Rapid and reliable quantification of urinary malondialdehyde by HILIC-MS/MS: A derivatization-free breakthrough approach.

BACKGROUND: The development of fast analytical methods is crucial for the research, discovery, and confirmation of crucial biomarkers. Furthermore, the implementation of fast analytical strategies contributes to efficient and time-effective procedures. In this sense, analysis of malondialdehyde (MDA) has become an important tool for understanding the role of oxidative stress in various diseases and for evaluating the efficacy of therapeutic interventions. RESULTS: A rapid and robust liquid chromatography tandem mass spectrometry method (HPLC-MS/MS) has been developed to determine endogenous amounts of malondialdehyde (MDA) in human urine without any associated derivatization reaction. MDA was separated in 4 min through a Urea-HILIC column and was analyzed using a triple quadrupole mass spectrometer in negative electrospray ionization mode. With a 50-fold dilution as the only sample pretreatment after alkaline hydrolysis, no matrix effect was present, which allowed for a fast and simple quantification by means of an external standard calibration with a limit of detection of 0.20 ng mL-1. The whole methodology was validated by analyzing unspiked and spiked urine samples from ten healthy individuals and comparing with the results obtained by the standard addition method. MDA was detected in all cases, with natural concentrations varying from 0.11 ± 0.03 to 0.31 ± 0.03 mg g-1 creatinine. Accuracies were found to be satisfactory, ranging from 95 % to 101 %. The proposed method also exhibited good repeatability and reproducibility (RSD<15 %) for four quality control levels. SIGNIFICANCE: The main significance of this method is the avoidance of a derivatization reaction for the determination of urinary MDA, this constituting a step forward when compared with previous literature. This breakthrough not only streamlines time analysis to less than 5 min per sample but also results in a more robust procedure. Consequently, the method here developed could be applied to subsequent future research involving the determination of MDA as a lipid peroxidation biomarker, where simple, rapid, and reliable methods could represent a significant improvement.

Effect of antioxidant-rich kindergarten meals on oxidative stress biomarkers in healthy 5-6-year-old children: a randomized controlled trial.

As children spend up to 9 h a day in kindergarten, the main purpose of our study was to evaluate the effect of antioxidant-rich kindergarten meals on oxidative stress biomarkers (OSBs) in healthy children. In the randomized control trial with a follow-up, healthy 5-6-year-old children from six kindergartens were randomly divided into a prototype group (PG, n = 40) and a control group (CG, n = 17). PG followed a 2-week antioxidant-rich kindergarten meal plan (breakfast, lunch, and two snacks), and CG followed their standard kindergarten meal plans. Outside the kindergartens, participants ate as usual. We used a consecutive 7-day dietary record inside and outside the kindergarten and the national dietary assessment tool OPEN to assess the total dietary antioxidant capacity (dTAC) of the consumed foods. Malondialdehyde (MDA), 8-hydroxy-2-deoxyguanosine (8-OHdG), and four F2-isoprostane were measured in fasting urine on days 1 and 15. We also measured total antioxidant power (PAT) and hydroperoxides (d-ROMs) in fasting serum on day 15 and obtained the value of the oxidative stress index (OSI). We used a Welch two-sample t-test and multiple regression analysis to compare the prototype and control groups and a nonparametric Wilcoxon signed rank exact test to compare pre- and post-intervention results in urine. Antioxidant-rich kindergarten meals contributed to a significantly (p < 0.05) higher intake of dTAC in PG participants compared to standard meals in CG participants (8.6 vs. 2.8 mmol/day). We detected a negative correlation between dTAC intake and d-ROMs and between dTAC intake and OSI (r = - 0.29, p = 0.043 and r = - 0.31, p = 0.032, respectively). A significant decrease in urinary 8-iso-15-prostaglandin-F-2 alpha was detected in PG participants between days 1 and 15; however, no other intra-individual significant differences in urinary OSBs were found.  Conclusion: Antioxidant-rich food in kindergarten is warranted due to its potential health-protective effect. Additionally, we present original data on the average levels of urinary and serum OSBs in healthy 5-6-year-old children.  Trial registration: The study was registered at ClinicalTrials.gov, on February 5, 2020 ( https://clinicaltrials.gov/ct2/show/NCT04252105 ). What is Known: • Kindergartens are recognized as promising environments for public health measures. • A diet rich in antioxidants can reduce OSBs and, consequently, the risk of developing NCDs. What is New: • Antioxidant-rich kindergarten diet can ensure a protective intake of dTAC in children. • Original data on serum oxidative stress biomarkers (d-ROMs, PAT, and OSI) and urinary oxidative stress biomarkers (MDA, 8-OHdG, and F2 isoprostanes) in healthy 5-6-year-old children.

Phthalate Exposure and Coronary Heart Disease: Possible Implications of Oxidative Stress and Altered miRNA Expression.

The relationship between phthalate exposure and coronary heart disease (CHD) is still unclear. This study aimed to investigate the association between phthalate exposure and CHD and determine the possible atherogenic mechanisms of phthalates by assessing oxidative stress and altering miRNA expression. This case-control study included 110 participants (55 CHD patients and 55 healthy controls). The levels of oxidative stress markers, malondialdehyde (MDA), and superoxide dismutase (SOD), and the expression of miRNA-155 (miR-155) and miRNA-208a (miR-208a), were measured and correlated with the urinary mono-2-ethylhexyl phthalate (MEHP). Highly significant differences were detected between the CHD cases and the control group regarding MEHP, MDA, SOD, miR-155, and miR-208a (p-value < 0.001). Spearman correlations revealed a significant positive correlation between MDA and MEHP in urine (P = 0.001 and rs = 0.316) and a significant negative correlation between SOD and MEHP in urine (P < 0.001 and rs = -0.345). Furthermore, significant positive correlations were observed between miR-155 and urinary MEHP (P = 0.001 and rs = 0.318) and miR-208a and urinary MEHP (P < 0.001 and rs = -0.352). This study revealed an association between phthalate exposure, as indicated by urinary MEHP and CHD; altered expression of miR-155 and miR-208a and oxidative stress could be the fundamental mechanisms.

8-Hydroxy-2'-deoxyguanosine and malondialdehyde in plasma and their association with disease severity in 20 cats with chronic kidney disease.

OBJECTIVES: Oxidative stress is associated with the development and progression of chronic kidney disease (CKD) in humans. The aim of this study was to evaluate the concentrations of oxidative stress markers, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA), in the plasma and urine of cats with different stages of CKD. METHODS: Plasma and urine samples were collected from cats with CKD that were referred to the Veterinary Medical Center of the University of Tokyo between April 2019 and October 2022. Plasma and urine samples were collected from healthy cats (n = 6 at most), cats with stage 2 CKD (n = 8) and stage 3-4 CKD (n = 12), and cats with idiopathic cystitis (disease control, n = 5). Plasma and urine concentrations of 8-OHdG and MDA were measured using ELISA and thiobarbituric acid reactive substances assay kits, respectively. RESULTS: The median plasma 8-OHdG concentrations were 0.156 ng/ml (<0.125-0.210 ng/ml) in the healthy group, <0.125 ng/ml (range <0.125 ng/ml) in the idiopathic cystitis group, 0.246 ng/ml (range 0.170-0.403 ng/ml) in cats with stage 2 CKD and 0.433 ng/ml (range 0.209-1.052 ng/ml) in cats with stage 3-4 CKD. Concentrations in stage 3-4 CKD were significantly higher than those in the healthy and disease control groups. Plasma MDA concentrations were low in the healthy and disease control groups and significantly higher in cats with stage 3-4 CKD. In every cat with CKD, plasma 8-OHdG and MDA concentrations were positively correlated with plasma creatinine concentrations (8-OHdG, rs = 0.68; MDA, rs = 0.67). Urinary 8-OHdG/urinary creatinine (u-CRE) and urinary MDA/u-CRE levels did not differ significantly between the groups; however, it was difficult to evaluate them because of the small sample size. CONCLUSIONS AND RELEVANCE: This report shows that plasma 8-OHdG and MDA concentrations increase with the severity of feline CKD. These markers may be useful for assessing oxidative stress in cats with CKD.

Passive smoking and urinary oxidative biomarkers: A pilot study of healthy travelers from Los Angeles to Beijing.

There is a great heterogeneity in smoking prevalence and tobacco control policy across different countries. However, it is unknown whether this heterogeneity could cause increased passive smoking and adverse health effects among international travelers. In this pilot study, we collected 190 urine samples from 26 Los Angeles residents before (LA-before), during (Beijing), and after (LA-after) a 10-week visit to Beijing to measure biomarkers of passive smoking (cotinine), exposure to polycyclic aromatic hydrocarbons (OH-PAHs), and oxidative stress (malondialdehyde, 8-isoprostane, and uric acid). The geometric mean concentrations of urinary cotinine were 0.14, 1.52, and 0.22 µg/g creatinine in LA-before, Beijing, and LA-after, respectively. Likewise, OH-PAH levels were significantly higher in Beijing as compared to LA-before or LA-after, in association with the urinary cotinine levels. One-fold increase in urinary cotinine levels was associated with 10.1% (95% CI: 5.53-14.8%), 8.75% (95% CI: 2.33-15.6%), and 25.4% (95%CI: 13.1-39.1%) increases in urinary levels of malondialdehyde, 8-isoprotane, and uric acid, respectively. OH-PAHs mediated 9.1-23.3% of the pro-oxidative effects associated with passive smoking. Taken together, our findings indicate that traveling to a city with higher smoking prevalence may increase passive smoking exposure, in association with pro-oxidative effects partially mediated by PAHs.

Association of maternal dietary patterns during pregnancy with small-for-gestational-age infants: Korean Mothers and Children's Environmental Health (MOCEH) study.

BACKGROUND: Nutrients that support the desired growth and development of the fetus (i.e., micronutrients like folate, iron, and zinc) have been associated with birth outcomes, such as gestational age at delivery and birth weight. OBJECTIVES: We characterized the maternal dietary patterns that explain the maximum variation in folate, iron, and zinc intakes in pregnant Korean women using reduced-rank regression (RRR) and investigated the association of these patterns with small-for-gestational-age (SGA) risk. METHODS: A total of 1158 pregnant Korean women at 12-28 weeks of gestation and their newborns were recruited for the Mothers and Children's Environmental Health (MOCEH) study between 2006 and 2010. A semiquantitative FFQ was collected from the women, and RRR was used to derive their dietary patterns. Log-transformed maternal intakes of folate, iron, and zinc were selected as the intermediate response variables to extract dietary patterns. Infant birth outcome measurements were obtained from hospital records. Associations were assessed by logistic regression with adjustment for confounding factors. RESULTS: Three dietary patterns were identified. Pattern 1, characterized by high intakes of grains, green/yellow and light-colored vegetables, kimchi, legumes, fruits, meat, eggs, fish, seaweeds, tofu/soymilk, yogurt, and nuts, was associated with a lower risk of SGA in the highest quartile than in the lowest quartile (OR: 0.36; 95% CI: 0.14, 0.94). Especially, maternal dietary pattern 1 was negatively related to high-sensitivity C-reactive protein in the blood and malondialdehyde concentrations in the urine. No association was observed between other dietary patterns and SGA. CONCLUSION: Among pregnant Korean women, adherence to a dietary pattern characterized by high intakes of grains, green/yellow and light-colored vegetables, kimchi, legumes, fruits, meat, eggs, fish, seaweeds, tofu/soymilk, yogurt, and nuts is associated with a lower risk of delivering SGA infants.

In Vivo Evaluation of Dendropanax morbifera Leaf Extract for Anti-Obesity and Cholesterol-Lowering Activity in Mice.

Metabolic syndrome is a worldwide health problem, and obesity is closely related to type 2 diabetes, cardiovascular disease, hypertension, and cancer. According to WHO in 2018, the prevalence of obesity in 2016 tripled compared to 1975. D. morbifera reduces bad cholesterol and triglycerides levels in the blood and provides various antioxidant nutrients and germicidal sub-stances, as well as selenium, which helps to remove active oxygen. Moreover, D. morbifera is useful for treating cardiovascular diseases, hypertension, hyperlipidemia, and diabetes. Therefore, we study in vivo efficacy of D. morbifera to investigate the prevention effect of obesity and cholesterol. The weight and body fat were effectively reduced by D. morbifera water (DLW) extract administration to high-fat diet-fed C57BL/6 mice compared to those of control mice. The group treated with DLW 500 mg∙kg-1∙d-1 had significantly lower body weights compared to the control group. In addition, High-density lipoprotein (HDL) cholesterol increased in the group treated with DLW 500 mg∙kg-1∙d-1. The effect of DLW on the serum lipid profile could be helpful to prevent obesity. DLW suppresses lipid formation in adipocytes and decreases body fat. In conclusion, DLW can be applied to develop anti-obesity functional foods and other products to reduce body fat.

Associations between air pollution and cardio-respiratory physiological measures in older adults exercising outdoors.

We examined whether exercising indoors vs. outdoors reduced the cardio-respiratory effects of outdoor air pollution. Adults ≥55 were randomly assigned to exercise indoors when the Air Quality Health Index was ≥5 and outdoors on other days (intervention group, n = 37), or outdoors everyday (control group, n = 35). Both groups completed cardio-respiratory measurements before and after exercise for up to 10 weeks. Data were analyzed using linear mixed effect regression models. In the control group, an interquartile range increase in fine particulate matter (PM2.5) was associated with increases of 1.4% in heart rate (standard error (SE) = 0.7%) and 5.6% (SE = 2.6%) in malondialdehyde, and decreases of 5.6% (SE = 2.5%) to 16.5% (SE = 7.5%) in heart rate variability measures. While the hypothesized benefit of indoor vs. outdoor exercise could not be demonstrated due to an insufficient number of intervention days (n = 2), the study provides evidence of short-term effects of air pollution in older adults. ISRCTN #26552763.

The profile of urinary biomarkers in overactive bladder.

AIMS: In overactive bladder (OAB) research, different biomarkers have been proposed as diagnostic tools and may be used to create individual patient profiles. Assessing the diagnostic performance of biomarkers would better outline their utility. Therefore, our aim was to investigate the diagnostic value of four urinary biomarkers: human brain derived neurotrophic factor (hBDNF), malondialdehyde (MDA), h nerve growth factor (hNGF) and h 8-hydroxydeoxyguanosine in women with OAB. These are neurotrophins/oxidative stress markers that have been linked to lower urinary tract symptoms. METHODS: A total of 105 women were included in the study and distributed in two groups: a group with OAB (n = 53) and a control group (n = 50). The levels of the biomarkers were determined using enzyme-linked immunosorbent assay technique and they were compared between the groups. If the Mann-Whitney test demonstrated a statistically significant difference, receiver operating curves (ROC) analysis was undertaken. RESULTS: When normalized to urinary creatinine, hBDNF, MDA, and hNGF showed significantly increased values in women with OAB as compared to controls, whereas 8-OHdG showed no significant difference. The diagnostic performance of these biomarkers was analyzed based on the area under the ROC curve (AUC). MDA had the highest AUC (0.75), followed by hNGF (0.69) and hBDNF (0.67). CONCLUSIONS: Our findings suggest that MDA, a relatively novel biomarker in OAB research, has a fair performance as a diagnostic tool for OAB. Moreover, urinary neurotrophins (NGF and BDNF) as biomarkers may have a role in the diagnostic pathways of women with OAB symptoms.

Effect of particulate matter 2.5 exposure to urinary malondialdehyde levels of public transport drivers in Jakarta.

Background People who work long hours on the road are intensively exposed to high levels of fine particulate matters (PM2.5) which may lead to oxidative stress mechanisms in the human body that cause deleterious health problems. Malondialdehyde (MDA) is the major metabolite produced during lipid peroxidation metabolism that serves as a reliable biomarker for oxidative stress in cells. Objectives To identify the association between PM2.5 exposure and other characteristics with urinary MDA levels among public transport drivers in Jakarta. Methods A cross-sectional design was implemented by involving 130 public transport drivers of nine trajectories from Kampung Melayu Terminal, Jakarta. The continuous PM2.5 data were collected in personal measurement during one round trip of driving. Weight and height measurements were obtained to calculate body mass index (BMI) and structured questionnaires were completed to identify other characteristics. MDA levels were examined from the driver's urine right after driving and evaluated using TBARS analysis. Results The average of PM2.5 exposure was 91.56 ± 20.05 µg/m3 and MDA levels were 2.23 ± 1.57 nmoL/mL. Drivers with overweight and obese BMI had significantly higher MDA levels (2.66 ± 1.65 nmoL/mL) compared to those with normal and underweight BMI status (1.97 ± 1.47 nmoL/mL). Multiple linear regression analysis demonstrated low PM2.5 exposure, normal and underweight BMI status, and a long period of working as drivers were associated with MDA levels (p<0.05). Contrary to the prior study, PM2.5 exposure was negatively associated with MDA levels due to most drivers' BMI status being normal and underweight. Conclusion Our study suggests that the drivers who were obese and overweight should lose weight to lower the risk of increased MDA levels. We also suggest the drivers to consider maintaining their vehicle's ventilation system or using personal protection equipment (PPE) to avoid high PM2.5 exposure while driving.

LC-MS Quantification of Malondialdehyde-Dansylhydrazine Derivatives in Urine and Serum Samples.

We developed a robust analytical method for quantification of malondialdehyde (MDA) in urine and serum samples using dansylhydrazine (DH) as a derivatizing reagent. The derivatization procedure was partially carried out using an autosampler injection program to minimize errors associated with the low-volume addition of reagents and was optimized to yield a stable hydrazone derivative of MDA and its labeled d2-MDA analogue. The target MDA-DH derivatives were separated on an Agilent Zorbax Eclipse Plus Phenyl-Hexyl (3.0 × 100 mm, 3.5 µm) column. The mass-to-charge ratios of the target derivatives [(M+H)+ of 302 and 304 for MDA-DH and d2-MDA-DH, respectively] were analyzed in single ion monitoring mode using a single quadrupole mass spectrometer operated under positive electrospray ionization. The method limits of quantification were 5.63 nM (or 0.405 ng/mL) for urine analysis and 5.68 nM (or 0.409 ng/mL) for serum analysis. The quantification range for urine analysis was 5.63-500 nM (0.405-36.0 ng/mL) while the quantification range for serum analysis was 5.68-341 nM (0.409-24.6 ng/mL). The method showed good relative recoveries (98-103%), good accuracies (92-98%), and acceptable precisions (relative standard deviations 1.8-7.3% for inter-day precision; 1.8-6.1% for intra-day precision) as observed from the repeat analysis of quality control samples prepared at different concentrations. The method was used to measure MDA in individual urine samples (n = 287) and de-identified archived serum samples (n = 22) to assess the overall performance of the method. The results demonstrated that our method is capable of measuring urinary and serum levels of MDA, allowing its future application in epidemiologic investigations.

A Cross Sectional Study Evaluating Psychosocial Job Stress and Health Risk in Emergency Department Nurses.

Nurses experience psychosocial work stress that may negatively affect physical and mental health over time. In this cross-sectional study we investigated prevalence of job stress and oxidative stress in nurses, and determined if significant relationships exist between higher job stress scores and demographic factors and working conditions. Emergency department nurses (n = 42) were recruited from a University Hospital following Institutional Review Board approval. Job stress indicators, effort-reward ratio and overcommitment were evaluated from survey questionnaires using the effort-reward imbalance model, and associations with age, sex, body mass index, and working conditions were measured by logistic regression analysis. Oxidative stress biomarkers, 8-isoprostane, malondialdehyde, and antioxidant levels were measured from urine specimens. Job stress was prevalent with effort-reward ratio > 1 in 93% and overcommitment > 50 in 83% of the study participants. Age, body mass index, years of experience, weekend work, work hours per week, and shift work showed strong associations with effort-reward ratio and overcommitment scores. Malondialdehyde was higher in participants with high overcommitment. We report that psychosocial job stress is prevalent among nurses, as revealed by the high effort-reward and overcommitment scores. Job stress may be reduced through implementation of appropriate stress reduction interventions.

Health effect research on Hebei Spirit Oil Spill (HEROS) in Korea: a cohort profile.

PURPOSE: The Hebei Spirit Oil Spill occurred on 7 December 2007 and resulted in the spillage of 12 547 kl of crude oil on the coastline near Taean. Historically, this was the largest oil spill in Korean water. The health effect research on Hebei Spirit Oil Spill (HEROS) is a prospective cohort study that aimed to evaluate the long-term health effects of oil spill exposure on residents in the affected community. PARTICIPANTS: The Taean Environmental Health Center initially enrolled adults, adolescents and children living in Taean in 2009 and 2010. Follow-up surveys of participating adults and children were conducted every other year. By 2017, a total of 9585 adults and 2216 children and adolescents were enrolled. Of these, 294 adults and 102 children and adolescents were included in all subsequent surveys. FINDINGS TO DATE: Children who lived closer to the oil spill site exhibited a lower level of pulmonary function and higher prevalence of allergic rhinitis, than those who lived further away from the oil spill site. Adults who lived in a highly exposed area or participated in clean-up work had higher urine levels of the oxidative stress biomarkers malondialdehyde and 8-hydroxydeoxyguanosine. Changes in haematological parameters during a 3-year period were observed in residents of both sexes in highly exposed areas, in addition to increases in respiratory diseases and mental health problems in female and male participants, respectively. FUTURE PLANS: The findings of this study will better enable policy makers to develop environmental health policies intended to prevent adverse health effects in residents of communities affected by oil spills, as well as policies regarding the management of future oil accidents. The HEROS study will continue to follow participants in future and will be updated to enable an investigation of long-term health effects.

Effects of reduced exposure to cigarette smoking on changes in biomarkers of potential harm in adult smokers: results of combined analysis of two clinical studies.

Purpose: Nonconventional vapor products (NVP), designed to reduce exposure to cigarette smoke toxicants (CSTs), could cause changes in biomarkers of potential harm (BoPH). Although, NVPs reduced CSTs exposure compared to conventional cigarettes (CC), the changes in the BoPH values varied among the studies. Hence, further information on BoPH using NVPs is needed. Material and methods: The data of two similarly designed studies using a kind of NVP, a noncombustion and nonheating inhaler type of smokeless tobacco product (NCIT) used under 31-day confinement, were pooled, and the differences in 15 BoPH between smokers and nonsmokers at baseline and between the 1 mg tar CC (CC1) group and NCIT group at Day 28/29 were analyzed. Results: At baseline, the levels of eight BoPH (red blood cells, white blood cells, 8-epi-prostaglandin F2α, 8-hydroxy-2'-deoxyguanosine, malondialdehyde, 11-dehydrothromboxane B2, total cholesterol and glucose) were significantly different between smokers and nonsmokers. At Day 28/29, the levels of six BoPH were significantly different between NCIT and CC1 (8-epi-prostaglandin F2α, malondialdehyde, 11-dehydrothromboxane B2: CC1 > NCIT, total bilirubin, low-density lipoprotein cholesterol and total cholesterol: CC1 < NCIT). Conclusions: Reduced exposure to CSTs has favorable effects on BoPH associated with oxidative stress, antioxidant capacity and platelet activation/coagulation but not in lipid metabolism.

Urinary mutagenicity and other biomarkers of occupational smoke exposure of wildland firefighters and oxidative stress.

Background: Wildland firefighters conducting prescribed burns are exposed to a complex mixture of pollutants, requiring an integrated measure of exposure. Objective: We used urinary mutagenicity to assess if systemic exposure to mutagens is higher in firefighters after working at prescribed burns versus after non-burn work days. Other biomarkers of exposure and oxidative stress markers were also measured. Methods: Using a repeated measures study design, we collected urine before, immediately after, and the morning after a work shift on prescribed burn and non-burn work days from 12 healthy subjects, and analyzed for malondialdehyde (MDA), 8-isoprostane, 1-hydroxypyrene (OH-pyrene), and mutagenicity in Salmonella YG1041 +S9. Particulate matter (PM2.5) and carbon monoxide (CO) were measured by personal monitoring. Light-absorbing carbon (LAC) of PM2.5 was measured as a surrogate for black carbon exposure. Linear mixed-effect models were used to assess cross-work shift changes in urinary biomarkers. Results: No significant differences occurred in creatinine-adjusted urinary mutagenicity across the work shift between burn days and non-burn days. Firefighters lighting fires had a non-significant, 1.6-fold increase in urinary mutagenicity for burn versus non-burn day exposures. Positive associations were found between cross-work shift changes in creatinine-adjusted urinary mutagenicity and MDA (p = 0.0010), OH-pyrene (p = 0.0001), and mass absorption efficiency which is the LAC/PM2.5 ratio (p = 0.2245), respectively. No significant effect of day type or work task on cross-work shift changes in MDA or 8-isoprostane was observed. Conclusion: Urinary mutagenicity may serve as a suitable measure of occupational smoke exposures among wildland firefighters, especially among those lighting fires for prescribed burns.

Induction of two independent immunological cell death signaling following hemoglobinuria -induced acute kidney injury: In vivo study.

The main important clinical signs in acute kidney injury (AKI) after sever Hemiscorpius lepturus envenomation in patients is associated with proteinuria, hemolysis and hemoglobinuria. Unfortunately, our limited knowledge of molecular cell death mechanism in H. lepturus induced AKI restricts the development of desirable therapeutics. So, in the present study, the potential role of necroptosis and ferroptosis in H. lepturus induced AKI were investigated in male albino mice. The animals were administrated by SC injection of venom (1, 2.5, 5 and 10 mg/kg) based on LD50 determination. After 1 and 7 days, urinalysis, stereological assessments and gene expression of Ngal, Tnf-α, Tlr-4, Ripk3, Mlkl and Acsl4 were evaluated by real time PCR. Our data revealed that upregulation of renal Ngal expression is associated with the gene over expression of Tnf-α, Tlr-4, Ripk3 and Mlkl in venom treated kidneys. We observed that the Malondialdehyde (MDA) level was increased in dose-dependent manner similar to Acsl4 gene over expression suggesting a main role of ferroptosis in hemoglobinuria mediated AKI following envenomation. Moreover, transcriptional enhancement of Tlr-4and Tnf-α receptor can cause phosphorylation of Ripk3-Mlkl complex, collapse of membrane potential and DAMPs release which intensified the inflammation cytokines in kidney. Taken together, it supposes co-existence of two separate pathways of regulated necrosis and inflammatory environment provides a promising outlook in prevention and management of hemoglobinuria induced AKI following envenomation in clinical practice.

How stable is oxidative stress level? An observational study of intra- and inter-individual variability in urinary oxidative stress biomarkers of DNA, proteins, and lipids in healthy individuals.

Oxidative stress in humans is affected by the health and nutritional status as well as exposure to external environmental factors. To evaluate the effects of external factors, an assessment of baseline levels as well as diurnal variations in oxidative stress status of healthy individuals is needed. In this study, we examined intra- and inter-individual variability of oxidative stress biomarkers (OSBs) of lipids (malondialdehyde [MDA] and four F2-isoprostane isomers, namely, 8-isoprostaglandinF2α [8-PGF2α], 11ß-prostaglandinF2α [11-PGF2α], 15(R)-prostaglandinF2α [15-PGF2α], and 8-iso,15(R)-prostaglandinF2α [8,15-PGF2α]); proteins (o,o'-dityrosine [diY]); and DNA (8-hydroxy-2'-deoxyguanosine [8-OHdG]) in urine from healthy individuals. The significance of creatinine correction, which is typically used to account for urinary dilution, on OSB concentrations was evaluated. Analysis of 515 urine samples, collected longitudinally from 19 healthy individuals daily for over a month, showed inter-individual coefficient of variation (CV) in concentrations from 112% for MDA to 272% for 15-PGF2α. Intra-individual CV in concentrations ranged from 29% for 8-OHdG to 149% for 15-PGF2α. MDA was the most abundant OSB found in urine. The intra- and inter-individual variability in F2-isoprostane concentrations were higher than the values calculated for diY, 8-OHdG, and MDA. All seven OSB concentrations were significantly correlated with each other and with creatinine. Creatinine normalization of OSB concentrations improved predictability in OSB concentrations over time. Our results suggest that 8-OHdG, showing the highest ICC (0.96), yielded more reproducible measurements with a low CV, and is the most suitable biomarker of OSB in spot urine samples. The measured concentrations and diurnal variability in urinary OSB levels in healthy individuals reported in this study are useful as a benchmark for future toxicological and epidemiological studies.

Urinary metals and metal mixtures and oxidative stress biomarkers in an adult population from Spain: The Hortega Study.

INTRODUCTION: Few studies have investigated the role of exposure to metals and metal mixtures on oxidative stress in the general population. OBJECTIVES: We evaluated the cross-sectional association of urinary metal and metal mixtures with urinary oxidative stress biomarkers, including oxidized to reduced glutathione ratio (GSSG/GSH), malondialdehyde (MDA), and 8­oxo­7,8­dihydroguanine (8-oxo-dG), in a representative sample of a general population from Spain (Hortega Study). METHODS: Urine antimony (Sb), barium (Ba), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), molybdenum (Mo), vanadium (V) and zinc (Zn) were measured by ICPMS in 1440 Hortega Study participants. RESULTS: The geometric mean ratios (GMRs) of GSSG/GSH comparing the 80th to the 20th percentiles of metal distributions were 1.15 (95% confidence intervals [95% CI]: 1.03-1.27) for Mo, 1.17 (1.05-1.31) for Ba, 1.23 (1.04-1.46) for Cr and 1.18 (1.00-1.40) for V. For MDA, the corresponding GMRs (95% CI) were 1.13 (1.03-1.24) for Zn and 1.12 (1.02-1.23) for Cd. In 8-oxo-dG models, the corresponding GMR (95% CI) were 1.12 (1.01-1.23) for Zn and 1.09 (0.99-1.20) for Cd. Cr for GSSG/GSH and Zn for MDA and 8-oxo-dG drove most of the observed associations. Principal component (PC) 1 (largely reflecting non-essential metals) was positively associated with GSSG/GSH. The association of PC2 (largely reflecting essential metals) was positive for GSSG/GSH but inverse for MDA. CONCLUSIONS: Urine Ba, Cd, Cr, Mo, V and Zn were positively associated with oxidative stress measures at metal exposure levels relevant for the general population. The potential health consequences of environmental, including nutritional, exposure to these metals warrants further investigation.

The role of oxidative stress in cardiometabolic risk related to phthalate exposure in elderly diabetic patients from Shanghai.

The effect of human exposure to phthalates and consequent contribution to the development of cardiometabolic health problems is unknown. However, oxidative stress has been established as playing an important role in the pathogenesis of cardiometabolic outcomes. In this study, we aimed to explore whether exposure to phthalate metabolites could induce cardiometabolic risk by increasing oxidative stress in a diabetic population from Shanghai. We collected paired blood and urine samples from a total of 300 volunteers, and measured 10 phthalate metabolites in urine and biomarkers of oxidative stress from serum including glucose and lipid levels, and liver and kidney damage. The insulin resistance (IR) risk was assessed by the surrogate indices including homeostasis model assessment-insulin resistance (HOMA-IR) and triglyceride glucose (TyG). We used multivariable linear regression to assess the association between phthalates and these physiological parameters. Mediation and modification analyses were performed to identify the role that oxidative stress played in the underlying mechanisms. The results showed that most of the determined phthalate metabolites were positively associated with HOMA-IR, 8­hydroxy­2'­deoxyguanosine (8-OHDG), and malondialdehyde (MDA). In the mediation analysis, only γ­glutamiltransferase (GGT) was found to be a significant mediator of the association between phthalates and TyG. In the modification analysis, exposure to phthalates strengthened the association between oxidative stress (MDA and 8-OHDG) and HOMA-IR. Our findings demonstrate that exposure to phthalates might be positively associated with elevated IR and oxidative stress. The direct participation (mediation effect) of GGT might play an important mechanism in promoting IR.

Glycine mitigates renal oxidative stress by suppressing Nox4 expression in rats with streptozotocin-induced diabetes.

Glycine exerts renoprotective effects, but the mechanism remains unclear. Glycine is increasingly recognized as a factor that attenuates oxidative stress, a key mechanism underlying diabetic nephropathy. In this study, we investigated the effects of glycine on diabetic renal injury and oxidative stress by adding 1% glycine in the drinking water of rats with streptozotocin-induced diabetes for 20 weeks. Glycine levels decreased in the plasma and kidney homogenates of diabetic rats but were restored by oral glycine administration. In these diabetic rats, glycine attenuated renal damage, as evidenced by the decreased mesangial expansion, tubular interstitial fibrosis, and neutrophil gelatinase-associated lipocalin (NGAL) expression. Glycine also ameliorated the raise in urinary malondialdehyde (MDA) levels and partially restored renal glutathione levels in diabetic rats. Renal levels of the Nox4 mRNA and protein, a major source of renal oxidative stress, were suppressed by the treatment with glycine. Immunohistological analysis revealed that glycine had protective effects on the tubular area rather than the glomerular area. Our results strongly suggest that the protective effect of glycine on renal oxidative stress and structural damage may be linked to enhancement of GSH synthesis and suppression of renal Nox4 expression in diabetic rats.