disorders in millions of people worldwide. Isoprostanes are inflammatory lipid mediators that are upregulated in the blood and urine by oxidative stress and may potentially induce detrusor overactivity. The aim of the present study was to investigate the effects and signal transduction of isoprostanes in human and murine urinary bladders in order to provide potential pharmacological targets in detrusor overactivity. Contraction force was measured with a myograph in murine and human urinary bladder smooth muscle (UBSM) ex vivo. Isoprostane 8-iso-PGE₂ and 8-iso-PGF_2α evoked dose-dependent contraction in the murine UBSM, which was abolished in mice deficient in the thromboxane prostanoid (TP) receptor. The responses remained unaltered after removal of the mucosa or incubation with tetrodotoxin. Smooth muscle-specific deletion of Gα_12/13 protein or inhibition of Rho kinase by Y-27632 decreased the contractions. In Gα_q/11-knockout mice, responses were reduced and in the presence of Y-27632 abolished completely. In human UBSM, the TP agonist U-46619 evoked dose-dependent contractions. Neither atropine nor the purinergic receptor antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid decreased the effect, indicating that TP receptors directly mediate detrusor muscle contraction. 8-iso-PGE₂ and 8-iso-PGF_2α evoked dose-dependent contraction in the human UBSM, and these responses were abolished by the TP antagonist SQ-29548 and were decreased by Y-27632. Our results indicate that isoprostanes evoke contraction in murine and human urinary bladders, an effect mediated by the TP receptor. The G_12/13-Rho-Rho kinase pathway plays a significant role in mediating the contraction and therefore may be a potential therapeutic target in detrusor overactivity.NEW & NOTEWORTHY Voiding disorders affect millions of people worldwide. Inflammation can impair urinary bladder functions and contribute to the development of detrusor overactivity. The effects and signal transduction of inflammatory lipid mediator isoprostanes were studied in human and murine urinary bladders ex vivo. We found that isoprostanes evoke contraction, an effect mediated by thromboxane prostanoid receptors. The G_12/13-Rho-Rho kinase signaling pathway plays a significant role in mediating the contraction and therefore may be a potential therapeutic target.

Maternal Urinary Metal and Metalloid Concentrations in Association with Oxidative Stress Biomarkers

Metal exposure has been associated with a wide range of adverse birth outcomes and oxidative stress is a leading hypothesis of the mechanism of action of metal toxicity. We assessed the relationship between maternal exposure to essential and non-essential metals and metalloids in pregnancy and oxidative stress markers, and sought to identify windows of vulnerability and effect modification by fetal sex. In our analysis of 215 women from the PROTECT birth cohort study, we measured 14 essential and non-essential metals in urine samples at three time points during pregnancy. The oxidative stress marker 8-iso-prostaglandin F2α (8-iso-PGF2α) and its metabolite 2,3-dinor-5,6-dihydro-15-15-F2t-IsoP, as well as prostaglandin F2α (PGF2α), were also measured in the same urine samples. Using linear mixed models, we examined the main effects of metals on markers of oxidative stress as well as the visit-specific and fetal sex-specific effects. After adjustment for covariates, we found that a few urinary metal concentrations, most notably cesium (Cs) and copper (Cu), were associated with higher 8-iso-PGF2α with effect estimates ranging from 7.3 to 14.9% for each interquartile range, increase in the metal concentration. The effect estimates were generally in the same direction at the three visits and a few were significant only among women carrying a male fetus. Our data show that higher urinary metal concentrations were associated with elevated biomarkers of oxidative stress. Our results also indicate a potential vulnerability of women carrying a male fetus.

Connecting the "Dots": From Free Radical Lipid Autoxidation to Cell Pathology and Disease

Our understanding of lipid peroxidation in biology and medicine is rapidly evolving, as it is increasingly implicated in various diseases but also recognized as a key part of normal cell function, signaling, and death (ferroptosis). Not surprisingly, the root and consequences of lipid peroxidation have garnered increasing attention from multiple disciplines in recent years. Here we "connect the dots" between the fundamental chemistry underpinning the cascade reactions of lipid peroxidation (enzymatic or free radical), the reactive nature of the products formed (lipid-derived electrophiles), and the biological targets and mechanisms associated with these products that culminate in cellular responses. We additionally bring light to the use of highly sensitive, fluorescence-based methodologies. Stemming from the foundational concepts in chemistry and biology, these methodologies enable visualizing and quantifying each reaction in the cascade in a cellular and ultimately tissue context, toward deciphering the connections between the chemistry and physiology of lipid peroxidation. The review offers a platform in which the chemistry and biomedical research communities can access a comprehensive summary of fundamental concepts regarding lipid peroxidation, experimental tools for the study of such processes, as well as the recent discoveries by leading investigators with an emphasis on significant open questions.

Role of isoprostanes in human male infertility

One of the major causes of defective sperm function is oxidative stress, which limits the fertilizing potential of these cells as the result of collateral damage to proteins and lipids in the sperm plasma membrane. On this point, a derangement of both generation and neutralization of reactive oxygen species (ROS) is a recognized cause of male infertility. Antioxidant protection in sperm has been widely investigated, as well as the sperm composition of fatty acids (FA), which represents the preferred substrate for ROS, most frequently linked to the disease-related infertility. Isoprostanes are compounds derived from free radical-mediated oxidation of FAs. As such, they are considered an index of lipid oxidative damage and lipid mediators. This article discusses the role of isoprostanes as relevant factors both to sperm FA composition and sperm membrane integrity. Additionally, isoprostane's influence on sperm quality is reviewed. With reference to male reproductive dysfunction, increasing evidence indicates isoprostanes, detectable in biological fluids or sperm membrane, as the specific index of 1) exposure to chemical etiological agents, 2) oxidative damage, 3) reduced antioxidant response, and 4) sperm immaturity.

ABBREVIATIONS

OS: oxidative stress; ROS: reactive oxygen species; PUFAs: polyunsaturated fatty acids; ARA: arachidonic acid, F₂-IsoPs; F₂-isoprostanes, PLA₂: phospholipase A₂; NADPH: nicotinamide adenine dinucleotide phosphate; IVF: in vitro fertilization.

Association between High On-Aspirin Platelet Reactivity and Reduced Superoxide Dismutase Activity in Patients Affected by Type 2 Diabetes Mellitus or Primary Hypercholesterolemia

Platelet hyperactivation is involved in the established prothrombotic condition of metabolic diseases such as Type 2 Diabetes Mellitus (T2DM) and familial hypercholesterolemia (HC), justifying the therapy with aspirin, a suppressor of thromboxane synthesis through the irreversible inhibition of cyclooxygenase-1 (COX-1), to prevent cardiovascular diseases. However, some patients on aspirin show a higher than expected platelet reactivity due, at least in part, to a pro-oxidant milieu. The aim of this study was to investigate platelet reactivity in T2DM (n = 103) or HC (n = 61) patients (aspirin, 100 mg/day) and its correlation with biomarkers of redox function including the superoxide anion scavenger superoxide dismutase (SOD) and the in vivo marker of oxidative stress urinary 8-iso-prostaglandin F_2α. As results, in T2DM and HC subjects the prevalence of high on-aspirin platelet reactivity was comparable when both non-COX-1-dependent and COX-1-dependent assays were performed, and platelet reactivity is associated with a lower SOD activity that in a stepwise linear regression appears as the only predictor of platelet reactivity. To conclude, in T2DM and HC, similarly, the impairment of redox equilibrium associated with a decrease of SOD activity could contribute to a suboptimal response to aspirin.

Urinary Markers of Oxidative Stress in Children with Autism Spectrum Disorder (ASD)

Background: Autism spectrum disorder (ASD) is a developmental disorder characterized by deficits in social interaction, restricted interest and repetitive behavior. Oxidative stress in response to environmental exposure plays a role in virtually every human disease and represents a significant avenue of research into the etiology of ASD. The aim of this study was to explore the diagnostic utility of four urinary biomarkers of oxidative stress. Methods: One hundred and thirty-nine (139) children and adolescents with ASD (89% male, average age = 10.0 years, age range = 2.1 to 18.1 years) and 47 healthy children and adolescents (49% male, average age 9.2, age range = 2.5 to 20.8 years) were recruited for this study. Their urinary 8-OH-dG, 8-isoprostane, dityrosine and hexanoil-lisine were determined by using the ELISA method. Urinary creatinine was determined with the kinetic Jaffee reaction and was used to normalize all biochemical measurements. Non-parametric tests and support vector machines (SVM) with three different kernel functions (linear, radial, polynomial) were used to explore and optimize the multivariate prediction of an ASD diagnosis based on the collected biochemical measurements. The SVM models were first trained using data from a random subset of children and adolescents from the ASD group (n = 70, 90% male, average age = 9.7 years, age range = 2.1 to 17.8 years) and the control group (n = 24, 45.8% male, average age = 9.4 years, age range = 2.5 to 20.8 years) using bootstrapping, with additional synthetic minority over-sampling (SMOTE), which was utilized because of unbalanced data. The computed SVM models were then validated using the remaining data from children and adolescents from the ASD (n = 69, 88% male, average age = 10.2 years, age range = 4.3 to 18.1 years) and the control group (n = 23, 52.2% male, average age = 8.9 years, age range = 2.6 to 16.7 years). Results: Using a non-parametric test, we found a trend showing that the urinary 8-OH-dG concentration was lower in children with ASD compared to the control group (unadjusted p = 0.085). When all four biochemical measurements were combined using SVMs with a radial kernel function, we could predict an ASD diagnosis with a balanced accuracy of 73.4%, thereby accounting for an estimated 20.8% of variance (p < 0.001). The predictive accuracy expressed as the area under the curve (AUC) was solid (95% CI = 0.691-0.908). Using the validation data, we achieved significantly lower rates of classification accuracy as expressed by the balanced accuracy (60.1%), the AUC (95% CI = 0.502-0.781) and the percentage of explained variance (R² = 3.8%). Although the radial SVMs showed less predictive power using the validation data, they do, together with ratings of standardized SVM variable importance, provide some indication that urinary levels of 8-OH-dG and 8-isoprostane are predictive of an ASD diagnosis. Conclusions: Our results indicate that the examined urinary biomarkers in combination may differentiate children with ASD from healthy peers to a significant extent. However, the etiological importance of these findings is difficult to assesses, due to the high-dimensional nature of SVMs and a radial kernel function. Nonetheless, our results show that machine learning methods may provide significant insight into ASD and other disorders that could be related to oxidative stress.

Utility of hemoglobin A1c in detecting risk of type 2 diabetes: comparison of hemoglobin A1c with other biomarkers

We have previously reported that the risk of type 2 diabetes, early impaired glucose tolerance, and insulin resistance can be predicted using fasting levels of adiponectin, leptin, and insulin. Here, we aimed to evaluate the utility of hemoglobin A1c in detecting the risk of type 2 diabetes compared with other well-known biomarkers. We randomly enrolled 207 volunteers with no history of diseases, who underwent 75-g oral glucose tolerance tests and were stratified into normal, borderline, abnormal, or diabetic groups. Eighty-one participants with normal baseline levels of hemoglobin A1c (<6.0%) were included in the normal groups of both glucose tolerance and insulin resistance. Hemoglobin A1c was significantly correlated with the plasma glucose and insulin resistance index. Leptin, adiponectin, glycoalbumin, and body mass index also were correlated well with plasma glucose levels and insulin resistance index. Normal hemoglobin A1c levels with abnormal glucose tolerance and insulin resistance were noted in 85 and 67 participants, respectively. Hemoglobin A1c did not strengthen the prediction algorithm of diabetes, determined by our proposed biomarkers, leptin, adiponectin, and insulin. In conclusion, hemoglobin A1c is a surrogate biomarker for risk of diabetes, with inadequate predictive value, and should be used in combination with other biomarkers.

Effects of Virgin Olive Oils Differing in Their Bioactive Compound Contents on Biomarkers of Oxidative Stress and Inflammation in Healthy Adults: A Randomized Double-Blind Controlled Trial

A regular consumption of virgin olive oil (VOO) is associated with a reduced risk of cardiovascular disease. We aimed to assess whether the raw intake of an optimized VOO (OVOO, 490 ppm of phenolic compounds and 86 ppm of triterpenes), and a functional olive oil (FOO, 487 ppm of phenolic compounds and enriched with 389 ppm of triterpenes) supplementation (30 mL per day) during three weeks would provide additional health benefits to those produced by a standard VOO (124 ppm of phenolic compounds and 86 ppm of triterpenes) on oxidative and inflammatory biomarkers. Fifty-one healthy adults participated in a randomized, crossover, and controlled study. Urinary 8-hidroxy-2′-deoxyguanosine, plasma interleukin-8 (IL-8), and tumor necrosis factor α (TNF- α) concentrations were lower after the intervention with the FOO than after the OVOO (p = 0.033, p = 0.011 and p = 0.020, respectively). In addition, IL-8 was lower after the intervention with FOO than after VOO intervention (p = 0.002). This study provides a first level of evidence on the in vivo health benefits of olive oil triterpenes (oleanolic and maslinic acids) in healthy humans, decreasing DNA oxidation and plasma inflammatory biomarkers. The trial was registered in ClinicalTrials.gov ID: NCT02520739.

The lipid peroxidation in patients with nephrolithiasis before and after extracorporeal shock wave lithotripsy

AIM

To evaluate the level of lipid peroxidation in patients with nephrolithiasis before and after extracorporeal shock wave lithotripsy (ESWL).

MATERIALS & METHODS

Isoprostane concentration (8-isoPGF_2α) was measured in urine, and thiobarbituric acid reactive substance production in serum and erythrocytes. In addition, the concentrations of selected compounds (uric acid, glucose and creatinine) were measured in serum.

RESULTS

The patients (before and after ESWL) demonstrated significantly higher levels of two different biomarkers of lipid peroxidation compared with the control group. A correlation was identified between increased amounts of uric acid and biomarkers of lipid peroxidation in patients with nephrolithiasis, both before and after ESWL.

CONCLUSION

Uric acid may be associated with lipid peroxidation in patients with nephrolithiasis.

Isoprostanoids in Clinical and Experimental Neurological Disease Models

Isoprostanoids are a large family of compounds derived from non-enzymatic oxidation of polyunsaturated fatty acids (PUFAs). Unlike other oxidative stress biomarkers, they provide unique information on the precursor of the targeted PUFA. Although they were discovered about a quarter of century ago, the knowledge on the role of key isoprostanoids in the pathogenesis of experimental and human disease models remains limited. This is mainly due to the limited availability of highly purified molecules to be used as a reference standard in the identification of biological samples. The accurate knowledge on their biological relevance is the critical step that could be translated from some mere technical/industrial advances into a reliable biological disease marker which is helpful in deciphering the oxidative stress puzzle related to neurological disorders. Recent research indicates the value of isoprostanoids in predicting the clinical presentation and evolution of the neurological diseases. This review focuses on the relevance of isoprostanoids as mediators and potential biomarkers in neurological diseases, a heterogeneous family ranging from rare brain diseases to major health conditions that could have worldwide socioeconomic impact in the health sector. The current challenge is to identify the preferential biochemical pathways that actually follow the oxidative reactions in the neurological diseases and the consequence of the specific isoprostanes in the underlying pathogenic mechanisms.

The Role of Oxidative Stress and Membrane Transport Systems during Endometriosis: A Fresh Look at a Busy Corner

Endometriosis is a condition characterized by the presence of endometrial tissue outside the uterine cavity, leading to a chronic inflammatory reaction. It is one of the most widespread gynecological diseases with a 10-15% prevalence in the general female population, rising up to 30-45% in patients with infertility. Although it was first described in 1860, its etiology and pathogenesis are still unclear. It is now accepted that inflammation plays a central role in the development and progression of endometriosis. In particular, it is marked by an inflammatory process associated with the overproduction of an array of inflammatory mediators such as prostaglandins, metalloproteinases, cytokines, and chemokines. In addition, the growth and adhesion of endometrial cells in the peritoneal cavity due to reactive oxygen species (ROS) and free radicals lead to disease onset, its ensuing symptoms-among which pain and infertility. The aim of our review is to evaluate the role of oxidative stress and ROS in the pathogenesis of endometriosis and the efficacy of antioxidant therapy in the treatment and mitigation of its symptoms.

Increased F2-Isoprostane Levels in Semen and Immunolocalization of the 8-Iso Prostaglandin F2α in Spermatozoa from Infertile Patients with Varicocele

Polyunsaturated fatty acid damages lead to alterations in sperm function. This study aimed to investigate the involvement of F₂-isoprostanes (F₂-IsoPs), oxidized lipid products from arachidonic acid, in sperm quality impairment. For this purpose, F₂-IsoP levels in semen and F₂-IsoP localization in spermatozoa were explored in infertile subjects affected by idiopathic infertility or varicocele, as well as in fertile men. As compared to fertile men, in the idiopathic infertility and varicocele groups, sperm concentration, motility, morphology, viability, and fertility index were significantly lower and the mean scores concerning sperm apoptosis, necrosis, and immaturity were significantly higher. The idiopathic infertile group showed a reduction in sperm motility and fertility index, as well as an increase of apoptosis and necrosis percentages, in comparison to the varicocele group. The varicocele group showed the highest levels of F₂-IsoPs, a significant increase of sperm immaturity, and a significant correlation between F₂-IsoP levels and sperm immaturity. 8-Iso Prostaglandin F_2α, biomarker of in vivo F₂-IsoP, was clearly localized in sperm midpiece and cytoplasmic residues. Data show that F₂-IsoP formation is relevant in semen and sperm from infertile patients with varicocele and high percentage of immaturity, suggesting that a correct fatty acid integrity is needed for sperm maturation.

Sleep duration, nightshift work, and the timing of meals and urinary levels of 8-isoprostane and 6-sulfatoxymelatonin in Japanese women

It has been hypothesized that disruption of circadian rhythms affects human health. Shift work and sleep deprivation are thought to disrupt the normal light-dark cycle, although the disruption due to shiftwork may be dependent on sleep deprivation. Both conditions have been suggested to be associated with an increased risk of cardiometabolic disorders. Non-photic environmental factors, such as the timing of eating, are also thought to regulate circadian rhythm and thus, may have effects on health, but the evidence from human studies is scarce. Oxidative stress is a risk factor of cardiometabolic disorders. Some laboratory studies suggest an involvement of circadian clock genes in the regulation of the redox system. The present study aimed to examine the association of sleeping habits, nightshift work, and the timing of meals with urinary levels of 8-isoprostane, a marker of oxidative stress, and 6-sulfatoxymelatonin, the principal metabolite of melatonin. Study subjects were 542 women who had previously attended a breast cancer mass screening in a community in Japan. Information on bedtimes and wake-up times, history of nightshift work, and the timing of meals was obtained by a self-administered questionnaire. The 8-isoprostane and 6-sulfatoxymelatonin were measured using the first morning void of urine and expressed per mg of creatinine. The geometric mean of 8-isoprostane levels was 12.1% higher in women with ≤6 hours of sleep than that in those with >8 hours of sleep on weekdays, and longer sleep duration on weekdays was significantly associated with lower urinary levels of 8-isoprostane after controlling for covariates (p for trend = 0.04). Women who were currently working the nightshift had a 33.3% higher geometric mean of 8-isoprostane levels than those who were not working nightshift (p = 0.03). Urinary 6-sulfatoxymelatonin levels were unrelated to sleep habits or nightshift work. Women who ate breakfast at irregular times had a 19.8% higher geometric mean of 8-isoprostane levels than those who ate breakfast at a regular time or who did not eat (p = 0.02). Women who ate nighttime snacks at irregular times had a 16.2% higher geometric mean of 8-isoprostane levels than those who did not eat nighttime snacks or who ate nighttime snacks at a regular time (p = 0.003). Among women who ate dinner at a regular time, earlier times for dinner were associated with higher 8-isoprostane and 6-sulfatoxymelatonin levels (p values for trends were 0.01 and 0.02, respectively). However, the times of dinner and nighttime snack are overlapping, and the time of last meal of the day was not associated with 8-isoprostane and 6-sulfatoxymelatonin levels. The time of breakfast or lunch was not associated with these biomarkers among women who ate the meal at regular times. Disturbing the rhythmicity of daily life may be associated with oxidative stress.

The enigma ofin vivooxidative stress assessment: isoprostanes as an emerging target

Oxidative stress is believed to be one of the major factors behind several acute and chronic diseases, and may also be associated with ageing. Excess formation of free radicals in miscellaneous body environment may originate from endogenous response to cell injury, but also from exposure to a number of exogenous toxins. When the antioxidant defence system is overwhelmed, this leads to cell damage. However, the measurement of free radicals or their endproducts is tricky, since these compounds are reactive and short lived, and have diverse characteristics. Specific evidence for the involvement of free radicals in pathological situations has been difficult to obtain, partly owing to shortcomings in earlier described methods for the measurement of oxidative stress. Isoprostanes, which are prostaglandin-like bioactive compounds synthesized in vivo from oxidation of arachidonic acid, independently of cyclooxygenases, are involved in many human diseases, and their measurement therefore offers a way to assess oxidative stress. Elevated levels of F₂-isoprostanes have also been seen in the normal human pregnancy, but their physiological role has not yet been defined. Large amounts of bioactive F₂-isoprostanes are excreted in the urine in normal basal situations, with a wide interindividual variation. Their exact role in the regulation of normal physiological functions, however, needs to be explored further. Current understanding suggests that measurement of F₂-isoprostanes in body fluids provides a reliable analytical tool to study oxidative stress-related diseases and experimental inflammatory conditions, and also in the evaluation of various dietary antioxidants, as well as drugs with radical-scavenging properties. However, assessment of isoprostanes in plasma or urine does not necessarily reflect any specific tissue damage, nor does it provide information on the oxidation of lipids other than arachidonic acid.

The importance of antioxidants which play the role in cellular response against oxidative/nitrosative stress: current state

Remarkable interest has risen in the idea that oxidative/nitrosative stress is mediated in the etiology of numerous human diseases. Oxidative/Nitrosative stress is the result of an disequilibrium in oxidant/antioxidant which reveals from continuous increase of Reactive Oxygen and Reactive Nitrogen Species production. The aim of this review is to emphasize with current information the importance of antioxidants which play the role in cellular responce against oxidative/nitrosative stress, which would be helpful in enhancing the knowledge of any biochemist, pathophysiologist, or medical personnel regarding this important issue. Products of lipid peroxidation have commonly been used as biomarkers of oxidative/nitrosative stress damage. Lipid peroxidation generates a variety of relatively stable decomposition end products, mainly α, β-unsaturated reactive aldehydes, such as malondialdehyde, 4-hydroxy-2-nonenal, 2-propenal (acrolein) and isoprostanes, which can be measured in plasma and urine as an indirect index of oxidative/nitrosative stress. Antioxidants are exogenous or endogenous molecules that mitigate any form of oxidative/nitrosative stress or its consequences. They may act from directly scavenging free radicals to increasing antioxidative defences. Antioxidant deficiencies can develop as a result of decreased antioxidant intake, synthesis of endogenous enzymes or increased antioxidant utilization. Antioxidant supplementation has become an increasingly popular practice to maintain optimal body function. However, antoxidants exhibit pro-oxidant activity depending on the specific set of conditions. Of particular importance are their dosage and redox conditions in the cell.

Elevated 8-Isoprostane Levels in Basal Cell Carcinoma and in Uva Irradiated Skin

Isoprostanes are prostaglandin isomers produced from the peroxidation of polyunsaturated fatty acids from the cellular membrane. They have been used as a specific index of cellular lipoperoxidation and as an indirect measure of oxidative stress. However, these molecules also present several biological activities. An oxidative environment measured as the presence of other indirect measurements of reactive oxygen species lipoperoxidation has recently been described in basal cell carcinoma, the most frequent type of non-melanoma skin cancer. This study aims to measure the levels of 8-isoprostaglandin F2α, an isoprostane widely studied in other models as a by-product of ROS-induced lipid peroxidation, in basal cell carcinoma and in UVA irradiated healthy skin. We found that 8-iso-PGF2α is present in higher levels in BCC specimens compared to healthy non sun-exposed skin, confirming previous studies on the production of lipoperoxidation in this tumor. Moreover, we demonstrated that topical pre-treatment with a compound containing vitamin E is capable of reducing 8-iso-PGF2α formation in UV irradiated skin suggesting a role for isoprostanes in UV induced inflammation and eventually carcinogenesis and confirming the function of vitamin E as an antioxidant in this model.

Beneficial effect of refined red palm oil on lipid peroxidation and monocyte tissue factor in HCV-related liver disease: a randomized controlled study

BACKGROUND

A large amount of endotoxin can be detected in the peripheral venous blood of patients with liver cirrhosis, contributing to the pathogenesis of hepatotoxicity because of its role in oxidative stress. The present study aimed to test the effect of the supplementation with red palm oil (RPO), which is a natural oil obtained from oil palm fruit (Elaeis guineensis) rich in natural fat-soluble tocopherols, tocotrienols and carotenoids, on lipid peroxidation and endotoxemia with plasma endotoxin-inactivating capacity, proinflammatory cytokines profile, and monocyte tissue factor in patients with chronic liver disease.

METHODS

The study group consisted of sixty patients (34 males and 26 females; mean age 62 years, range 54-75) with Child A/B, genotype 1 HCV-related cirrhosis without a history of ethanol consumption, randomly enrolled into an 8-week oral daily treatment with either vitamin E or RPO. All patients had undergone an upper gastrointestinal endoscopy 8 months before, and 13 out of them showed esophageal varices.

RESULTS

Both treatments significantly decreased erythrocyte malondialdehyde and urinary isoprostane output, only RPO significantly affected macrophage-colony stimulating factor and monocyte tissue factor. Liver ultrasound imaging did not show any change.

CONCLUSIONS

RPO beneficially modulates oxidative stress and, not least, downregulates macrophage/monocyte inflammatory parameters. RPO can be safely advised as a valuable nutritional implementation tool in the management of chronic liver diseases.

Peroxidised dietary lipids impair intestinal function and morphology of the small intestine villi of nursery pigs in a dose-dependent manner

The objective of this study was to investigate the effect of increasing degrees of lipid peroxidation on structure and function of the small intestine of nursery pigs. A total of 216 pigs (mean body weight was 6·5 kg) were randomly allotted within weight blocks and sex and fed one of five experimental diets for 35 d (eleven pens per treatment with three to four pigs per pen). Treatments included a control diet without added lipid, and diets supplemented with 6 % soyabean oil that was exposed to heat (80°C) and constant oxygen flow (1 litre/min) for 0, 6, 9 and 12 d. Increasing lipid peroxidation linearly reduced feed intake (P<0·001) and weight gain (P=0·024). Apparent faecal digestibility of gross energy (P=0·001) and fat (P<0·001) decreased linearly as the degree of peroxidation increased. Absorption of mannitol (linear,P=0·097) andd-xylose (linear,P=0·089), measured in serum 2 h post gavage with a solution containing 0·2 g/ml ofd-xylose and 0·3 g/ml of mannitol, tended to decrease progressively as the peroxidation level increased. Increasing peroxidation also resulted in increased villi height (linear,P<0·001) and crypt depth (quadratic,P=0·005) in the jejunum. Increasing peroxidation increased malondialdehyde concentrations (quadratic,P=0·035) and reduced the total antioxidant capacity (linear,P=0·044) in the jejunal mucosa. In conclusion, lipid peroxidation progressively diminished animal performance and modified the function and morphology of the small intestine of nursery pigs. Detrimental effects were related with the disruption of redox environment of the intestinal mucosa.

Multi-Biomarkers for Early Detection of Type 2 Diabetes, Including 10- and 12-(Z,E)-Hydroxyoctadecadienoic Acids, Insulin, Leptin, and Adiponectin

We have previously found that fasting plasma levels of totally assessed 10- and 12-(Z,E)-hydroxyoctadecadienoic acid (HODE) correlated well with levels of glycated hemoglobin (HbA1c) and glucose during oral glucose tolerance tests (OGTT); these levels were determined via liquid chromatography—mass spectrometry after reduction and saponification. However, 10- and 12-(Z,E)-HODE alone cannot perfectly detect early impaired glucose tolerance (IGT) and/or insulin resistance, which ultimately lead to diabetes. In this study, we randomly recruited healthy volunteers (n = 57) who had no known history of any diseases, and who were evaluated using the OGTT, the HODE biomarkers, and several additional proposed biomarkers, including retinol binding protein 4 (RBP4), adiponectin, leptin, insulin, glycoalbumin, and high sensitivity-C-reactive protein. The OGTT revealed that our volunteers included normal individuals (n = 44; Group N), “high-normal” individuals (fasting plasma glucose 100–109 mg/dL) with IGT (n = 11; Group HN+IGT), and diabetic individuals (n = 2; Group D). We then used these groups to evaluate the potential biomarkers for the early detection of type 2 diabetes. Plasma levels of RBP4 and glycoalbumin were higher in Group HN+IGT, compared to those in Group N, and fasting levels of 10- and 12-(Z,E)-HODE/linoleic acids were significantly correlated with levels of RBP4 (p = 0.003, r = 0.380) and glycoalbumin (p = 0.006, r = 0.316). Furthermore, we developed a stepwise multiple linear regression models to predict the individuals’ insulin resistance index (the Matsuda Index 3). Fasting plasma levels of 10- and 12-(Z,E)-HODE/linoleic acids, glucose, insulin, and leptin/adiponectin were selected as the explanatory variables for the models. The risks of type 2 diabetes, early IGT, and insulin resistance were perfectly predicted by comparing fasting glucose levels to the estimated Matsuda Index 3 (fasting levels of 10- and 12-(Z,E)-HODE/linoleic acids, insulin, and leptin/adiponectin).

A Proposed Molecular Mechanism of High-Dose Vitamin D3 Supplementation in Prevention and Treatment of Preeclampsia

A randomized prospective clinical study performed on a group of 74 pregnant women (43 presenting with severe preeclampsia) proved that urinary levels of 15-F(2t)-isoprostane were significantly higher in preeclamptic patients relative to the control (3.05 vs. 2.00 ng/mg creatinine). Surprisingly enough, plasma levels of 25-hydroxyvitamin D3 in both study groups were below the clinical reference range with no significant difference between the groups. In vitro study performed on isolated placental mitochondria and placental cell line showed that suicidal self-oxidation of cytochrome P450scc may lead to structural disintegration of heme, potentially contributing to enhancement of oxidative stress phenomena in the course of preeclampsia. As placental cytochrome P450scc pleiotropic activity is implicated in the metabolism of free radical mediated arachidonic acid derivatives as well as multiple Vitamin D3 hydroxylations and progesterone synthesis, we propose that Vitamin D3 might act as a competitive inhibitor of placental cytochrome P450scc preventing the production of lipid peroxides or excess progesterone synthesis, both of which may contribute to the etiopathogenesis of preeclampsia. The proposed molecular mechanism is in accord with the preliminary clinical observations on the surprisingly high efficacy of high-dose Vitamin D3 supplementation in prevention and treatment of preeclampsia.

F2-isoprostanes are correlated with trans fatty acids in the plasma of pregnant women

We hypothesized that the mild physiological oxidative stress present during pregnancy could increase both, plasma F2-isoprostanes (F2-isoPs) by lipid oxidation and trans fatty acids (TFA) through cis-trans isomerization respectively. Plasma samples collected at 12-18 weeks (MIROS cohort; n=65) and 38-41 weeks of pregnancy (CHUL cohort; n=21) were subjected to alkaline hydrolysis followed by liquid-liquid extraction in order to extract total F2-isoPs for quantification by HPLC-MS/MS. Several positive correlations were found between F2-isoPs and TFA, measured by GC-FID in plasma phospholipids, such as 6t-18:1, 9t-18:1 and 9t,12c-18:2 (r>0.306; p<0.045). Despite its low level, the 9t,12c-18:2 trans isomer, known to be associated to cardiovascular diseases, showed the most significant correlations with F2-isoPs. No correlation was observed between F2-isoPs and 9t-16:1 or 11t-18:1. In summary, this study suggests either a concomitant phenomenon or a competition between lipid peroxidation and cis-trans isomerisation of the cis precursor fatty acid in vivo during pregnancy.

Oxidative stress and its biomarkers in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune inflammatory disease whose etiology remains largely unknown. The uncontrolled oxidative stress in SLE contributes to functional oxidative modifications of cellular protein, lipid and DNA and consequences of oxidative modification play a crucial role in immunomodulation and trigger autoimmunity. Measurements of oxidative modified protein, lipid and DNA in biological samples from SLE patients may assist in the elucidation of the pathophysiological mechanisms of the oxidative stress-related damage, the prediction of disease prognosis and the selection of adequate treatment in the early stage of disease. Application of these biomarkers in disease may indicate the early effectiveness of the therapy. This review is intended to provide an overview of various reactive oxygen species (ROS) formed during the state of disease and their biomarkers linking with disease. The first part of the review presents biochemistry and pathophysiology of ROS and antioxidant system in disease. The second part of the review discusses the recent development of oxidative stress biomarkers that relates pathogenesis in SLE patients and animal model. Finally, this review also describes the reported clinical trials of antioxidant in the disease that have evaluated the efficacy of antioxidant in the management of disease with ongoing conventional therapy.

Antioxidant supplements reduced oxidative stress and stabilized liver function tests but did not reduce inflammation in a randomized controlled trial in obese children and adolescents

Oxidative stress and low-grade systemic inflammation may contribute to the pathogenesis of obesity-induced comorbidities, including nonalcoholic fatty liver disease. Increasing intake of dietary antioxidants might be beneficial, but there are few data in obese children. To examine the effect of antioxidant supplementation on biomarkers of oxidative stress, inflammation, and liver function, we randomly assigned overweight or obese children and adolescents (n = 44; mean ± SD age: 12.7 ± 1.5 y) participating in a lifestyle modification program to a 4-mo intervention with daily antioxidants (vitamin E, 400 IU; vitamin C, 500 mg; selenium, 50 μg) or placebo. We measured anthropometrics, antioxidant status, oxidative stress (F(2)-isoprostanes, F(2)-isoprostane metabolites), inflammation, liver enzymes, fasting insulin and glucose, and lipid profile at baseline and endpoint. There was a significant treatment effect of antioxidant supplementation on antioxidant status [α-tocopherol, β = 23.2 (95% CI: 18.0, 28.4); ascorbic acid, β = 70.6 (95% CI: 51.7, 89.4); selenium, β = 0.07 (95% CI: 0.01, 0.12)] and oxidative stress [8-iso-prostaglandin F2α, β = -0.11 (95% CI: -0.19, -0.02)] but not on any of the inflammatory markers measured. There was a significant treatment effect on alanine aminotransferase [β = -0.13 (95% CI: -0.23, -0.03)], a trend toward a significant effect on aspartate aminotransferase [β = -0.04 (95% CI: -0.09, 0.01)], and no significant effect on γ-glutamyltransferase [β = -0.03 (95% CI: -0.11, 0.06)]. In summary, antioxidant supplementation for 4 mo improved antioxidant-oxidant balance and modestly improved liver function tests; however, it did not reduce markers of systemic inflammation despite significant baseline correlations between oxidative stress and inflammation. The study was registered at clinicaltrials.gov as NCT01316081.

Positive and negative effects of prostaglandins in Alzheimer's disease

The aim of this review was to clarify the role of prostaglandins and prostaglandin receptors in the immunopathology of Alzheimer's disease. A PubMed search was done using the key word, 'Alzheimer's disease' in combination with the term 'prostaglandins'. Articles from the past 10 years were preferentially selected but important ones from the past 20 years were also included according to the authors' judgment. Alzheimer's disease is characterized by pathological hallmarks such as extracellular deposition of the amyloid β-peptide, the appearance of intracellular neurofibrillary tangles, extensive neuronal loss and synaptic changes in the cerebral cortex and hippocampus. These processes induce inflammatory pathways by activating microglia, astrocytes and infiltrating leukocytes that produce inflammatory mediators including cytokines and prostaglandins.Prostaglandins are small lipid mediators derived from arachidonic acid by multi-enzymatic pathways in which cyclooxygenases and phospholipases are the rate-limiting enzymes. In the central nervous system, prostaglandins exhibit either neurotoxic or neuroprotective effects by acting on specific G-protein-coupled receptors that have different subfamilies and differences in their selective agonists, tissue distribution and signal transduction cascades. Further studies on the role of prostaglandins in Alzheimer's disease may contribute to clarification of their neuroprotective actions, which may lead to the development of successful therapeutic strategies.

Reactive carbonyl species and their roles in sarcoplasmic reticulum Ca2+ cycling defect in the diabetic heart

Efficient and rhythmic cardiac contractions depend critically on the adequate and synchronized release of Ca(2+) from the sarcoplasmic reticulum (SR) via ryanodine receptor Ca(2+) release channels (RyR2) and its reuptake via sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2a). It is well established that this orchestrated process becomes compromised in diabetes. What remain incompletely defined are the molecular mechanisms responsible for the dysregulation of RyR2 and SERCA2a in diabetes. Earlier, we found elevated levels of carbonyl adducts on RyR2 and SERCA2a isolated from hearts of type 1 diabetic rats and showed the presence of these posttranslational modifications compromised their functions. We also showed that these mono- and di-carbonyl reactive carbonyl species (RCS) do not indiscriminately react with all basic amino acid residues on RyR2 and SERCA2a; some residues are more susceptible to carbonylation (modification by RCS) than others. A key unresolved question in the field is which of the many RCS that are upregulated in the heart in diabetes chemically react with RyR2 and SERCA2a? This brief review introduces readers to the field of RCS and their roles in perturbing SR Ca(2+) cycling in diabetes. It also provides new experimental evidence that not all RCS that are upregulated in the heart in diabetes chemically react with RyR2 and SERCA2a, methylglyoxal and glyoxal preferentially do.

Clinical perspective on oxidative stress in sporadic amyotrophic lateral sclerosis

Sporadic amyotrophic lateral sclerosis (ALS) is one of the most devastating neurological diseases; most patients die within 3 to 4 years after symptom onset. Oxidative stress is a disturbance in the pro-oxidative/antioxidative balance favoring the pro-oxidative state. Autopsy and laboratory studies in ALS indicate that oxidative stress plays a major role in motor neuron degeneration and astrocyte dysfunction. Oxidative stress biomarkers in cerebrospinal fluid, plasma, and urine are elevated, suggesting that abnormal oxidative stress is generated outside of the central nervous system. Our review indicates that agricultural chemicals, heavy metals, military service, professional sports, excessive physical exertion, chronic head trauma, and certain foods might be modestly associated with ALS risk, with a stronger association between risk and smoking. At the cellular level, these factors are all involved in generating oxidative stress. Experimental studies indicate that a combination of insults that induce modest oxidative stress can exert additive deleterious effects on motor neurons, suggesting that multiple exposures in real-world environments are important. As the disease progresses, nutritional deficiency, cachexia, psychological stress, and impending respiratory failure may further increase oxidative stress. Moreover, accumulating evidence suggests that ALS is possibly a systemic disease. Laboratory, pathologic, and epidemiologic evidence clearly supports the hypothesis that oxidative stress is central in the pathogenic process, particularly in genetically susceptive individuals. If we are to improve ALS treatment, well-designed biochemical and genetic epidemiological studies, combined with a multidisciplinary research approach, are needed and will provide knowledge crucial to our understanding of ALS etiology, pathophysiology, and prognosis.

Myalgic encephalomyelitis/chronic fatigue syndrome and encephalomyelitis disseminata/multiple sclerosis show remarkable levels of similarity in phenomenology and neuroimmune characteristics

BACKGROUND

'Encephalomyelitis disseminata' (multiple sclerosis) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are both classified as diseases of the central nervous system by the World Health Organization. This review aims to compare the phenomenological and neuroimmune characteristics of MS with those of ME/CFS.

DISCUSSION

There are remarkable phenomenological and neuroimmune overlaps between both disorders. Patients with ME/CFS and MS both experience severe levels of disabling fatigue and a worsening of symptoms following exercise and resort to energy conservation strategies in an attempt to meet the energy demands of day-to-day living. Debilitating autonomic symptoms, diminished cardiac responses to exercise, orthostatic intolerance and postural hypotension are experienced by patients with both illnesses. Both disorders show a relapsing-remitting or progressive course, while infections and psychosocial stress play a large part in worsening of fatigue symptoms. Activated immunoinflammatory, oxidative and nitrosative (O+NS) pathways and autoimmunity occur in both illnesses. The consequences of O+NS damage to self-epitopes is evidenced by the almost bewildering and almost identical array of autoantibodies formed against damaged epitopes seen in both illnesses. Mitochondrial dysfunctions, including lowered levels of ATP, decreased phosphocreatine synthesis and impaired oxidative phosphorylation, are heavily involved in the pathophysiology of both MS and ME/CFS. The findings produced by neuroimaging techniques are quite similar in both illnesses and show decreased cerebral blood flow, atrophy, gray matter reduction, white matter hyperintensities, increased cerebral lactate and choline signaling and lowered acetyl-aspartate levels.

SUMMARY

This review shows that there are neuroimmune similarities between MS and ME/CFS. This further substantiates the view that ME/CFS is a neuroimmune illness and that patients with MS are immunologically primed to develop symptoms of ME/CFS.

Extracorporeal blood oxygenation and ozonation: clinical and biological implications of ozone therapy

Some lines of evidence have suggested that the challenge to antioxidants and biomolecules provoked by pro-oxidants such as ozone may be used to generate a controlled stress response of possible therapeutic relevance in some immune dysfunctions and chronic, degenerative conditions. Immune and endothelial cells have been proposed to be elective targets of the positive molecular effects of ozone and its derived species formed during blood ozonation. On the bases of these underlying principles and against often prejudicial scepticism and concerns about its toxicity, ozone has been used in autohemotherapy (AHT) for four decades with encouraging results. However, clinical application and validation of AHT have been so far largely insufficient. Latterly, a new and more effective therapeutic approach to ozone therapy has been established, namely extracorporeal blood oxygenation and ozonation (EBOO). This technique, first tested in vitro and then in vivo in sheep and humans (more than 1200 treatments performed in 82 patients), is performed with a high-efficiency apparatus that makes it possible to treat with a mixture of oxygen-ozone (0.5-1 microg/ml oxygen) in 1 h of extracorporeal circulation up to 4800 ml of heparinized blood without technical or clinical problems, whereas only 250 ml of blood can be treated with ozone by AHT. The EBOO technique can be easily adapted for use in hemodialysis also. The standard therapeutic cycle lasts for 7 weeks in which 14 treatment sessions of 1 h are performed. After a session of EBOO, the interaction of ozone with blood components results in 4-5-fold increased levels of thiobarbituric acid reactants and a proportional decrease in plasma protein thiols without any appreciable erythrocyte haemolysis. On the basis of preliminary in vitro evidence, these simple laboratory parameters may represent a useful complement in the routine monitoring of biological compliance to the treatment. The clinical experience gained so far confirms the great therapeutic potential of EBOO in patients with severe peripheral arterial disease, coronary disease, cholesterol embolism, severe dyslipidemia, Madelung disease, and sudden deafness of vascular origin. Extensive investigation on oxidative stress biomarkers and clinical trials are under way to validate this new technique further.

Oxidative stress is associated with C-reactive protein in nondiabetic postmenopausal women, independent of obesity and insulin resistance

OBJECTIVE

Oxidative stress is associated with obesity, metabolic syndrome and inflammation, suggesting it could be an early event in the pathology of chronic diseases. We tested the hypothesis that elevated levels of oxidative stress markers are associated with increased C-reactive protein (CRP) and that this is independent of obesity and insulin resistance.

RESEARCH DESIGN AND METHODS

This study was cross-sectional designed and nondiabetic postmenopausal women (n = 1821) with CRP levels ≤10 mg/l was enrolled. The CRP levels were categorized into quartiles from the lowest to the highest concentrations (Q1-Q4). The degree of insulin resistance was determined using the homoeostasis model assessment of insulin resistance (HOMA-IR). We measured oxidative stress using urinary 8-epi-prostaglandin F2α (8-epi-PGF2α) and plasma oxidized low-density lipoprotein (ox-LDL).

RESULTS

After adjustments for age and lifestyle habits, including smoking and drinking, we found higher body mass index (BMI) and HOMA-IR scores in Q2 and Q3 vs Q1. The Q4 BMI and HOMA-IR scores were higher than all other quartiles. The plasma ox-LDL was higher in Q4 than in Q1. Urinary 8-epi-PGF2α was higher in Q3 and Q4 than in Q1 or Q2. Urinary 8-epi-PGF2α positively correlated with CRP (r = 0·235, P < 0·001), whereas no correlation was found between ox-LDL and CRP. Multiple linear regression analyses of BMI and HOMA-IR showed that the association between urinary 8-epi-PGF2α and CRP levels remained significant (P < 0·001).

CONCLUSIONS

Oxidative stress measured by increased concentration of urine 8-epi-PGF2α is strongly associated with CRP levels. This finding was independent of obesity and insulin resistance in nondiabetic postmenopausal women.

Lipidomics of essential fatty acids and oxygenated metabolites

Polyunsaturated fatty acids in mammals may be oxygenated into a myriad of bioactive products through di- and monooxygenases, products that are rapidly degraded to control their action. To evaluate the phenotypes of biological systems regarding this wide family of compounds, a lipidomics approach in function of time and compartments would be relevant. The current review takes into consideration most of the diverse oxygenated metabolites of essential fatty acids at large and their immediate degradation products. Their biological function and life span are considered. Overall, this is a fluxolipidomics approach that is emerging.

Prostaglandin extraction and analysis in Caenorhabditis elegans

Caenorhabditis elegans is emerging as a powerful animal model to study the biology of lipids^1-9. Prostaglandins are an important class of eicosanoids, which are lipid signals derived from polyunsaturated fatty acids (PUFAs)^10-14. These signalling molecules are difficult to study because of their low abundance and reactive nature. The characteristic feature of prostaglandins is a cyclopentane ring structure located within the fatty acid backbone. In mammals, prostaglandins can be formed through cyclooxygenase enzyme-dependent and -independent pathways^10,15. C. elegans synthesizes a wide array of prostaglandins independent of cyclooxygenases^6,16,17. A large class of F-series prostaglandins has been identified, but the study of eicosanoids is at an early stage with ample room for new discoveries. Here we describe a procedure for extracting and analyzing prostaglandins and other eicosanoids. Charged lipids are extracted from mass worm cultures using a liquid-liquid extraction technique and analyzed by liquid chromatography coupled to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The inclusion of deuterated analogs of prostaglandins, such as PGF_{2 α}-d₄ as an internal standard is recommended for quantitative analysis. Multiple reaction monitoring or MRM can be used to quantify and compare specific prostaglandin types between wild-type and mutant animals. Collision-induced decomposition or MS/MS can be used to obtain information on important structural features. Liquid chromatography mass spectrometry (LC-MS) survey scans of a selected mass range, such as m/z 315-360 can be used to evaluate global changes in prostaglandin levels. We provide examples of all three analyses. These methods will provide researchers with a toolset for discovering novel eicosanoids and delineating their metabolic pathways.