Lipid peroxidation products mediate the formation of 8-hydroxydeoxyguanosine in DNA

An environmental approach for the photodegradation of toxic pollutants from wastewater using Pt-Pd nanoparticles: Antioxidant, antibacterial and lipid peroxidation inhibition applications

BACKGROUND

Green synthesis is an effective and friendly method for the environment, especially in recent years has been used in many areas. It finds application opportunities in many fields such as physics, chemistry, electronics, food, and especially health and is the subject of intensive studies in this field.

OBJECTIVES

The synthesized Pt-Pd NPs were aimed to be used as a bio-based photocatalyst under sunlight to prevent wastewater pollution. In addition, it is aimed to use Pt-Pd NPs as biological agents in different applications in the future.

METHODS

In this study, the platinum-palladium nanoparticles were synthesized by the extract of Hibiscus sabdariffa, the characterization of the nanoparticles was carried out by different methods (ultraviolet-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), infrared transform spectroscopy atomic force microscopy (AFM), and ray diffraction (XRD) analysis). And we discussed several different parameters related to human health by obtaining platinum-palladium bimetallic nanoparticles (Pt-Pd NPs) with a green synthesis method. These parameters are antioxidant properties (total phenolic, flavonoid, and DPPH scavenging activity), antibacterial activity, and lipid peroxidation inhibition activity. Gallic acid was used as standard phenolic, and quercetin was used as standard flavonoid reagents. The newly synthesized Hibiscus sabdariffa mediated green synthesized Pt-Pd NPs were compared with gram-positive and gram-negative bacteria, the high antibacterial activity was shown by gram-positive bacteria. The photodegradation of Pt-Pd NPs was carried out against MB dye for 180 min.

RESULTS

TEM results show that the average size of Pt-Pd NPs is around 4.40 nm. The total amount of phenolic compounds contained in 0.2 mg/ml of Pt-Pd NPs was equivalent to 14.962 ± 7.890 μg/ml gallic acid and the total amount of flavonoid component was found to be equal to 28.9986 ± 0.204 μg/ml quercetin. Hibiscus sabdariffa mediated green synthesized Pt-Pd NPs was found to have very effective for lipid peroxidation inhibition activity in the FeCl2-H2O2 system. The maximum DPPH scavenging activity was determined as 97.35% at 200 μg/ml. The photocatalytic activity of Pt-Pd NPs was analysed against Methylene blue (MB) and the maximum degradation percentage was observed to be 83.46% at 180 min.

CONCLUSIONS

The biogenic Pt-Pd NPs showed a high effective photocatalytic and biological activity.

Evaluation of the hydrogen-rich water alleviation potential on mercury toxicity in earthworms using ATR-FTIR and LC-ESI-MS/MS spectroscopy

The toxic effects of mercury in earthworms and the potential alleviation effect of hydrogen-rich water (HRW) using ATR-FTIR and LC-MS analysis methods were investigated. Different concentrations of mercury chloride (H1: 5 µg/mL, H2: 10 µg/mL, H3: 20 µg/mL, H4: 40 µg/mL, and C1: control) and mercury chloride prepared in hydrogen-rich water (H5: 5 µg/mL, H6: 10 µg/mL, H7: 20 µg/mL, H8: 40 µg/mL, and C2: control) were injected into earthworms. The changes and reductions in some bands representing proteins, lipids, and polysaccharides (3280 cm^-1, 2922 cm^-1, 2855 cm^-1, 1170 cm^-1, and 1047 cm^-1) showed that protective effects could occur in groups prepared with hydrogen-rich water. In the FTIR results, it was found that these bands in the H3 group were more affected and decreased by the influence of mercury on earthworms than the H7 group prepared with hydrogen. LC-MS analysis showed that the changes in some ions of the highest dose groups (H4 and H8) were different, and mercury caused oxidative DNA damage in earthworms. When the high-level application groups of mercury, i.e., H4 and H8 were compared with the controls, the ion exchange ([M + H] + ; m/z 283.1) representing the 8-Oxo-dG level in earthworms was higher in the H4 group than the H8 group. This reveals that HRW exhibited the potential ability to alleviate the toxic effects of mercury; however, a longer period of HRW treatment may be necessary to distinguish an obvious effect. The ATR-FTIR spectroscopy provided a rapid and precise method for monitoring the changes in biological tissues caused by a toxic compound at the molecular level.

Model studies of the role of oxygen in the FLASH effect

Current radiotherapy facilities are standardized to deliver dose rates around 0.1-0.4 Gy/s in 2 Gy daily fractions, designed to deliver total accumulated doses to reach the tolerance limit of normal tissues undergoing irradiation. FLASH radiotherapy (FLASH-RT), on the other hand, relies on facilities capable of delivering ultrahigh dose rates in large doses in a single microsecond pulse, or in a few pulses given over a very short time sequence. For example, most studies to date have implemented 4-6 MeV electrons with intra-pulse dose rates in the range 10⁶ -10⁷  Gy/s. The proposed dependence of the FLASH effect on oxygen tension has stimulated several theoretical models based on three different hypotheses: (i) Radiation-induced transient oxygen depletion; (ii) cell-specific differences in the ability to detoxify and/or recover from injury caused by reactive oxygen species; (iii) self-annihilation of radicals by bimolecular recombination. This article focuses on the observations supporting or refuting these models in the frame of the chemical-biological bases of the impact of oxygen on the radiation response of cell free, in vitro and in vivo model systems.

Oxidative stress and DNA damage status in couples undergoing in vitro fertilization treatment

This study examined the status of oxidative stress in 599 couples undertaking in vitro fertilization (IVF) treatment and its association with reproductive hormones, smoking, and outcomes. Oxidative stress biomarkers such as malondialdehyde, 8-hydroxy-2-deoxyguanosine, hydrogen peroxide (H₂O₂), catalase (CAT), and total antioxidant capacity (TAC) were determined in follicular fluid and seminal plasma. Tail moment (TM) was used to evaluate DNA damage in the sperm and granulosa cells. Reproductive hormones in serum and cotinine (COT) in urine, follicular fluid, and seminal plasma samples were determined. Separate multivariate linear regression was used to assess associations between levels of each oxidative stress biomarker and each hormone and smoking parameter (modeled as natural log-transformed). The findings indicate that some oxidative stress and DNA damage biomarkers played a role in disrupting certain reproductive hormones in women and their male partners either by overproducing reactive oxygen species or reducing antioxidant defense capacity. Although women were nonsmokers, COT levels > 50 and 10 µg/L in urine and follicular were observed in 5.7 and 1.7%, respectively. Levels of follicular fluid COT were positively associated with H₂O₂ and TM. We used log-binomial multivariate regression to estimate relative risks for the association between oxidative stress/DNA damage and IVF binary outcomes (fertilization rate > 50%, biochemical pregnancy, clinical pregnancy, and live birth). An increase in the CAT levels of follicular fluid was associated with a 48 and 41% decrease in the risk of poor fertilization rate (≤50%) and unsuccessful live birth, respectively. After the models were adjusted for hormonal factors, the associations remained the same, except that the elevated TAC in follicular fluid became significantly associated with a decrease of 42% in the risk of poor fertilization rate (≤50%). The higher antioxidant activity (CAT and TAC) in follicular fluid might positively impact specific IVF outcomes.

Tanshinone IIA: Pharmacology, total synthesis, and progress in structure-modifications

Tanshinone IIA, a major bioactive constituent of Danshen, a Chinese herbal medicine, has gained extensive exploration owing to its unique structural features and multiple promising biological activities. This review focuses on the pharmacology, total synthesis, and structural modifications of tanshinone IIA. We hope this review will contribute to a better understanding of the progress in the field and provide constructive suggestions for further study of tanshinone IIA.

Dietary chromium modulates glucose homeostasis and induces oxidative stress in Pacific white shrimp (Litopenaeus vannamei)

While chromium (Cr) has been recognized as an essential nutrient for all animals, and dietary supplementation can be beneficial, it can also be toxic. The present study aimed to investigate the contrasting effects of dietary chromium in Pacific white shrimp Litopenaeus vannamei. Five experimental diets were formulated to contain Cr at levels of 0.82 (Cr0.82, unsupplemented diet), 1.01 (Cr1.01), 1.22 (Cu1.22), 1.43 (Cr1.43) and 1.63 (Cr1.63) mg/kg and were fed to shrimp for 8 weeks. Highest weight gain was recorded in shrimp fed the diet containing 1.22 mg/kg Cr. Shrimp fed the diet containing the highest level of Cr (1.63 mg/kg) showed the lowest weight gain and clear signs of oxidative stress and apoptosis as evidenced by higher levels of H₂O₂, malondialdehyde and 8-hydroxydeoxyguanosine, and expression of caspase 2, 3, 5, and lower contents of total and oxidized glutathione, and expression of Cu/Zn sod, cat, gpx, mt, bcl2. Chromium supplementation promoted glycolysis and inhibited gluconeogenesis as shown by increased activities of hexokinase, phosphofructokinase and pyruvate kinase, and reduced activity of phosphoenolpyruvate carboxykinase in shrimp fed the diet containing 1.43 mg/kg Cr. Shrimp fed the diet with 1.63 mg/kg Cr had lowest contents of crustacean hyperglycemic hormone and insulin like peptide in hemolymph. Expression of genes involved in insulin signaling pathway and glycose metabolism including insr, irs1, pik3ca, pdpk1, akt, acc1, gys, glut1, pk, hk were up-regulated, and foxO1, gsk-3β, g6pc, pepck were down-regulated in shrimp fed the diets supplemented with Cr. This study demonstrated that optimum dietary supplementation of Cr had beneficial effects on glucose homeostasis and growth, whereas excess caused oxidative damage and impaired growth. The results contribute to our understanding of the biological functions of chromium in shrimp.

ROS-Induced Hepatotoxicity under Cypermethrin: Involvement of the Crosstalk between Nrf2/Keap1 and NF-κB/iκB-α Pathways Regulated by Proteasome

Cypermethrin (CMN) is a man-made insecticide, and its abuse has led to potential adverse effects, particularly in sensitive populations such as aquatic organisms. The present study was focused on the toxic phenotype and detoxification mechanism in grass carp (Ctenopharyngodon idella) after treatment with waterborne CMN (0.651 μg/L) for 6 weeks in vivo or 6.392 μM for 24 h in vitro. In vivo, we describe the toxic phenotype of the liver of grass carp in terms of pathological changes, serum transaminase levels, oxidative stress indexes, and apoptosis rates. RNA-Seq analysis (2 × 3 cDNA libraries) suggested a compromise of proteasome and oxidative phosphorylation signaling pathways under CMN exposure. Thus, these two pathways were chosen for the in vitro study, which suggested that the CMN intoxication-induced proteasome pathway caused hepatotoxicity in the liver cell line of grass carp (L8824 cells). Moreover, pretreatment with MG132, a proteasome inhibitor, displayed protection against the toxic effects of CMN by enhancing antioxidative and anti-inflammatory capability by directly inhibiting the proteasomal degradation of nuclear factor erythroid-2 related factor (Nrf2) and IκB-α, thus turning on the transcription of downstream genes of Nrf2 and NF-κB, respectively. Taken together, these results suggest proteasome activity as a reason for CMN-induced hepatotoxicity.

High-coverage lipidomics for functional lipid and pathway analyses

Rapid advances in front-end separation approaches and analytical technologies have accelerated the development of lipidomics, particularly in terms of increasing analytical coverage to encompass an expanding repertoire of lipids within a single analytical approach. Developments in lipid pathway analysis, however, have somewhat lingered behind, primarily due to (1) the lack of coherent alignment between lipid identifiers in common databases versus that generated from experiments, owing to the differing structural resolution of lipids at molecular level that is specific to the analytical approaches adopted by various laboratories; (2) the immense complexity of lipid metabolic relationships that may entail head group changes, fatty acyls modifications of various forms (e.g. elongation, desaturation, oxidation), as well as active remodeling that demands a multidimensional, panoramic view to take into account all possibilities in lipid pathway analyses. Herein, we discuss current efforts undertaken to address these challenges, as well as alternative form of "pathway analyses" that may be particularly useful for uncovering functional lipid interactions under different biological contexts. Consolidating lipid pathway analyses will be indispensable in facilitating the transition of lipidomics from its prior role of phenotype validation to a hypothesis-generating tool that uncovers novel molecular targets to drive downstream mechanistic pursuits under biomedical settings.

The Metallome of Lung Cancer and its Potential Use as Biomarker

Carcinogenesis is a very complex process in which metals have been found to be critically involved. In this sense, a disturbed redox status and metal dyshomeostasis take place during the onset and progression of cancer, and it is well-known that trace elements participate in the activation or inhibition of enzymatic reactions and metalloproteins, in which they usually participate as cofactors. Until now, the role of metals in cancer have been studied as an effect, establishing that cancer onset and progression affects the disturbance of the natural chemical form of the essential elements in the metabolism. However, it has also been studied as a cause, giving insights related to the high exposure of metals giving a place to the carcinogenic process. On the other hand, the chemical species of the metal or metallobiomolecule is very important, since it finally affects the biological activity or the toxicological potential of the element and their mobility across different biological compartments. Moreover, the importance of metal homeostasis and metals interactions in biology has also been demonstrated, and the ratios between some elements were found to be different in cancer patients; however, the interplay of elements is rarely reported. This review focuses on the critical role of metals in lung cancer, which is one of the most insidious forms of cancer, with special attention to the analytical approaches and pitfalls to extract metals and their species from tissues and biofluids, determining the ratios of metals, obtaining classification profiles, and finally defining the metallome of lung cancer.

Metals and oxidative potential in urban particulate matter influence systemic inflammatory and neural biomarkers: A controlled exposure study

BACKGROUND

Oxidative stress and inflammation are considered to be important pathways leading to particulate matter (PM)-associated disease. In this exploratory study, we examined the effects of metals and oxidative potential (OP) in urban PM on biomarkers of systemic inflammation, oxidative stress and neural function.

METHODS

Fifty-three healthy non-smoking volunteers (mean age 28 years, twenty-eight females) were exposed to coarse (2.5-10 μm, mean 213 μg/m³), fine (0.15-2.5 μm, 238 μg/m³), and/or ultrafine concentrated ambient PM (<0.3 μm, 136 μg/m³). Exposures lasted 130 min, separated by ≥2 weeks. Metal concentrations and OP (measured by ascorbate and glutathione depletion in synthetic airway fluid) in PM were analyzed. Blood and urine samples were collected pre-exposure, and 1-h and 21-h post exposure for assessment of biomarkers. We used mixed-regression models to analyze associations adjusting for PM size and mass concentration.

RESULTS

Results for metals were expressed as change (%) from daily pre-exposure biomarker levels after exposure to a metal at a level equivalent to the mean concentration. Exposure to various metals (silver, aluminum, barium, copper, iron, potassium, lithium, nickel, tin, and/or vanadium) was significantly associated with increased levels of various blood or urinary biomarkers. For example, the blood inflammatory marker vascular endothelia growth factor (VEGF) increased 5.3% (95% confidence interval: 0.3%, 10.2%) 1-h post exposure to nickel; the traumatic brain injury marker ubiquitin C-terminal hydrolase L1 (UCHL1) increased 11% (1.2%, 21%) and 14% (0.3%, 29%) 1-h and 21-h post exposure to barium, respectively; and the systemic stress marker cortisol increased 1.5% (0%, 2.9%) and 1.5% (0.5%, 2.8%) 1-h and 21-h post exposure to silver, respectively. Urinary DNA oxidation marker 8‑hydroxy‑deoxy‑guanosine increased 14% (6.4%, 21%) 1-h post exposure to copper; urinary neural marker vanillylmandelic acid increased 29% (3%, 54%) 1-h post exposure to aluminum; and urinary cortisol increased 88% (0.9%, 176%) 1-h post exposure to vanadium. Results for OP were expressed as change (%) from daily pre-exposure biomarker levels after exposure to ascorbate-related OP at a level equivalent to the mean concentration, or for exposure to glutathione-related OP at a level above the limit of detection. Exposure to ascorbate- or glutathione-related OP was significantly associated with increased inflammatory and neural biomarkers including interleukin-6, VEGF, UCHL1, and S100 calcium-binding protein B in blood, and malondialdehyde and 8-hydroxy-deoxy-guanosine in urine. For example, UCHL1 increased 9.4% (1.8%, 17%) in blood 21-h post exposure to ascorbate-related OP, while urinary malondialdehyde increased 19% (3.6%, 35%) and 8-hydroxy-deoxy-guanosine increased 24% (2.9%, 48%) 21-h post exposure to ascorbate- and glutathione-related OP, respectively.

CONCLUSION

Our results from this exploratory study suggest that metal constituents and OP in ambient PM may influence biomarker levels associated with systemic inflammation, oxidative stress, perturbations of neural function, and systemic physiological stress.

Risk assessment of environmental exposure to heavy metals in mothers and their respective infants

Exposure to heavy metals can cause renal injury, which has been well documented in occupational exposure. Studies of low exposure in the general population, however, are still scarce, particularly for vulnerable populations such as mothers and young children. This study evaluated exposure to heavy metals, and biomarkers of renal function and oxidative stress in 944 lactating mothers and their infants and investigated the role of the interaction between heavy metals and oxidative stress in altering renal function. Mother and infant urine samples were analyzed to measure mercury (Hg), cadmium (Cd), and lead (Pb) concentrations for determining body-burden exposure; N-acetyl-β-d-glucosaminidase (NAG), α₁-microglobulin (α₁-MG), albumin (ALB), and creatinine (Cr) concentrations for determining early renal injury; and 8-hydroxy-2-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) concentrations for determining oxidative stress. The median concentrclearlyations in mothers presented as μg/g Cr (infants as μg/l) for Hg, Cd, and Pb were 0.695 (0.716), 0.322 (0.343), and 3.97 (5.306) respectively. The mothers and their infants had clearly been exposed to heavy metals and had levels higher than the reference values reported for the general populations of USA, Germany, and Canada. Multiple regression analyses clearly demonstrated associations between urinary heavy metals in quartiles and several renal and oxidative biomarkers in mothers and to a lesser extent their infants. ß coefficients for urinary excretions of MDA, 8-OHdG, ALB, α₁-MG, NAG, and Cr in mothers were high in the highest quartile of Hg (1.183-51.29μg/g Cr or 1.732-106.95μg/l), Cd (0.565-765.776μg/g Cr or 0.785-1347.0μg/l), and Pb (6.606-83.937μg/g Cr or 9.459-80.826μg/l), except Pb was not associated with ALB. Infants in the highest Pb quartile (9.293-263.098μg/l) had the highest ß coefficients of urinary excretion of MDA, 8-OHdG, ALB, NAG, and Cr. Significant increasing trend in biomarkers across the quartiles of the three metals was seen in both mothers and infants (p_trend <0.001). A receiver operating characteristic analysis supported the predictive abilities of the four renal biomarkers in discriminating between low versus high metal quartiles. The interaction between heavy metals and oxidative stress contributed to the high excretions of renal biomarkers, but the mechanism remains unclear. These findings add to the limited evidence that low exposure to heavy metals in the general population is associated with alterations in renal function that could eventually progress to renal damage if exposure continues and that children are more susceptible due to the immaturity of their body organs.

Regular exercise participation improves genomic stability in diabetic patients: an exploratory study to analyse telomere length and DNA damage

Physical activity has been demonstrated to be effective in the prevention and treatment of different chronic conditions, including type 2 diabetes (T2D). In particular, several studies highlighted how the beneficial effects of physical activity may be related to the stability of the DNA molecule, such as longer telomeric ends. Here we analyze the effect of exercise training on telomere length, spontaneous and H₂O₂-induced DNA damage, as well as the apoptosis level in leukocytes from untrained or trained T2D patients vs. age-matched control subjects (CS) (57–66 years). Moreover, expression analysis of selected genes belonging to DNA repair systems, cell cycle control, antioxidant and defence systems was performed. Subjects that participated in a regular exercise program showed a longer telomere sequence than untrained counterparts. Moreover, ex vivo treatment of leukocytes with H₂O₂ highlighted that: (1) oxidative DNA damage induced similar telomere attrition in all groups; (2) in T2D subjects, physical activity seemed to prevent a significant increase of genomic oxidative DNA damage induced by chronic exposure to pro-oxidant stimulus, and (3) decreased the sensitivity of leukocytes to apoptosis. Finally, the gene expression analysis in T2D subjects suggested an adaptive response to prolonged exercise training that improved the response of specific genes.

Influence of exposure to coarse, fine and ultrafine urban particulate matter and their biological constituents on neural biomarkers in a randomized controlled crossover study

BACKGROUND

Epidemiological studies have reported associations between air pollution and neuro-psychological conditions. Biological mechanisms behind these findings are still not clear.

OBJECTIVES

We examined changes in blood and urinary neural biomarkers following exposure to concentrated ambient coarse, fine and ultrafine particles.

METHODS

Fifty healthy non-smoking volunteers, mean age 28years, were exposed to coarse (2.5-10μm, mean 213μg/m³) and fine (0.15-2.5μm, mean 238μg/m³) concentrated ambient particles (CAPs), and filtered ambient and/or medical air. Twenty-five participants were exposed to ultrafine CAP (mean size 59.6nm, range 47.0-69.8nm), mean (136μg/m³) and filtered medical air. Exposures lasted 130min, separated by ≥2weeks, and the biological constituents endotoxin and β-1,3-d-glucan of each particle size fraction were measured. Blood and urine samples were collected pre-exposure, and 1-hour and 21-hour post-exposure to determine neural biomarker levels. Mixed-model regressions assessed associations between exposures and changes in biomarker levels.

RESULTS

Results were expressed as percent change from daily pre-exposure biomarker levels. Exposure to coarse CAP was significantly associated with increased urinary levels of the stress-related biomarkers vanillylmandelic acid (VMA) and cortisol when compared with exposure to filtered medical air [20% (95% confidence interval: 1.0%, 38%) and 64% (0.2%, 127%), respectively] 21hours post-exposure. However exposure to coarse CAP was significantly associated with decreases in blood cortisol [-26.0% (-42.4%, -9.6%) and -22.4% (-43.7%, -1.1%) at 1h and 21h post-exposure, respectively]. Biological molecules present in coarse CAP were significantly associated with blood biomarkers indicative of blood brain barrier integrity. Endotoxin content was significantly associated with increased blood ubiquitin C-terminal hydrolase L1 [UCHL1, 11% (5.3%, 16%) per ln(ng/m³+1)] 1-hour post-exposure, while β-1,3-d-glucan was significantly associated with increased blood S100B [6.3% (3.2%, 9.4%) per ln(ng/m³+1)], as well as UCHL1 [3.1% (0.4%, 5.9%) per ln(ng/m³+1)], one-hour post-exposure. Fine CAP was marginally associated with increased blood UCHL1 when compared with exposure to filtered medical air [17.7% (-1.7%, 37.2%), p=0.07] 21hours post-exposure. Ultrafine CAP was not significantly associated with changes in any blood and urinary neural biomarkers examined.

CONCLUSION

Ambient coarse particulate matter and its biological constituents may influence neural biomarker levels that reflect perturbations of blood-brain barrier integrity and systemic stress response.

Alterations in biochemical markers due to mercury (Hg) exposure and its influence on infant's neurodevelopment

This study examined the role of oxidative stress due to mercury (Hg) exposure on infant's neurodevelopmental performance. A total of 944 healthy Saudi mothers and their respective infants (aged 3-12 months) were recruited from 57 Primary Health Care Centers in Riyadh City. Total mercury (Hg) was measured in mothers and infants urine and hair samples, as well as mother's blood and breast milk. Methylmercury (MeHg) was determined in the mothers and infants' hair and mother's blood. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), malondialdehyde (MDA), and porphyrins were used to assess oxidative stress. The infant's neurodevelopment was evaluated using Denver Developmental Screening Test II (DDST-II) and Parents' Evaluation of Developmental Status. The median total Hg levels in mother's urine, infant's urine, mother's hair, infant's hair, and mother's blood and breast milk were 0.995μg/l, 0.716μg/l, 0.118μg/g dw, 0.101μg/g dw, 0.635μg/l, and 0.884μg/l respectively. The median MeHg levels in mother's hair, infant's hair, and mother's blood were 0.132μg/g dw, 0.091μg/g dw, and 2.341μg/l respectively. A significant interrelationship between mothers and infants Hg measures in various matrices was noted. This suggests that mother's exposure to different forms of Hg (total and/or MeHg) from various sources contributed significantly to the metal body burden of their respective infants. Even though Hg exposure was low, it induced high oxidative stress in mothers and infants. The influence of multiplicative interaction terms between Hg measures and oxidative stress biomarkers was tested using multiple regression analysis. Significant interactions between the urinary Hg levels in mothers and infants and oxidative stress biomarkers (8-OHdG and MDA) were noted. The MeHg levels in mother-infant hair revealed similar interaction patterns. The p-values for both were below 0.001. These observations suggest that the exposure of our infants to Hg via mothers either during pregnancy and/or neonatal life, promoted oxidative stress that might have played a role in infant neurodevelopmental delays that we reported previously. The results confirmed that the interaction between infant's MeHg in hair and 8-OHdG and MDA levels was significantly associated with a delay in DDST-II performance (ß=-0.188, p=0.028). This finding provides an insight into the potential consequences of Hg-induced oxidative stress to infant's cognitive neurodevelopment for the first time. This observation still needs future studies to be validated. Given the low MeHg levels in our population, these findings are of particular importance.

Lipid peroxides as endogenous oxidants forming 8-oxo-guanosine and lipid-soluble antioxidants as suppressing agents

The oxidation of guanosine to 8-oxo-2'-deoxyguanosine (8-oxo-dG) in DNA is closely associated with induction of various diseases, but the endogenous oxidant species involved remains unclear. Hydrogen peroxides (H2O2) have been considered to be the oxidant, while lipid peroxides are another possible oxidant because generated easily in bio-membranes surrounding DNA. The oxidant potency was compared between lipid peroxides and H2O2. Linoleic acid hydroperoxides (LOOH) formed 8-oxo-dG at a higher level than H2O2 in guanosine or double-stranded DNA. In the presence of a physiological concentration of Fe(2+) to produce hydroxyl radicals, LOOH was also a stronger oxidant. In a lipid micelle, LOOH markedly produced 8-oxo-dG at a concentration one-tenth of that of H2O2. Upon adding to rat hepatic mitochondria, phosphatidylcholine hydroperoxides produced 8-oxo-dG abundantly. Employing HepG2 cells after pretreated with glutathione peroxidase inhibitor, LOOH formed 8-oxo-dG more abundantly than H2O2. Then, antioxidants to suppress the 8-oxo-dG formation were examined, when the nuclei of pre-incubated HepG2 with antioxidants were exposed to LOOH. Water-soluble ascorbic acid, trolox, and N-acetyl cysteine showed no or weak antioxidant potency, while lipid-soluble 2,6-dipalmitoyl ascorbic acid, α-tocopherol, and lipid-soluble phytochemicals exhibited stronger potency. The present study shows preferential formation of 8-oxo-dG upon LOOH and the inhibition by lipid-soluble antioxidants.

Effects of a dietary intervention with conjugated linoleic acid on immunological and metabolic parameters in children and adolescents with allergic asthma--a placebo-controlled pilot trial

Background

Circumstantial evidence suggests that conjugated linoleic acid (CLA) beneficially modulates immune function in allergic subjects. C9,t11-CLA, naturally occurring in ruminant fats, is suggested to be the effective isomer. In contrast, for the t10,c12-CLA isomer, which is naturally found only in traces but usually constitutes a relevant part in commercial CLA mixtures, adverse effects have been reported. Aim of this study was to assess putative immunomodulatory effects of highly enriched c9,t11-CLA in allergic subjects. To our best knowledge, our study is the first in that a CLA preparation was used for such purpose which was free of t10,c12-CLA.

Design

Twenty-nine asthmatic children and adolescents (age 6–18 y) with diagnosed allergic sensitization against grass pollen, house dust mite, or cat hair/epithelia consumed daily a portion of yoghurt containing either 3 g CLA (75 % c9,t11-CLA, 87 % purity) or placebo (safflower oil) over a period of 12 weeks. At study start and end, lung function parameters, specific IgE, in vitro allergen-induced cytokine production in peripheral blood mononuclear cells (PBMC), plasma ECP, urinary 8-oxodG as marker of oxidation, fatty acid profiles of erythrocytes, and routine haematological parameters were determined. Prior to blood samplings, 3-days dietary records were requested. Throughout the study, the participants documented daily their peak expiratory flow and kept protocol about their allergy symptoms and usage of demand medication.

Results

In contrast to the CLA group, PBMC-produced IFN-γ and IL-4 increased significantly and by trend, respectively, in the placebo group. Moreover, plasma ECP tended to increase in the placebo group. In the pollen subgroup, FEV1 improved upon both CLA and placebo oil supplementation. In both intervention groups, the n-6/n-3 PUFA ratio in red blood cells decreased, mainly due to an increase in n-3 PUFA. Moreover, 8-oxodG excretion increased in both groups. No changes occurred regarding specific IgE concentrations, allergy symptoms, and volume parameters.

Conclusion

Our results indicate that CLA modestly dampens the inflammatory response on the cellular level. A clinically relevant amelioration of the symptoms could not be proved in atopic manifest patients.

Trial registration

NCT01026506.

The Role of the Reactive Oxygen Species and Oxidative Stress in the Pathomechanism of the Age-Related Ocular Diseases and Other Pathologies of the Anterior and Posterior Eye Segments in Adults

The reactive oxygen species (ROS) form under normal physiological conditions and may have both beneficial and harmful role. We search the literature and current knowledge in the aspect of ROS participation in the pathogenesis of anterior and posterior eye segment diseases in adults. ROS take part in the pathogenesis of keratoconus, Fuchs endothelial corneal dystrophy, and granular corneal dystrophy type 2, stimulating apoptosis of corneal cells. ROS play a role in the pathogenesis of glaucoma stimulating apoptotic and inflammatory pathways on the level of the trabecular meshwork and promoting retinal ganglion cells apoptosis and glial dysfunction in the posterior eye segment. ROS play a role in the pathogenesis of Leber's hereditary optic neuropathy and traumatic optic neuropathy. ROS induce apoptosis of human lens epithelial cells. ROS promote apoptosis of vascular and neuronal cells and stimulate inflammation and pathological angiogenesis in the course of diabetic retinopathy. ROS are associated with the pathophysiological parainflammation and autophagy process in the course of the age-related macular degeneration.

Effects of ambient coarse, fine, and ultrafine particles and their biological constituents on systemic biomarkers: a controlled human exposure study

BACKGROUND

Ambient coarse, fine, and ultrafine particles have been associated with mortality and morbidity. Few studies have compared how various particle size fractions affect systemic biomarkers.

OBJECTIVES

We examined changes of blood and urinary biomarkers following exposures to three particle sizes.

METHODS

Fifty healthy nonsmoking volunteers, mean age of 28 years, were exposed to coarse (2.5-10 μm; mean, 213 μg/m3) and fine (0.15-2.5 μm; mean, 238 μg/m3) concentrated ambient particles (CAPs), and filtered ambient and/or medical air. Twenty-five participants were exposed to ultrafine CAP (< 0.3 μm; mean, 136 μg/m3) and filtered medical air. Exposures lasted 130 min, separated by ≥ 2 weeks. Blood/urine samples were collected preexposure and 1 hr and 21 hr postexposure to determine blood interleukin-6 and C-reactive protein (inflammation), endothelin-1 and vascular endothelial growth factor (VEGF; vascular mediators), and malondialdehyde (lipid peroxidation); as well as urinary VEGF, 8-hydroxy-deoxy-guanosine (DNA oxidation), and malondialdehyde. Mixed-model regressions assessed pre- and postexposure differences.

RESULTS

One hour postexposure, for every 100-μg/m3 increase, coarse CAP was associated with increased blood VEGF (2.41 pg/mL; 95% CI: 0.41, 4.40) in models adjusted for O3, fine CAP with increased urinary malondialdehyde in single- (0.31 nmol/mg creatinine; 95% CI: 0.02, 0.60) and two-pollutant models, and ultrafine CAP with increased urinary 8-hydroxydeoxyguanosine in single- (0.69 ng/mg creatinine; 95% CI: 0.09, 1.29) and two-pollutant models, lasting < 21 hr. Endotoxin was significantly associated with biomarker changes similar to those found with CAPs.

CONCLUSIONS

Ambient particles with various sizes/constituents may influence systemic biomarkers differently. Endotoxin in ambient particles may contribute to vascular mediator changes and oxidative stress.

Attenuated SAG expression exacerbates 4-hydroxy-2-nonenal-induced apoptosis and hypertrophy of H9c2 cardiomyocytes

Oxidative stress, associated with the accumulation of reactive oxygen species (ROS), results in numerous and detrimental effects on the myocardium such as the induction of apoptotic cell death, hypertrophy, fibrosis, dysfunction, and dilatation. The product of sensitive to apoptosis gene (SAG) is a RING finger protein that has been shown to have a protective effect against apoptosis induced by oxidative stress in various cell types. The major reactive aldehydic product of lipid peroxidation, 4-hydroxy-2-nonenal (HNE), is believed to be largely responsible for cytopathological effects observed during oxidative stress. In the present study, we showed that the transfection of H9c2 clonal myoblastic cells with small interfering RNA (siRNA) specific for SAG markedly attenuated SAG expression and exacerbates HNE-induced apoptosis and hypertrophy. The knockdown of SAG expression resulted in the modulation of cellular redox status, mitochondrial function, and cellular oxidative damage. Taken together, our results showed that the suppression of SAG expression by siRNA enhanced HNE-induced apoptosis and hypertrophy of cultured cardiomyocytes via the disruption of the cellular redox balance. Given the importance of the SAG protein in the regulation of the redox status of cardiomyocytes, we conclude that this protein may be a potential new target in the development of therapeutic agents for the prevention of cardiovascular diseases.

Mercury (Hg) exposure in breast-fed infants and their mothers and the evidence of oxidative stress

The objective of this work was to assess exposure to mercury (Hg) and its induction of oxidative stress in 155 healthy lactating Saudi mothers and their infants. Samples of breast milk and blood were collected from the mothers, while urine was taken from both infants and mothers. Both urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) were measured in mothers and infants as biomarkers of oxidative stress. The mean concentration of Hg in breast milk was 1.19 μg/L (range 0.012-6.44 μg/L) with only one mother having Hg >4 μg/L, the upper limit established by the US Agency for Toxic Substance and Disease Registry. However, 57.4 % had Hg ≥1 μg/L, the background level for Hg in human milk. The mean urinary Hg corrected for creatinine (Hg-C) in mothers and infants was 1.47 and 7.90 μg/g creatinine, respectively, with a significant correlation between the two (p < 0.001). Urinary Hg levels over 5 μg/g creatinine (the background level in an unexposed population) were found in 3.3 % of mothers and 50.1 % of infants. None of the mothers had total blood Hg above the US Environmental Protection Agency's maximum reference dose of 5.8 μg/L. No correlation was noted between urinary Hg in infants and Hg in breast milk (p > 0.05). Hg in breast milk, though, was associated with Hg in blood (p < 0.001), suggesting the efficient transfer of Hg from blood to milk. Hg in the breast milk of mothers and in the urine of infants affected the excretion of urinary MDA and 8-OHdG, respectively, in a dose-related manner. These findings reveal for the first time lactational exposure to Hg-induced oxidative stress in breast-fed infants, which may play a role in pathogenesis, particularly during neurodevelopment. This will also contribute to the debate over the benefits of breast milk versus the adverse effects of exposure to pollutants. Nevertheless, breastfeeding should not be discouraged, but efforts should be made to identify and eliminate the source of Hg exposure in the population.

Environmental light and endogenous antioxidants as the main determinants of non-cancer ocular diseases

The human eye is constantly exposed to sunlight and artificial lighting. Exogenous sources of reactive oxygen species (ROS) such as UV light, visible light, ionizing radiation, chemotherapeutics, and environmental toxins contribute to oxidative damage in ocular tissues. Long-term exposure to these insults places the aging eye at considerable risk for pathological consequences of oxidative stress. Furthermore, in eye tissues, mitochondria are an important endogenous source of ROS. Over time, all ocular structures, from the tear film to the retina, undergo oxidative stress, and therefore, the antioxidant defenses of each tissue assume the role of a safeguard against degenerative ocular pathologies. The ocular surface and cornea protect the other ocular tissues and are significantly exposed to oxidative stress of environmental origin. Overwhelming of antioxidant defenses in these tissues clinically manifests as pathologies including pterygium, corneal dystrophies, and endothelial Fuch's dystrophy. The crystalline lens is highly susceptible to oxidative damage in aging because its cells and their intracellular proteins are not turned over or replaced, thus providing the basis for cataractogenesis. The trabecular meshwork, which is the anterior chamber tissue devoted to aqueous humor drainage, has a particular susceptibility to mitochondrial oxidative injury that affects its endothelium and leads to an intraocular pressure increase that marks the beginning of glaucoma. Photo-oxidative stress can cause acute or chronic retinal damage. The pathogenesis of age-related macular degeneration involves oxidative stress and death of the retinal pigment epithelium followed by death of the overlying photoreceptors. Accordingly, converging evidence indicates that mutagenic mechanisms of environmental and endogenous sources play a fundamental pathogenic role in degenerative eye diseases.

Prevention of rat breast cancer by genistin and selenium

Breast cancer is the second leading cause of cancer death among women and the third most common cancer. In this study, we investigated the chemoprevention efficacy of each of soy genistin, selenium or a combination of them against breast cancer. Seventy-five female rats were divided into five groups : control group (I); 7,12-dimethylbenz(a)anthracene (DMBA) group (II); DMBA treated with genistin group (III); DMBA treated with selenium group (IV); and DMBA treated with genistin combined with selenium group (V). The treatments were daily administered for 3 months. There were a significant decrease in body weight and serum total antioxidant, while a significant elevation in serum total sialic acid, carcinoembryonic antigen, prolactin, estradiol, nitric oxide, and malondialdhyde of DMBA injected rats compared with control group. Administration of genistin and selenium was associated with decreasing levels of tumorigenicity, endocrine derangement, and oxidative stress. Formation of breast carcinoma in DMBA-induced rats and abnormal changes were ameliorated in the rats treated with genistin/selenium or genistin alone. Supplementation of genistin alone or with selenium provided antioxidant defense with high-potential chemopreventive activity against DMBA-induced mammary tumors more than selenium alone.

Poly(ADP-ribose) polymerase-1 is a key mediator of cisplatin-induced kidney inflammation and injury

Cisplatin is a commonly used chemotherapeutic drug, the clinical use of which is limited by the development of dose-dependent nephrotoxicity. Enhanced inflammatory response, oxidative stress, and cell death have been implicated in the development of cisplatin-induced nephropathy; however, the precise mechanisms are elusive. Overactivation of the nuclear enzyme poly(ADP-ribose) polymerase-1 (PARP-1) by oxidative DNA damage under various pathological conditions promotes cell death and up-regulation of key proinflammatory pathways. In this study, using a well-established model of nephropathy, we have explored the role of PARP-1 in cisplatin-induced kidney injury. Genetic deletion or pharmacological inhibition of PARP-1 markedly attenuated the cisplatin-induced histopathological damage, impaired renal function (elevated serum BUN and creatinine levels), and enhanced inflammatory response (leukocyte infiltration; TNF-α, IL-1β, F4/80, adhesion molecules ICAM-1/VCAM-1 expression) and consequent oxidative/nitrative stress (4-HNE, 8-OHdG, and nitrotyrosine content; NOX2/NOX4 expression). PARP inhibition also facilitated the cisplatin-induced death of cancer cells. Thus, PARP activation plays an important role in cisplatin-induced kidney injury, and its pharmacological inhibition may represent a promising approach to preventing the cisplatin-induced nephropathy. This is particularly exciting because several PARP inhibitors alone or in combination with DNA-damaging anticancer agents show considerable promise in clinical trials for treatment of various malignancies (e.g., triple-negative breast cancer).

Mitochondria induce oxidative stress, generation of reactive oxygen species and redox state unbalance of the eye lens leading to human cataract formation: disruption of redox lens organization by phospholipid hydroperoxides as a common basis for cataract disease

The aging eye appears to be at considerable risk from oxidative stress. Lipid peroxidation (LPO) is one of the mechanisms of cataractogenesis, initiated by enhanced promotion of oxygen free radicals in the eye fluids and tissues and impaired enzymatic and non-enzymatic antioxidant defenses of the crystalline lens. The present study proposes that mitochondria are one of the major sources of reactive oxygen species (ROS) in mammalian and human lens epithelial cells and that therapies that protect mitochondria in lens epithelial cells from damage and reduce damaging ROS generation may potentially ameliorate the effects of free radical-induced oxidation that occur in aging ocular tissues and in human cataract diseases. It has been found that rather than complete removal of oxidants by the high levels of protective enzyme activities such as superoxide dismutase (SOD), catalase, lipid peroxidases in transparent lenses, the lens conversely, possess a balance between peroxidants and antioxidants in a way that normal lens tends to generate oxidants diffusing from lenticular tissues, shifting the redox status of the lens to become more oxidizing during both morphogenesis and aging. Release of the oxidants (O(2)(-)·, H(2)O(2) , OH·, and lipid hydroperoxides) by the intact lenses in the absence of respiratory inhibitors indicates that these metabolites are normal physiological products inversely related to the lens life-span potential (maturity of cataract) generated through the metal-ion catalyzed redox-coupled pro-oxidant activation of the lens reductants (ascorbic acid, glutathione). The membrane-bound phospholipid (PL) hydroperoxides escape detoxification by the lens enzymatic reduction. The lens cells containing these species would be vulnerable to peroxidative attack which trigger the PL hydroperoxide-dependent chain propagation of LPO and other damages in membrane (lipid and protein alterations). The increased concentrations of primary LPO products (diene conjugates, lipid hydroperoxides) and end fluorescent LPO products were detected in the lipid moiety of the aqueous humor samples obtained from patients with cataract as compared to normal donors. Since LPO is clinically important in many of the pathological effects and aging, new therapeutic modalities, such as patented N-acetylcarnosine prodrug lubricant eye drops, should treat the incessant infliction of damage to the lens cells and biomolecules by reactive lipid peroxides and oxygen species and "refashion" the affected lens membranes in the lack of important metabolic detoxification of PL peroxides. Combined in ophthalmic formulations with N-acetylcarnosine, mitochondria-targeted antioxidants are promising to become investigated as a potential tool for treating a number of ROS-related ocular diseases, including human cataracts.

Study on the changes of urinary 8-hydroxydeoxyguanosine levels and burden of heavy metal around e-waste dismantling site

To examine the relations between the burden of blood copper (B-Cu), blood ferrous (B-Fe), and the oxidative stress in people around electronic waste (e-waste) recycling sites, this study measured and analyzed the level of urinary 8-Hydroxy-2'-deoxyguanosine (8-OHDG) of these people. Exposed groups, consisted of female groups (directly exposed group n=100, indirectly exposed group n=54) and male groups (directly exposed group n=98, indirectly exposed group n=34), were chosen from e-waste recycling sites. Control group (female n=59, male=32) was selected from a green plantation. Questionnaire surveys for risk factors were also performed. Results indicated the male directly exposed group (lg8-OHDG nmol/mol creatinine, mean±SD, 3.55±0.49) showed a lower 8-OHDG level than the male control group (lg8-OHDG nmol/mol creatinine, mean±SD, 3.89±0.29) (p<0.01), Meanwhile, an elevated B-Fe in male directly exposed group (lgB-Fe ug/L 3.11±0.25) were observed compared with the male control group (lgB-Fe ug/L 2.83±0.22) (p<0.01). The levels of urinary 8-OHDG were negatively associated with blood ferrous, as confirmed by linear regression model (unstandardized regression coefficient, beta=-0.215, p<0.05). The present study suggests that the exposure to e-waste might cause the elevation of B-Fe and result in the changes of urinary 8-OHDG levels.

Effects of epigallocatechin gallate, L-ascorbic acid, alpha-tocopherol, and dihydrolipoic acid on the formation of deoxyguanosine adducts derived from lipid peroxidation

Oxidation of polyunsaturated fatty acids (PUFAs) releases alpha,beta-unsaturated aldehydes that modify deoxyguanosine (dG) to form cyclic 1,N(2)-propanodeoxyguanosine adducts. One of the major adducts detected in vivo is acrolein (Acr)-derived 1,N(2)-propanodeoxyguanosine (Acr-dG). We used a chemical model system to examine the effects of 4 antioxidants known to inhibit fatty acid oxidation on the formation of Acr-dG and 8-oxodeoxyguaonsine (8-oxodG) from the PUFA docosahexaenoic acid (DHA) under oxidative conditions. We found that epigallocatechin gallate (EGCG) and dihydrolipoic acid (DHLA) inhibit both Acr-dG and 8-oxodG formation. In contrast, ascorbic acid and alpha-tocopherol actually increase Acr-dG at high concentrations and do not show a concentration-dependant inhibition of 8-oxodG. We also studied their effects on blocking Acr-dG formation directly from Acr. EGCG and DHLA can both effectively block Acr-dG formation, but ascorbic acid and alpha-tocopherol show weak or little effect. These results highlight the complexity of antioxidant mechanisms and also reveal that EGCG and DHLA are effective at suppressing lipid peroxidation-induced Acr-dG and 8-oxodG formation as well as blocking the reaction of dG with Acr.

Silencing of cytosolic NADP(+)-dependent isocitrate dehydrogenase by small interfering RNA enhances the sensitivity of HeLa cells toward staurosporine

Staurosporine induces the production of reactive oxygen species, which play an important causative role in apoptotic cell death. Recently, it was demonstrated that the control of cellular redox balance and the defense against oxidative damage is one of the primary functions of cytosolic NADP(+)-dependent isocitrate dehydrogenase (IDPc) by supplying NADPH for antioxidant systems. The present report shows that silencing of IDPc expression in HeLa cells greatly enhances apoptosis induced by staurosporine. Transfection of HeLa cells with an IDPc small interfering RNA (siRNA) markedly decreased activity of IDPc, enhancing the susceptibility of staurosporine-induced apoptosis reflected by DNA fragmentation, cellular redox status and the modulation of apoptotic marker proteins. These results indicate that IDPc may play an important role in regulating the apoptosis induced by staurosporine and the sensitizing effect of IDPc siRNA on the apoptotic cell death of HeLa cells offers the possibility of developing a modifier of cancer chemotherapy.

Antioxidant enzyme inhibitors enhance singlet oxygen-induced cell death in HL-60 cells

Singlet oxygen is a highly reactive form of molecular oxygen that may harm living systems by oxidizing critical cellular macromolecules and it also promotes deleterious processes such as cell death. The protective role of antioxidant enzymes against singlet oxygen-induced oxidative damage in HL-60 cells was investigated in control and cells pre-treated with diethyldithiocarbamic acid, aminotriazole and oxlalomalate, specific inhibitors of superoxide dismutase, catalase and NADP+-dependent isocitrate dehydrogenase, respectively. Upon exposure to rose bengal (20 microM)/light (15 min), which generates singlet oxygen, to HL-60 cells, the viability was lower and the lipid peroxidation and oxidative DNA damage were higher in inhibitor-treated cells as compared to control cells. We also observed the significant increase in the endogenous production of reactive oxygen species as well as the significant decrease in the intracellular GSH level in inhibitor-treated HL-60 cells exposed to singlet oxygen. Upon exposure to rose bengal (3 microM)/light (15 min), which induced apoptotic cell death, a clear inverse relationship was observed between the control and inhibitor-treated HL-60 cells in their susceptibility to apoptosis. These results suggest that antioxidant enzymes play an important role in cellular defense against singlet oxygen-induced cell death including necrosis and apoptosis.

Lipid peroxidation in early type 1 diabetes mellitus is unassociated with oxidative damage to DNA

Oxidative stress damages DNA in experimental diabetes, and in vitro studies have suggested that it is linked to lipid peroxidation. The objective of the study was to determine whether lipid peroxidation, as assessed with malondialdehyde excretion in recent-onset type 1 diabetes mellitus, is associated with oxidative damage to DNA, as assessed from 8-hydroxydeoxyguanosine excretion. A 3-year longitudinal study of recent-onset type 1 diabetes mellitus was performed. Age- and sex-matched control subjects were studied once. Patients were studied as inpatients at West Virginia University Hospitals. Thirty-seven patients with recent-onset (2-22 months) type 1 diabetes mellitus (male, 10; female, 27) were enrolled in a longitudinal study of oxidative stress. The mean age of the patients was 20 years. None of the patients had hyperlipidemia or were treated with lipid-lowering drugs. Only 1 patient had hypertension and was being treated with beta-adrenergic blocking therapy. Thirty-six patients completed the study; one withdrew after the second evaluation. Lipid peroxidation was assessed by measuring malondialdehyde excretion. Oxidative damage to DNA was assessed from 8-hydroxydeoxyguanosine excretion. Malondialdehyde excretion was increased in the diabetic patients at the first evaluation (2.43 +/- 0.31 micromol/g creatinine), second evaluation (2.34 +/- 0.24), and third evaluation (1.93 +/- 0.15) compared with control subjects (1.51 +/- 0.11) (P < .005). 8-Hydroxydeoxyguanosine excretion, however, was not increased in the diabetic patients. There was no correlation between malondialdehyde and 8-hydroxydeoxyguanosine excretion. We confirmed the presence of oxidative stress in early diabetes as assessed from malondialdehyde excretion. We were unable, however, to confirm oxidative damage to DNA in this cohort of patients; and there was no evidence of a correlation between lipid peroxidation and DNA damage.

The use of ebselen for radioprotection in cultured cells and mice

Ionizing radiation induces the production of reactive oxygen species (ROS), which play an important causative role in cell death. Therefore, compounds that control the level of ROS may confer radioprotective effects. Ebselen, a seleno-organic compound, has been shown to protect against cell injury caused by ROS. The objective of this study was to examine the effects of ebselen on radiation-dependent toxicity. We investigated the protective role of ebselen against ionizing radiation in U937 cells and mice. Upon exposure to 20 Gy of gamma-irradiation, there was a distinct difference between untreated cells and the cells pretreated with 5 microM ebselen for 2 h with respect to viability, cellular redox status, and oxidative damage to cells. When cells were exposed to 2 Gy of gamma-irradiation, there was a distinct difference between the untreated cells and the cells pretreated with ebselen with respect to apoptotic features and mitochondrial function. Ebselen administration for 14 days at a daily dosage of 10 mg/kg provided substantial protection against killing and oxidative damage to mice exposed to whole-body irradiation. These data indicate that ebselen may have great potential as a new class of in vivo, non-sulfur-containing radiation protector.

Lipid peroxidation up-regulates BACE1 expression in vivo: a possible early event of amyloidogenesis in Alzheimer's disease

Increased lipid peroxidation is shown to be an early event of Alzheimer's disease (AD). However, it is not clear whether and how increased lipid peroxidation might lead to amyloidogenesis, a hallmark of AD. Glutathione peroxidase 4 (Gpx4) is an essential antioxidant defense enzyme that protects an organism against lipid peroxidation. Gpx4+/- mice show increased lipid peroxidation in brain, as evidenced by their elevated levels of 4-hydroxy-2-nonenal. To understand the role of lipid peroxidation in amyloidogenesis, we studied secretase activities in Gpx4+/- mice as a function of age. Both young (6 months) and middle-aged (17-20 months) Gpx4+/- mice had higher levels of beta-secretase activity than their age-matched wildtype controls, and the increased beta-secretase activity in Gpx4+/- mice was a result of up-regulation of beta-site amyloid precursor protein cleavage enzyme 1 (BACE1) expression at the protein level. The high level of BACE1 protein led to increased endogenous beta-amyloid (Abeta)(1-40) in middle-aged Gpx4+/- mice. We further studied amyloidogenesis in APPGpx4+/- mice. Our data indicate that APPGpx4+/- mice had significantly increased amyloid plaque burdens and increased Abeta(1-40) and Abeta(1-42) levels compared with APPGpx4+/+ mice. Therefore, our results indicate that increased lipid peroxidation leads to increased amyloidogenesis through up-regulation of BACE1 expression in vivo, a mechanism that may be important in pathogenesis of AD at early stages.

Regulation of heat shock-induced apoptosis by sensitive to apoptosis gene protein

Heat shock may increase oxidative stress due to increased production of reactive oxygen species and/or the promotion of cellular oxidation events. Sensitive to apoptosis gene (SAG) protein, a novel zinc RING finger protein that protects mammalian cells from apoptosis by redox reagents, is a metal chelator and a potential reactive oxygen species scavenger, but its antioxidant properties have not been completely defined. In this report, we demonstrate that modulation of SAG expression in U937 cells regulates heat shock-induced apoptosis. When we examined the protective role of SAG against heat shock-induced apoptosis with U937 cells transfected with the cDNA for SAG, a clear inverse relationship was observed between the amount of SAG expressed in target cells and their susceptibility to apoptosis. We also observed a significant decrease in the endogenous production of reactive oxygen species and oxidative DNA damage in SAG-overexpressed cells compared to control cells on exposure to heat shock. In addition, transfection of PC3 cells with SAG small interfering RNA markedly decreased the expression of SAG, enhancing the susceptibility of heat shock-induced apoptosis. Taken together, these results indicate that SAG may play an important role in regulating the apoptosis induced by heat shock presumably through maintaining the cellular redox status.

Protein N-acylation: H2O2-mediated covalent modification of protein by lipid peroxidation-derived saturated aldehydes

Various lines of evidence indicate that the oxidative modification of protein and the subsequent accumulation of the degenerated proteins have been found in cells and tissues during aging, oxidative stress, and in a variety of pathological states. The critical agents that give rise to this protein degeneration may be represented by aldehydes. Although the covalent modification of proteins by aldehydes alone has been well-studied, the effect of reactive oxygen species, such as H2O2, upon aldehyde modification of the protein has received little attention. We have now established a unique protein modification in which H2O2 and, to a lesser extent, alkyl hydroperoxides mediate the binding of alkanals to the lysine residues of protein to generate structurally unusual N-acylation products. Upon the reaction of a lysine-containing peptide, N(alpha)-benzoylglycyl-lysine, with hexanal in the presence of H2O2, a product containing one molecule of hexanal per peptide was detected. On the basis of the chemical and spectroscopic evidence, the product was identified to be the acylation product, N(epsilon)-hexanoyllysine. H2O2 mediated the N-acylation of the lysine derivative by the saturated aldehydes of 1-6 carbons in length. The H2O2-mediated acylation of the protein was immunochemically confirmed by reaction of the proteins with hexanal in the presence of H2O2. Furthermore, the enhanced N-acylations (N-acetylation and N-hexanoylation) were also observed in the kidney of rats exposed to ferric nitrilotriacetate, a well-characterized inducer of oxidative stress. Mechanistic studies using a phosphonium lysine derivative suggest a Baeyer-Villiger-like reaction proceeding through peroxide addition to the aldehyde Schiff base. These data suggest that the hydroperoxides, including H2O2, might be involved not only in the oxidative modification of protein but also in the covalent binding of the saturated aldehydes to proteins under oxidative stress.

Skin DNA photodamage and its biological consequences

It is well established that ultraviolet (UV) radiation from sunlight damages skin cells' DNA. Wavelengths in the UVB range are absorbed by DNA and can induce mutagenic lesions such as pyrimidine dimers. On the other hand, genotoxic effects of solar UVA are mainly mediated by the activation of endogenous photosensitizers resulting in the generation of a local oxidative stress. Exogenous chemicals, such as drugs like psoralens or fluoroquinolones, sometimes amplify UV-induced harmful effects. DNA damage can lead to mutations and genetic instability. This is one of the reasons why sunlight overexposure increases the risk of skin cancer. But DNA photolesions can also be involved in other skin-specific responses to UV radiation: erythema, immunosuppression, and melanogenesis are examples reported in the literature. The aim of this short review is to summarize the general knowledge in the field of UV-induced DNA damage. Besides the biological consequences of DNA photolesions, this article also deals with technologies used for their detection and shows how helpful such approaches can be to assess photoprotection provided by sunscreens.

Increased levels of 8-hydroxydeoxyguanosine and its relationship with lipid peroxidation and antioxidant vitamins in lung cancer

BACKGROUND

Reactive oxygen species produced either endogenously or exogenously can attack lipids, proteins and DNA in human cells and cause potentially deleterious consequences. In recent years, their role in the pathogenesis of lung cancer and the preventive effect of antioxidants have been studied extensively. In this study, our aim was to investigate the levels of 8-hydroxy-2'-deoxyguanosine (8OHdG) and malondialdehyde as a marker for the effects of reactive oxygen species on DNA and lipids, the levels of antioxidant vitamins and the correlations between these oxidative stress markers and antioxidants in lung cancer.

METHODS

Serum malondialdehyde, beta-carotene, retinol, and vitamins C and E were measured by high-performance liquid chromatography methods in fasting blood samples and 8OHdG was measured by gas chromatography-mass spectrometry in 24-h urine samples of patients with lung cancer (n=39) and healthy controls (n=31).

RESULTS

The levels of 8OHdG and malondialdehyde were significantly higher (p<0.05 and p<0.005, respectively) and beta-carotene, retinol, and vitamins C and E (p<0.0001, p<0.0001, p<0.0001, and p<0.05, respectively) were significantly lower in patients than in controls. There was a significantly positive correlation between 8OHdG and malondialdehyde (r=0.463, p=0.01) and a negative correlation between the levels of 8OHdG and retinol (r=-0.419, p=0.021) in the patient group.

CONCLUSIONS

Our results demonstrate that the oxidant/antioxidant balance was spoiled in favor of lipid peroxidation and DNA damage in lung cancer patients. Significant increases in the levels of malondialdehyde and 8OHdG and decreases in the levels of antioxidants suggest the possible involvement of oxidative stress in lung cancer.

Epigallocatechin gallate, a constituent of green tea, regulates high glucose-induced apoptosis

A high concentration of glucose has been implicated as a causal factor in initiation and progression of diabetic complications, and there is evidence to suggest that hyperglycemia increases the production of free radicals and oxidative stress. Therefore, compounds that scavenge reactive oxygen species may confer regulatory effects on high glucose-induced apoptosis. Epigallocatechin gallate (EGCG), the major polyphenolic of green tea, is reported to have an antioxidant activity. We investigated the effect of EGCG on high glucose-induced apoptosis in U937 cells. Upon exposure to 35 mM glucose for 2 days, there was a distinct difference between untreated cells and cells pre-treated with 1 microM EGCG for 2 h in regard to cellular redox status and oxidative DNA damage to cells. EGCG pre-treated cells showed significant suppression of apoptotic features such as DNA fragmentation, damage to mitochondrial function, and modulation of apoptotic marker proteins upon exposure to high glucose. This study indicates that EGCG may play an important role in regulating the apoptosis induced by high glucose presumably through scavenging of reactive oxygen species.

Ursolic acid regulates high glucose-induced apoptosis

A high concentration of glucose has been implicated as a causal factor in initiation and progression of diabetic complications and there is evidence to suggest that hyperglycemia increases the production of free radicals and oxidative stress. Therefore, compounds that scavenge reactive oxygen species (ROS) may confer regulatory effects on high glucose-induced apoptosis. Ursolic acid (UA), a pentacyclic triterpene, is reported to have an antioxidant activity. We investigated the effect of UA on high glucose-induced apoptosis in U937 cells. Upon exposure to 35 mM glucose for two days, there was a distinct difference between untreated cells and cells pre-treated with 50 nM UA for 2 h in regard to cellular redox status and oxidative DNA damage to cells. UA pre-treated cells showed significant suppression of apoptotic features such as DNA fragmentation, damage to mitochondrial function and modulation of apoptotic marker proteins upon exposure to high glucose. This study indicates that UA may play an important role in regulating the apoptosis induced by high glucose presumably through scavenging of ROS.

Regulation of ionizing radiation-induced apoptosis by mitochondrial NADP+-dependent isocitrate dehydrogenase

Ionizing radiation induces the production of reactive oxygen species, which play an important causative role in apoptotic cell death. By supplying NADPH for antioxidant systems, we recently demonstrated that the control of mitochondrial redox balance and the cellular defense against oxidative damage are some of the primary functions of mitochondrial NADP(+)-dependent isocitrate dehydrogenase (IDPm). In this study, we demonstrate that modulation of IDPm activity in U937 cells regulates ionizing radiation-induced apoptosis. When we examined the regulatory role of IDPm against ionizing radiation-induced apoptosis in U937 cells transfected with the cDNA for mouse IDPm in sense and antisense orientations, a clear inverse relationship was observed between the amount of IDPm expressed in target cells and their susceptibility to apoptosis. Upon exposure to 2 gray gamma-irradiation, there was a distinct difference between the IDPm transfectant cells in regard to the morphological evidence of apoptosis, DNA fragmentation, cellular redox status, oxidative damage to cells, mitochondrial function, and the modulation of apoptotic marker proteins. In addition, transfection of HeLa cells with an IDPm small interfering RNA decreased the activity of IDPm, enhancing the susceptibility of radiation-induced apoptosis. Taken together, these results indicate that IDPm may play an important role in regulating the apoptosis induced by ionizing radiation, and the effect of IDPm small interfering RNA on HeLa cells offers the possibility of developing a modifier of radiation therapy.

Antioxidant enzyme inhibitors enhance peroxynitrite-induced cell death in U937 cells

Peroxynitrite, a potent physiological inorganic toxin, is known to play a critical role in cellular oxidative damage. The protective role of antioxidant enzymes against peroxynitrite-induced oxidative damage in U937 cells was investigated in control and cells pre-treated with diethyldithiocarbamic acid, aminotriazole, and oxlalomalate, specific inhibitors of superoxide dismutase, catalase, and NADP(+)-dependent isocitrate dehydrogenase, respectively. Upon exposure to 1 mM 3-morpholinosydnomine N-ethylcarbamide (SIN-1), a generator of peroxynitrite through the reaction between nitric oxide and superoxide anion, to U937 cells, the viability was lower and the protein oxidation, lipid peroxidation and oxidative DNA damage reflected by an increase in 8-hydroxy-2'-deoxyguanosine, were higher in the inhibitor-treated cells as compared to the control cells. We also observed the significant increase in the endogenous production of reactive oxygen species, as measured by the oxidation of 2'7'-dichlorodihydrofluorescin as well as the significant decrease in the intracellular GSH level in the inhibitor-treated U937 cells upon exposure to SIN-1. These results suggest that antioxidant enzymes play an important role in cellular defense against peroxynitrite-induced cell death.

Protective effect of curcumin on γ-radiation induced DNA damage and lipid peroxidation in cultured human lymphocytes

The present work is aimed at evaluating the radioprotective effect of curcumin, a naturally occurring phenolic compound on gamma-radiation induced toxicity. The cellular changes were estimated by using lipid peroxidative indices like thiobarbituric acid reactive substances (TBARS), the antioxidants superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and reduced glutathione (GSH). The DNA damage was analysed by using cytokinesis blocked micronucleus assay and dicentric aberration (DC). The gamma-radiation at different doses (1, 2 and 4Gy) were found to significantly increase micronuclei (MN), DC frequencies and TBARS level whereas the levels of GSH and antioxidant enzymes were significantly decreased. The maximum damage to lymphocytes was observed at 4Gy irradiation. Curcumin pretreatment (1, 5 and 10microg/ml) significantly decreased the frequency of MN and DC. The levels of TBARS decreased and activities of SOD, CAT and GPx significantly increased along with GSH levels. At 1Gy irradiation all the concentrations of curcumin (1, 5 and 10microg/ml) significantly protected the lymphocytes from radiation damage. At 2Gy irradiation, 5 and 10microg/ml of curcumin showed significant radioprotection. Since the highest damage was observed at 4Gy irradiation both 1 and 5microg/ml of curcumin pretreatment were not sufficient to protect the lymphocytes from radiation damage but 10microg/ml of curcumin significantly protected the cultured lymphocytes from radiation damage. Thus, pretreatment with curcumin gives protection to lymphocytes against gamma-radiation induced cellular damage.

Dietary supplementation with 11trans- and 12trans-18:1 and oxidative stress in humans

BACKGROUND

High consumption of trans fat has been associated with high oxidative stress in humans, which could increase the risk of the development or acceleration of several diseases, such as atherosclerosis, cancer, and type 2 diabetes.

OBJECTIVE

Several urinary and blood biomarkers of oxidative stress [8-iso-prostaglandin-F(2alpha) (PGF(2alpha)), 15-keto-dihydro-PGF(2alpha), and 7,8-dihydro-8-oxo-2'-deoxy-guanosine in urine and alpha-,beta-,gamma-,delta-tocopherol, and retinol in plasma] were monitored to evaluate the oxidative stress induced by dietary supplementation of 11trans- and 12trans-18:1 isomers in humans during a 6-wk intervention.

DESIGN

After a 14-d adaptation period free of trans fatty acid supplementation (baseline), the test group (n = 12) received 3.0 g 11trans-18:1/d and 3.0 g 12trans-18:1/d (Sigma 6.0 g/d), and the control group (n = 12) consumed a control oil free of trans fatty acids and conjugated linoleic acids for 6 wk.

RESULTS

The postintervention concentration of urinary 8-iso-PGF(2alpha) (free radical-induced lipid peroxidation) in the test group was significantly higher than baseline and significantly higher than that observed in the control group. The concentrations of 15-keto-dihydro-PGF(2alpha) (cyclooxygenase-mediated inflammatory response indicator) and 7,8-dihydro-8-oxo-2'-deoxy-guanosine (oxidative DNA damage) were not affected by the 11trans- and 12trans-18:1 supplementation.

CONCLUSIONS

Although an increase in urinary 8-iso-PGF(2alpha) was observed and the effects of prolonged high (ie, >5.0 g/d) consumption of trans fat could be relevant to the development of disease, the mean intakes of 11trans- and 12trans-18:1 in Europeans are estimated to be significantly below the amounts administered in this study (ie, 6.0 g/d); such low intakes could minimize the possible risk of detrimental effects on human health.

Glycation-induced inactivation of antioxidant enzymes and modulation of cellular redox status in lens cells

Oxidative mechanisms are thought to have a major role in cataract formation and diabetic complications. Antioxidant enzymes play an essential role in the antioxidant system of the cells that work to maintain low steady-state concentrations of the reactive oxygen species. When HLE-B3 cells, a human lens cell line were exposed to 50-100 mM glucose for 3 days, decrease of viability, inactivation of antioxidant enzymes, and modulation of cellular redox status were observed. Significant increase of cellular oxidative damage reflected by lipid peroxidation and DNA damage were also found. The glycation-mediated inactivation of antioxidant enzymes may result in the perturbation of cellular antioxidant defense mechanisms and subsequently lead to a pro-oxidant condition and may contribute to various pathologies associated with the long term complications of diabetes.

Antioxidant enzyme inhibitors enhance nitric oxide-induced cell death in U937 cells

Nitric oxide (NO), a radical species produced by many types of cells, is known to play a critical role in many regulatory processes, yet it may also participate in collateral reactions at higher concentrations, leading to cellular oxidative damage. The protective role of antioxidant enzymes against NO-induced oxidative damage in U937 cells was investigated in control and cells pre-treated with diethyldithiocarbamic acid, aminotriazole, and oxlalomalate, specific inhibitors of superoxide dismutase, catalase, and NADP(+)-dependent isocitrate dehydrogenase, respectively. Upon exposure to 1 mM S-nitroso-N-acetylpenicillamine (SNAP), the nitric oxide donor, to U937 cells, the viability was lower and the protein oxidation, lipid peroxidation and oxidative DNA damage reflected by an increase in 8-hydroxy-2'-deoxyguanosine, were higher in inhibitor-treated cells as compared to control cells. We also observed the significant increase in the endogenous production of reactive oxygen species, as measured by the oxidation of 2'7'-dichlorodihydrofluorescin as well as the significant decrease in the intracellular GSH level in inhibitor-treated U937 cells upon exposure to NO. Upon exposure to 0.2 mM SNAP, which induced apoptotic cell death, a clear inverse relationship was observed between the control and inhibitor-treated U937 cells in their susceptibility to apoptosis. These results suggest that antioxidant enzymes play an important role in cellular defense against NO-induced cell death including necrosis and apoptosis.

Genotoxicity and oxidative stress of the mutagenic compounds formed in fumes of heated soybean oil, sunflower oil and lard

This study was to investigate the genotoxicity and cytotoxicity of the oil fumes formed from heating three common commercial cooking oils (soybean oil, sunflower oil, and lard) on human lung carcinoma pulmonary type II-like epithelium cell (A-549 cell). The major alkenal mutagenic compounds (trans-trans-2,4-decadienal, t-t-2,4-DDE; trans-trans-2,4-nonadienal, t-t-2,4-NDE; trans-2-decenal, t-2-DCA and trans-2-undecenal, t-2-UDA) contained in three oil fumes and their effects on the induction of reactive oxygen species (ROS) were also studied. It was found that the most potent mutagenic compound (t-t-2,4-DDE) of oil fumes was 66.4, 35.9 and 40.3 microg/g in soybean oil, sunflower oil and lard, respectively. The results indicated that the methanolic extracts of oil fumes could apparently lead to cytotoxicity and oxidative DNA damage. Glutathione (GSH) contents and the activities of antioxidant enzymes such as GSH reductase, and GSH S-transferase were adversely reduced by the methanolic extracts of oil fumes. When human A-549 cells were exposed to the methanolic extracts of oil fumes for 30 min, there was an increase in the formation of intracellular ROS, which was determined by dichlorofluorescein assay. Moreover, the methanolic extracts of oil fumes caused significant (p<0.05) oxidative damage through the 8-hydroxy-2'-deoxyguanosine formation in A-549 cells at the concentrations from 50 to 200 microg/ml. These results demonstrated that the DNA damage in A-549 cells, induced by cooking oil fumes, was related to the ROS formation. It is inferred that women exposed to emitted fumes from cooking oil were at higher risk of contracting lung cancer.