Urinary Malondialdehyde Research Articles

Copper\u2013zinc imbalance induces kidney tubule damage and oxidative stress in a population exposed to chronic environmental cadmium

PurposeThis cross-sectional study aimed to assess the effect of environmental cadmium (Cd) exposure and essential metal imbalance on renal tubular damage and oxidative stress in 979 adults living in a Cd-polluted area near an abandoned copper (Cu) refinery.MethodsWe analyzed urinary Cd concentrations, renal tubular damage and oxidative stress markers, such as beta-2 microglobulin (β2-MG) and N-acetyl-β-d-glucosaminidase (NAG) activity and urine malondialdehyde (MDA) levels. The serum copper-to-zinc ratio (CZR) was used as an essential metal imbalance indicator. We divided the subjects into two Cd exposure groups based on the reference level of urinary Cd for renal dysfunction (2 μg/g creatinine).ResultsThe geometric mean concentration of urinary Cd in all subjects was 2.25 μg/g creatinine. In both low and high Cd exposure groups, urinary Cd levels were positively correlated with urinary NAG activity, but not with serum CZR. After multivariate adjustment, serum CZR was strongly associated with urinary β2-MG levels in the low Cd exposure group (β = 1.360, P = 0.019) and was significantly associated with urinary MDA levels, regardless of Cd exposure level. In addition, the risk of renal tubular damage was significantly associated with urinary Cd level, particularly in the lowest or highest CZR tertile groups.ConclusionsEssential metal imbalance may be a determinant of oxidative stress and renal tubular damage in a chronically Cd-exposed population, and proper zinc supplementation will be effective in preventing adverse health effects due to Cd exposure.

Effects of personal air pollutant exposure on oxidative stress: Potential confounding by natural variation in melatonin levels.

Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) are commonly used biomarkers of oxidative stress. However, their associations with air pollutant exposure have not been consistent across studies. We hypothesize that the inconsistency is partly due to confounding of circulating melatonin. We analyzed urinary 6-sulfatoxymelatonin (aMT6s), a surrogate of circulating melatonin, along with 8-OHdG and MDA, in 159 healthy adults who had not taken melatonin supplementation. Within the natural range of endogenously-generated aMT6s (0.3-93.5 ng/mg creatinine) measured in this study, increasing aMT6s levels were significantly associated with increasing concentrations of 8-OHdG and MDA. Measurements of PM2.5, ozone (O3), and nitrogen dioxide (NO2), coupled with time-activity data, were used to calculate time-averaged personal exposures 12 -hour (12h) and 24-hour (24h) prior to urine collection. Without controlling for aMT6s, the relationships between pollutant exposure and 8-OHdG or MDA were not clear. After controlling for aMT6s, an interquartile range (IQR) increase in 12h PM2.5 and 12h NO2 exposure was associated with 6.1% [95%CI: 1.6%-10.8%] and 8.6% [1.3%-16.5%] increase in MDA, respectively. An IQR increase in 12h O3 exposure was associated with a 5.7% [1.9%-9.7%] in 8-OHdG. The findings suggest the need for controlling for aMT6s as a confounder in using urinary 8-OHdG and MDA as biomarkers of oxidative stress related to short-term air pollution exposure.

Ameliorative effect of virgin olive oil against nephrotoxicity following sub-chronic administration of ethephon in male rats

BackgroundEthephon (EP) is the most famous plant growth regulator with different adverse effects on kidney function. Virgin Olive Oil (VOO) is considered as a natural source of antioxidant with beneficial effects. Thus, this study was conducted to investigate the effects of VOO on nephrotoxicity induced by EP in rats. Methods and materialsIn this study, 80 male rats (weighing 200–250 g) were divided into four groups including I: control group received normal saline as vehicle, II: received VOO, III: received EP (150 mg/kg/day) for 2 months, IV: received EP (150 mg/kg/day for 2 months, after 2-month pretreatment with VOO. VOO (2 mL/kg/day) and vehicle were administered by gastric gavage for 2 months. At the end, the animals were sacrificed, and their blood and kidneys were used for examinations. Isolated kidneys were used for histopathological and oxidative stress studies. ResultsSignificant increases were recorded in blood (neutrophils, monocytes) and urinary parameters as well as malondialdehyde (MDA) content in the group III compared to groups II and I (P˂0.05). Antioxidant enzymes significantly declined and histopathological alterations increased in the group III. In the group IV, significant decreases were recorded in blood and urinary parameters, MDA, and histopathological alterations and a significant increase were found in antioxidant enzymes compared to group III (P˂0.05). ConclusionsFindings of the present study demonstrated protective effects of VOO in prevention of kidneys against EP -induced toxicity in albino rats.

Edaravone-caffeine combination for the effective management of rotenone induced Parkinson’s disease in rats: An evidence based affirmative from a comparative analysis of behavior and biomarker expression

Restoration of cellular microenvironment is important in the treatment of neurodegenerative diseases for optimal functioning and survival of neurons. Oxidative stress has been proposed as one of the major pathogenic drivers in Parkinson’s disease. Parkinson’s model was developed by chronic administration of a pesticide rotenone that inhibits mitochondrial complex I resulting in generation of reactive oxygen species. In this study, our aim was to evaluate neuroprotective effect rendered by edaravone, a potent free radical scavenger in combination with caffeine, an effective inhibitor of adenosine A2A receptor as well as a proven antioxidant. Here we demonstrate that a three-week treatment with edaravone-caffeine combination was able to significantly diminish rotenone induced oxidative damage at the cellular level as well as muscle weakness and cognitive impairment generally associated with Parkinson’s disease. This effect is attributable to edaravone’s capability of scavenging the perxoynitrite free radical. Herein, we have assessed the levels of protein nitroxidation marker 3-nitrotyrosine in the striatum and lipid peroxidation marker malondialdehyde in striatum, cerebrospinal fluid, plasma and urine of rats. On the 21st day, statistical difference was observed in the striatal biomarker levels (p = 0.001) between the controls, treated and untreated groups. We discovered that when edaravone was co-administered with caffeine, the effect was more significant compared to the group solely treated with edaravone demonstrating a synergistic effect. Simultaneous therapeutic intervention with drug combination showed a pronounced decrease in oxidative damage markers as well as better muscle strength and cognition compared to the untreated groups.

Zataria multiflora and its main ingredient, carvacrol, affect on the renal function, histopathological, biochemical and antioxidant parameters in adriamycin-induced nephrotic rats

Oxidative stress has a major role in the nephrosis. In the present study, the effects of hydroalcoholic extract of Zataria multiflora (ZM) and carvacrol (CAR) were evaluated on the renal damage induced by adriamycin (ADR). The animals accidentally divided into four groups including: Control, ADR, ZM + ADR and CAR + ADR. The renal tissue, urine, and blood samples subjected to biochemical markers and histopathological evaluation. ADR significantly decreased glomerular filtration rate (GFR) while escalated urine protein excretion as well as protein clearance (p < .01 to p < .001). Also, ADR significantly reduced the antioxidants and boosted the malondialdehyde (MDA) compared to the control (p < .05 to p < .01). In groups treated by ZM and CAR, GFR, and antioxidants significantly increased, whereas urine protein excretion and MDA decreased (p < .05 to p < .001). ZM and CAR induced an improvement in ADR-induced renal damage by improving renal function as well as antioxidant activity.

A multibiomarker approach to evaluate the effect of polyaromatic hydrocarbon exposure on oxidative and genotoxic damage in tandoor workers.

We conducted a cohort study of tandoor workers to evaluate the relationship between the biomarkers of oxidative and genotoxic damage and exposure to polyaromatic hydrocarbons. A series of oxidative and genotoxic damage biomarkers, including urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), malondialdehyde (MDA) content, and tail moment (TM) by comet assay, was studied. A total of 76 tandoor workers and 79 demographically matched healthy individuals as controls were included. Our results showed that the tandoor workers had significantly higher urinary levels of 1-hydroxypyrene, urinary 8-OHdG, MDA content, and TM compared with the control population. The concentration of all these biomarkers increased with age in the control population as well as tandoor workers. In tandoor workers, significant variation in MDA, 8-oxodG (8-oxo-2'-deoxyguanosine) and TM concentration was detected between smokers (5.08 ± 1.72 nmol/mL, 16.01 ± 4.94 ng/mg creatinine, and 5.87 ± 0.98 µm, respectively) and nonsmokers (3.84 ± 0.98 nmol/mL, 13.74 ± 3.60 ng/mg creatinine, and 5.32 ± 0.69 µm, respectively). A similar pattern was obtained for the control population. We did not obtain significant variations for alcoholics and tobacco chewers. A significant increase in all these three biomarkers was observed with the increase in the period of work exposure in tandoor workers. Multivariate regression analysis also revealed that urinary 8-oxodG, MDA, and TM were statistically significantly related to age and period of work exposure. Overall, the present study showed that the exposure to wood smoke in tandoor workers under occupational conditions led to increased DNA damage because of oxidative stress and genotoxicity. These biomarkers, therefore, are good indices to assess oxidative DNA damage in these workers exposed to occupational genotoxicants. It is also necessary to make preventive changes in work conditions and lifestyle, which will help these occupational workers to lead a healthy life.

Factors Influencing the Level of Oxygen Free Radicals in Female Nursing Students

This study was conducted to investigate the levels of oxygen free radicals and related health factors in 201 female nursing students. The questionnaire was completed by the participants and their oxygen free radical levels were measured by urine test. In this study, an oxygen free radical analyzer was used to measure oxygen free radical levels. The oxygen free radical analyzer analyzes the amount of oxygen free radicals in the body by measuring urinary malondialdehyde (MDA). To determine factors associated with oxygen free radical levels, multiple regression tests were conducted. Of the participants, 89.6% exhibited normal levels of oxygen free radicals and 10.4% had elevated levels. In this study, the factors that affected oxygen free radical levels were eating habit (&amp;beta; = .20, p =. 003), fatigue (&amp;beta; = .20, p = .004), and detox necessity (&amp;beta; = .18, p = .006). In order to lower oxygen free radical levels of female nursing students, the areas of eating habit, fatigue, and detox must receive increased focus.

Investigation of Blood and Urine Malondialdehyde Levels in Mice Exposed to Silica Dust

Background and Objectives:Occupational exposure to silica dust can lead to biochemical damage. Malondialdehyde (MDA) can be considered as a primary marker for measuring the level of oxidative stress in a living organism. This study was conducted in order to evaluate the level of MDA in blood and urine of mice exposed to silica dust.Material and Methods:In this experimental study, 72 mice (BALB/c) were randomly allocated to five exposed groups and 1 control group. Exposure of mice to pure 99% silica dust was done in closed containers. Blood sampling was performed from the heart of mice and urine sampling fulfilled by insertion into a metabolic cage. The RAOet al. method was used to measure MDA.Results:The highest level of plasma MDA in group 1 in the 4thmonth was 8.4±0.41 nmol/l and the lowest level of MDA was 1.3±0.2 nmol/l in the third sampling in the control group, also the highest amount of urine MDA in the first and second groups and 4 months after exposure was 1.16±0.51 nmol/l, and the lowest in the control group and in the third sampling was 0.48±0.06 nmol/l. A significant difference was found between the levels of MDA in all exposed groups at different times except for the 5thgroup with the lowest concentration (P&lt; 0.05).Conclusion:MDA in blood and urine could be proposed as a good biomarker for the evaluation of biochemical damages caused by silica dust. Measuring MDA is also a simple and inexpensive method that does not require complex equipment and can be used as an early detection test for biochemical damages caused by silica.

Pinitol consumption improves liver health status by reducing oxidative stress and fatty acid accumulation in subjects with non-alcoholic fatty liver disease: A randomized, double-blind, placebo-controlled trial

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent cause of chronic hepatic injury in the world. One of the most important therapeutic strategies for this disease is modulating oxidative stress. This study hypothesized that supplementation of pinitol might exert hepatic protective effects, by modulating oxidative stress in subjects with NAFLD. A randomized, double-blind controlled trial was conducted in 90 subjects with ultrasonography-proven NAFLD, who were randomly assigned to the placebo, low-dose (300 mg/d), or high-dose (500 mg/d) of pinitol for 12 weeks. The outcome measures were liver fat content, liver enzymes, fasting and postprandial lipids, and oxidative stress levels. To understand the underlying mechanism, plasma metabolomic analysis based on a gas chromatography/time-of-flight mass spectrometry and urinary pinitol analysis were also performed. The pinitol group showed significantly lower levels in liver fat content, plasma liver enzymes, fasting/postprandial urinary malondialdehyde levels, and postprandial triglycerides concentrations, but significantly higher in glutathione peroxidase level compared with the placebo group. The metabolomic analysis identified 27 differential metabolites involved in glycine/serine/threonine metabolism, alanine/aspartate/glutamate metabolism, D-glutamine/D-glutamate metabolism, and fatty acid synthesis, implicating the role of pinitol in glutathione-related lipid and energy metabolism. These results suggest that pinitol may exert modulatory effects upon energy and metabolic pathways by reducing oxidative stress and fatty acid accumulation, which can lead to hepatoprotective benefits in NAFLD subjects.

By-products of lithotripsy: Are they related to abdominal fat and wave characteristics?

ObjectivesThis study aimed to evaluate the correlations between by-products of extracorporeal shock wave lithotripsy (ESWL) and some physical parameters such as abdominal fat, energy levels, and shock wave pulses.MethodsA total of 40 patients (20 men and 20 women), aged 37.18 ± 10.64 years, with renal or ureteral stones were recruited. All patients were treated with ESWL, and their abdominal fat was measured using an Omron body fat monitor and the body mass index (BMI). Parameters such as the levels of malondialdehyde (MDA), ketones, and protein in urine were measured before and after ESWL using a Bio Doctor Analyzer. The wave characteristics of the lithotripsy procedure and the wave pulses were determined.ResultsThe mean levels of urinary MDA and ketones showed statistically significant increases in post-ESWL compared with pre-ESWL values. The results showed significant elevations in MDA and ketones in both male and female patients. In addition, there was a significant correlation between MDA/ketones and energy levels and between ketones and BMI in female patients. The analysis also revealed that the shock wave pulse had an insignificant impact on the by-product parameters.ConclusionAn energy level of ≤4 J is recommended for overweight and obese patients undergoing ESWL. In addition, measurement of the post-ESWL MDA urinary level should be performed as a routine test, especially in obese male patients.

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.

Effects of short-term atorvastatin use in patients with calcium stones: A randomized placebo-controlled clinical trial.

PurposeA few experimental and observational studies have reported that atorvastatin prevents calcium oxalate stone formation. Our study is the first to investigate the effect of atorvastatin on 24-hour urinary metabolites, urinary malondialdehyde (U-MDA) (an oxidative stress marker) and urinary neutrophil gelatinase-associated lipocalin (U-NGAL) (a renal tubular injury marker) in patients with calcium stones and hyperoxaluria.Materials and MethodsThis randomized, double-blind, placebo-controlled, parallel-group clinical trial included 32 adults with recurrent calcium stone formation and hyperoxaluria. All participants received a 3-month course of either atorvastatin (20 mg/d) or placebo of an identical shape. Both groups received the usual nutritional care based on the European Association of Urology guidelines.ResultsTwenty-eight participants completed the study. Serum levels of total and low-density lipoprotein cholesterol decreased in the atorvastatin group, and these changes were significantly different between groups (p<0.001). No statistically significant differences were observed between intergroup changes of the 24-hour urinary metabolite analysis, the U-MDA to creatinine ratio and the U-NGAL to creatinine ratio.ConclusionsAtorvastatin administration at a dose of 20 mg/d for 3 months did not affect 24-hour urinary metabolite, U-MDA and U-NGAL levels in recurrent calcium stone formers. However, this study could not disprove the preventive role of atorvastatin in kidney stone formation. Future studies should consider a larger sample size, longer follow-up, different drug doses, and measurements of multiple biomarkers of oxidative stress and tubular injury.

Genistein attenuates renal fibrosis in streptozotocin‑induced diabetic rats

The present study aimed to investigate the antifibrogenic effects of genistein (GEN) on the kidney in streptozotocin (STZ)-induced diabetic rats and to determine the associated mechanisms. Rats were randomized into four groups: Normal control (N), STZ (S), L (STZ + low-dose GEN) and H (STZ + high-dose GEN). After 8 weeks, the fasting blood glucose (FBG) level, the ratio of kidney weight to body weight (renal index), 24-h urine protein, blood urea nitrogen (BUN), serum creatinine (SCr), renal total antioxidant capacity (T-AOC), superoxide dismutase (SOD), lipid peroxidation (LPO), malondialdehyde (MDA) and hydroxyproline (Hyp) contents were measured. The histomorphology and ultrastructure of the kidney were also assessed. In addition, mRNA expression levels of transforming growth factor-β1 (TGF-β1) and protein expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO1), TGF-β1, mothers against decapentaplegic homolog 3 (Smad3), phosphorylated (p)-Smad3 and collagen IV were estimated. Compared with group N, the levels of FBG, renal index, 24-h urine protein, BUN, SCr, LPO, MDA and Hyp were increased, whereas the levels of T-AOC and SOD were decreased in group S. The structure of renal tissue was damaged, and the expression of Nrf2, HO-1 and NQO1 were reduced, whereas the expression of TGF-β1, Smad3, p-Smad3 and collagen IV were increased in group S. Compared with group S, the aforementioned indices were improved in groups L and H. In conclusion, GEN exhibited reno-protective effects in diabetic rats and its mechanisms may be associated with the inhibition of oxidative stress by activating the Nrf2-HO-1/NQO1 pathway, and the alleviation of renal fibrosis by suppressing the TGF-β1/Smad3 pathway.

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

BackgroundOxidative 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. MethodsFifty-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. ResultsResults 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. ConclusionOur 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.

The Effects of Melatonin on the Relationship between Air Pollution Levels and Biomarkers of Oxidative Stress and Platelet Activation in Healthy Young Adults

Urinary free malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) as biomarkers of oxidative stress as well as soluble P-selectin as a biomarker of platelet activation have been associated with air pollution exposure. However, the results have not been consistent across studies. We hypothesize that this inconsistency might be due to modification of circulating melatonin, a free radical scavenger and a key factor in the DNA damage repair system, on MDA and 8-OHdG responses to reactive oxygen species induced by air pollution exposure. Melatonin also regulates PPAR&amp;#947;/FUNDC1/ mitophagy pathways, hence affecting P-selectin level. We conducted a longitudinal study involving 70 healthy young adults living on a hospital campus in Shanghai. Indoor and outdoor PM2.5, O3, and NO2 were monitored throughout the study and combined with time activity pattern to estimate personal air pollution exposure. The results show that a 10% increase of urinary 6-sulfatoxymelatonin (aMT6s, a major metabolite of melatonin and highly correlated with circulating melatonin) was associated with a significant increase in urinary 8-OHdG by 2.4% [95% CI: 1.4%, 3.4%] and a significant decrease in urinary free MDA and soluble P-selectin by -1.5% [-2.4%, -0.6%] and -1.0% [-1.9%, -0.1%], respectively. Compared to unadjusted models (specified in parenthesis), models with urinary aMT6s as an effect modifier showed that 10 µg/m3 in PM2.5 12h personal exposure was associated with a change in urinary 8-OHdG by 11.0% [-2.4%, 24.3%] (unadjusted: -3.8% [-7.4%, -0.2%]), a change in urinary free MDA by 14.0% [2.4%, 25.7%] (unadjusted: -0.3% [-3.4%, 2.8%]), and 10 µg/m3 increase in NO2 12h personal exposure was associated with a change in P-selectin by 5.4% [-10.2%, 21.0%] (unadjusted: -5.3% [-9.5%, -1.1%]). Similar mediation effects were also observed for O3. These findings support the role of melatonin as a mediator for oxidative stress and platelet activation introduced by air pollution exposure.

Effects of Anti-oxidants on Oxidative Stress: Assessing MDA in Urine Samples

This study looked at reducing oxidative stress and free radicals using oral antioxidants. Malondialdehyde (MDA) is widely used as a biomarker for assessing oxidative stress in biomedical fields and in many health problems such as cancer, psychiatry, chronic obstructive pulmonary disease, asthma, or cardiovascular diseases. Lipid peroxidation is a chain phenomenon resulting in the formation of various active compounds that result in cellular damage and another mechanism involved in oxidative stress. Oxidative stress status was determined using the urinary malondialdehyde test. Preliminary conclusion suggests that oxidative stress in the body can be reduced with appropriate oral anti-oxidants. However future research has to determine to what extent the digestive system and the stress hormonal systems can impact the oxidative status.

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.

Effect of a Protein Supplement on the Gut Microbiota of Endurance Athletes: A Randomized, Controlled, Double-Blind Pilot Study.

Nutritional supplements are popular among athletes to improve performance and physical recovery. Protein supplements fulfill this function by improving performance and increasing muscle mass; however, their effect on other organs or systems is less well known. Diet alterations can induce gut microbiota imbalance, with beneficial or deleterious consequences for the host. To test this, we performed a randomized pilot study in cross-country runners whose diets were complemented with a protein supplement (whey isolate and beef hydrolysate) (n = 12) or maltodextrin (control) (n = 12) for 10 weeks. Microbiota, water content, pH, ammonia, and short-chain fatty acids (SCFAs) were analyzed in fecal samples, whereas malondialdehyde levels (oxidative stress marker) were determined in plasma and urine. Fecal pH, water content, ammonia, and SCFA concentrations did not change, indicating that protein supplementation did not increase the presence of these fermentation-derived metabolites. Similarly, it had no impact on plasma or urine malondialdehyde levels; however, it increased the abundance of the Bacteroidetes phylum and decreased the presence of health-related taxa including Roseburia, Blautia, and Bifidobacterium longum. Thus, long-term protein supplementation may have a negative impact on gut microbiota. Further research is needed to establish the impact of protein supplements on gut microbiota.

Effects of Pioglitazone and Irbesartan on Endothelial Dysfunction on Experimentally Streptozotocin-Induced Diabetic Nephropathy in Rats

Background and Aim. Diabetes mellitus is associated with an induction of vascular endothelial dysfunction (VED) that leads to the pathogenesis of diabetic nephropathy (DN). Diabetic nephropathy (DN) is a main cause of end stage renal disease. This study was designed to investigate the protective effects of irbesartan (IRB) and its combination with pioglitazone (PIO) on impaired endothelial dysfunction, oxidative stress, and inflammation beyond blood glucose control in streptozotocin- (STZ-) induced diabetic nephropathy in rats. Materials and Methods. Forty-eight male albino rats were divided equally and randomly into six groups: A (control non- diabetic non-treated) and B (diabetic non-treated) injected intraperitoneally by streptozotocin (65mg/kg) and nicotinamide (110 mg/kg) to induce diabetic nephropathy; C (diabetic treated with IRB (30mg/kg/daily) orally), D (diabetic treated with PIO (30mg/kg/daily) orally), E (diabetic treated with IRB and PIO in doses (30 mg/kg/day and 30 mg/kg/day) orally), and F (diabetic treated with IRB and PIO in doses (5mg/kg/day and 15mg/kg/day, resp.) orally for 12 weeks). Fasting blood glucose, urea, creatinine, albumin in urine levels, IL-6, nitric oxide (NO), and Malondialdehyde peroxidase (MDA) were determined in serum of the different groups at the end of the experiment; renal blood flow and aortic and renal histopathological changes were also evaluated. Results. Administration of irbesartan and pioglitazone to diabetic rats caused significant decrease in levels of urea, creatinine, albumin, serum inflammatory mediators (IL-6 and NO), and oxidative stress markers. The effects of irbesartan and/or pioglitazone were associated with improvement of renal blood flow, and they markedly reduced vascular and renal damage induced by diabetes. Conclusion. The results of the present study support the fact that the combination between irbesartan and pioglitazone was better than monotherapy on endothelial dysfunction and diabetic nephropathy through inhibition of the pro-inflammatory mediators, NO bioavailability, and oxidative stress, which are independent of their glucose-lowering properties. And there was no significant difference between the combination of pioglitazone and irbesartan in large doses and in low doses.

Plasma and Urine Malondialdehyde Levels of Infants with Acute Bronchopneumonia in the Assessment of Oxidative Response

Objective: Acute lower respiratory tract infections are seen as a major public health problem in many developing countries. This study was carried out in order to evaluate plasma and urine malonyldialdehyde (MDA) levels which represents the lipid peroxidation and hence of oxidative stress in infants diagnosed with acute bronchopneumonia which is a cause of high mortality and morbidity in children.Material and methods: This case-control study was carried out at the department of Paediatrics, Ministry of Health Bakirkoy Sadi Konuk Training and Research Hospital in 2005. The patient group comprised of 25 patients who were admitted to the hospital with the diagnosis of acute bronchopneumonia. The control group consisted of 10 healthy children of the same age range who had no pathological findings on physical examination. MDA values of urine and plasma samples were compared between both groups as an oxidative stress indicator.Results: The mean serum MDA value of the patient group was 3.91 ± 1.55 micromol/L and that of the control group was measured as 1.03 ± 0.1micromol/L. The difference was significantly higher (p 0.05).Conclusion: The urine MDA values on the first day of follow-up and the plasma MDA values may be used as a parameter in the diagnosis and following-up treatment of oxidative stress in the infants with acute bronchopneumonia.