Biomarkers Of Systemic Oxidative Stress Research Articles

Comparison of machine learning methods for Predicting 3-Year survival in elderly esophageal squamous cancer patients based on oxidative stress

SummaryBackgroundOxidative stress process plays a key role in aging and cancer; however, currently, there is paucity of machine-learning model studies investigating the relationship between oxidative stress and prognosis of elderly patients with esophageal squamous cancer (ESCC).MethodsThis study included elderly patients with ESCC who underwent curative ESCC resection surgery continuously from January 2013 to December 2020 and were stratified into the training and external validation cohorts. Using Cox stepwise regression analysis based on Akaike information criterion, the relationship between oxidative stress biomarkers and prognosis was explored, and a geriatric ESCC-related oxidative stress score (OSS) was constructed. To construct a predictive model for 3-year overall survival (OS), machine-learning strategies including decision tree (DT), random forest (RF), and support vector machine (SVM) were employed. These machine-learning strategies play a key role in data mining and pattern recognition tasks. Each model was tested in the external validation cohort through 1000 resampling iterations. Validation was conducted using receiver operating characteristic area under the curve (AUC) and calibration plots.ResultsThe training cohort and validation cohort consisted of 340 and 145 patients, respectively. In the training cohort, the 3-year OS rate for patients was 59.2%. We constructed the OSS based on systemic oxidative stress biomarkers using the training cohort. The study found that pathological N stage, pathological T stage, tumor histological type, lymphovascular invasion, CEA, OSS, CA 19 − 9, and the amount of bleeding were the most important factors influencing the 3-year OS. These eight important features were included in training the RF, DT, and SVM and trained on the training cohort and validated cohort, respectively. In the training cohort, the RF model demonstrated the highest predictive performance with an AUC of 0.975 (0.962–0.987), while the DT model is 0.784 (0.739–0.830) and the SVM is 0.879 (0.843–0.916). In the external validation cohort, the RF model again exhibited the highest performance with an AUC of 0.791 (0.717–0.864), compared to the DT model with an AUC of 0.717 (0.640–0.794) and 0.779 (0.702–0.856) in SVM.ConclusionsThe random forest clinical prediction model constructed based on OSS can effectively predict the prognosis of elderly patients with ESCC after curative surgery.

Effects of Different Therapeutic Approaches on Redox Balance in Psoriatic Patients.

Given that oxidative stress represents an important etiological factor in the pathogenesis of psoriasis, the aim of this study was to assess the effects of different therapeutic approaches, methotrexate, secukinumab, and ustekinumab on systemic oxidative stress biomarkers in psoriatic patients. This study involved 78 psoriatic patients, divided into the group treated with methotrexate (23 patients), secukinumab (28 patients), and ustekinumab (27 patients), and 15 healthy controls. Oxidative stress biomarkers (index of lipid peroxidation measured as TBARS, nitrites (NO2-), superoxide anion radical (O2-), and hydrogen peroxide (H2O2)) and antioxidative defense system (superoxide dismutase (SOD) activity, catalase (CAT) activity, and reduced glutathione (GSH)) were determined spectrophotometrically from the blood before the initiation of therapy in 16th, 28th, and 52nd week. O2- and SOD showed the most prominent changes comparing the psoriatic patients and healthy controls. CAT activity was significantly lower in psoriatic patients, and methotrexate induced a further decline in CAT activity. Ustekinumab induced a significant increase in GSH level after 52 weeks of treatment, while methotrexate reduced GSH. All applied therapeutic options induced a reduction in PASI, BSA, DLQI, and EARP. Biological drugs exert more pronounced antioxidant effects compared to methotrexate, which is most clearly observed in the values of O2- and SOD.

Machine learning-based prediction of 5-year survival in elderly NSCLC patients using oxidative stress markers.

Oxidative stress plays a significant role in aging and cancer, yet there is currently a lack of research utilizing machine learning models to examine the relationship between oxidative stress and prognosis in elderly non-small cell lung cancer (NSCLC) patients. This study included elderly NSCLC patients who underwent radical lung cancer resection from January 2012 to April 2018, exploring the relationship between Oxidative Stress Score (OSS) and prognosis. Machine learning techniques, including Decision Trees (DT), Random Forest (RF), and Support Vector Machine (SVM), were employed to develop predictive models for 5-year overall survival (OS). The datasets consisted of 1647 patients in the training set, 705 in the internal validation set, and 516 in the external validation set. An OSS was formulated from six systemic oxidative stress biomarkers, such as albumin, total bilirubin, and blood urea nitrogen, among others. Boruta variable importance analysis identified low OSS as a key indicator of poor prognosis. The OSS was subsequently integrated into the DT, RF, and SVM models for training. These models, optimized through hyperparameter tuning on the training set, were then evaluated on the internal and external validation sets. The RF model demonstrated the highest predictive performance, with an Area Under the Receiver Operating Characteristic Curve (AUC) of 0.794 in the internal validation set, compared to AUCs of 0.711 and 0.760 for the DT and SVM models, respectively. Similarly, in the external validation set, the RF model achieved an AUC of 0.784, outperforming the DT and SVM models, which had AUCs of 0.699 and 0.730, respectively. Calibration plots confirmed the RF model's superior calibration, followed by the SVM model, with the DT model performing the poorest. The OSS-based clinical prediction model, constructed using machine learning methodologies, effectively predicts the prognosis of elderly NSCLC patients post-radical surgery.

Systemic Oxidative Stress Parameters in Skin Cancer Patients and Patients with Benign Lesions

Oxidative stress is caused by an imbalance between the production and subsequent accumulation of reactive oxygen species (ROS) in cells and tissues and the capacity of a biological system to eliminate these reactive substances. Systemic oxidative stress biomarkers in plasma, serum, urine, or red blood cells have been found to be elevated in many diseases, including skin cancer. UV radiation (UVR) induces damage to biomolecules that enter the bloodstream, reinforcing systemic oxidative stress. On the other hand, pre-existing systemic oxidative stress does not supply the skin with the adequate micronutrients and antioxidant resources to ameliorate the skin’s antioxidant defense against UVR. In both scenarios, skin cancer patients are exposed to oxidative conditions. In the case of warts, oxidation is linked to chronic inflammation, while impaired cutaneous antioxidant defense could ineffectively deal with possible oxidative stimuli from viral agents, such as HPV. Therefore, the aim of our study is to evaluate the existing data on systemic oxidative stress in skin diseases such as non-melanoma skin cancer (NMSC), basal-cell carcinoma (BCC), squamous-cell carcinoma (SCC), and melanoma as well as benign lesions such as actinic keratosis (AK), sebaceous keratosis (SK), and warts. Previous studies have demonstrated that patients with NMSC, melanoma, AK, and warts (both genital and non-genital) are subjected to severe oxidative stress, indicated by disturbed antioxidant enzyme levels, accumulated oxidized proteins and lipid products, and, to a lesser extent, lower concentrations of micronutrients. Interestingly, medical history of NMSC or melanoma as well as stage of skin cancer and treatment approach were found to affect systemic oxidative stress parameters. In the case of warts (both genital and non-genital), high oxidative stress levels were also detected, and they were found to be aligned with their recalcitrant character.

Prognostic Value of Redox Status Biomarkers in Patients Presenting with STEMI or Non-STEMI: A Prospective Case-Control Clinical Study.

(1) Background: The aim of our study was to determine the role of oxidative stress (OS) during early evaluation of acute ST-elevated myocardial infarction (STEMI) and non-ST-elevated myocardial infarction (NSTEMI) patients in order to define the role of redox balance in profiling the development of myocardial infarction (MI). (2) Methods: This prospective observational case-control study included 40 consecutive STEMI and 39 NSTEMI patients hospitalized in the coronary care unit of the cardiology clinic at the Kragujevac Clinical Center, Serbia, between 1 January 2016 and 1 January 2017. Blood samples were collected from all patients for measuring cardio-specific enzymes at admission and 12 h after admission to evaluate systemic oxidative stress biomarkers and the activity of antioxidant enzymes. (3) Results: In this study, participants were predominately female (52%), with a mean age of 56.17 ± 1.22 years old in the STEMI group and 69.17 ± 3.65 in the non-STEMI group. According to the Killip classification, the majority of patients (>50%) were at the second and third level. We confirmed the elevation of superoxide anion radicals in the non-STEMI group 6 h after admission in comparison with the STEMI and CTRL groups, but levels had decreased 12 h after admission. Levels of hydrogen peroxide were statistically significantly increased in the NSTEMI group. A positive correlation of superoxide anion radicals and levels of troponin I at admission was observed (r = 0.955; p = 0.045), as well as an inverse correlation between reduced glutathione and levels of NT-pBNP measured 6 h after admission (r = -0.973; p = 0.027). (4) Conclusions: We confirmed that superoxide anion radicals and reduced glutathione observed together with hs-troponin I at admission and NT-pBNP during hospital treatment could be predictors of ST evolution.

115 Effects of Probiotic and Heat-Killed Probiotic Supplementation on Systemic Biomarkers of Oxidative Stress and Inflammation and Fermentative end Products of Adult Cats

Abstract Probiotics and heat-killed probiotics (postbiotic) have been linked with enhancement of the intestinal barrier function and mucosal immunity, anti-inflammatory properties, as well as production of fermentative end-products including short-chain fatty acids (SCFA), which may confer benefits to the gut microbiome and health. This study aimed to evaluate the longitudinal effects of daily supplementation of pro- and post-biotics on oxidative stress biomarkers such as malondialdehyde (MDA) and superoxide dismutase (SOD), inflammatory biomarkers from a panel of 19 cytokines and chemokines, the hormone leptin, as well as the fecal metabolites, such as phenol and indole, SCFA, and ammonia, of adult cats. The study was a complete randomized design with 36 cats divided into 3 treatments (n=12/treatment). Animals were fed a standard extruded commercial diet. The treatments used were control diet + placebo (maltodextrin carrier; CON), control diet + Probiotic (Bifidobacterium animalis subsp. Lactis CECT8145; daily dosage: 109CFU/cat; PRO), and control diet + postbiotic (Heat-killed Bifidobacterium animalis subsp. lactis CECT8145; daily dosage: 109CFU/cat; PST). Test articles were supplied by ADM Biopolis (Valencia, Spain). Longitudinal analyses were performed every 30 days for a total of 90 days. No interaction of day by treatment (P >0.05) was observed for any of the variables evaluated. For fecal metabolites, there was a main effect of treatment for butyrate concentration, PST was greater (P< 0.05) than PRO. It was also observed a main effect of treatment for some cytokines and chemokines, cats on CON had reduced (P< 0.05) GM-CSF, KC, and SDF-1, when compared with PST, PRO, and both PST and PRO respectively. Whilst for RANTES and IL-12(p40), cats on CON had greater concentration (P< 0.05) when compared with cats on PST and PRO, and PST, respectively. Overall, the supplementation of the probiotic and postbiotic showed no detrimental effects on oxidative stress and inflammatory biomarkers, and fermentative end-products in adult cats.

Local and Systemic Oxidative Stress Biomarkers for Male Infertility: The ORION Study.

Infertility problems occur in around 10% of all couples worldwide, with male-factor infertility as the sole contributor in 20–30% of these cases. Oxidative stress (OS) is suggested to be associated with the pathophysiology of male infertility. In spermatozoa, OS can lead to damage to the cell membrane, resulting in disruption of DNA integrity and a decrease in motility. Established biomarkers for OS include free thiols and malondialdehyde (MDA), both representing different components of the reactive species interactome (RSI). This exploratory study aimed to investigate seminal plasma-free thiol and MDA levels in relation to semen parameters as defined by the World Health Organization (WHO) to determine if these markers are adequate to define local OS status. Furthermore, this study investigated if there is a relation between systemic and local OS status by comparing seminal concentrations of free thiol (R-SH, sulfhydryl groups, representing the extracellular redox status) and MDA (lipid peroxidation product) levels to those measured in serum. Free thiol and MDA measurements in both serum and semen plasma were performed in 50 males (18–55 y) of couples seeking fertility treatment. A significant positive correlation was found between seminal plasma-free thiol levels and sperm concentration and progressive motility (r = 0.383, p = 0.008 and r = 0.333, p = 0.022, respectively). In addition, a significant positive correlation was found between MDA levels in seminal plasma and sperm concentration (r = 0.314, p = 0.031). This study supports that seminal plasma-free thiols may be promising as local OS biomarkers. No associations were observed between local and systemic OS biomarker concentrations.

Urinary Biomarkers of Oxidative Stress in Aging: Implications for Prediction of Accelerated Biological Age in Prospective Cohort Studies.

Background Aging is a major risk factor for a range of chronic diseases. Oxidative stress theory of aging has been previously proposed as one of the mechanisms responsible for the age-related decline in organ/tissue function and the development of age-related diseases. Urine contains rich biological information on the health status of every major organ system and can be an important noninvasive source for biomarkers of systemic oxidative stress in aging. Aims The objective of this cross-sectional study was to validate a novel panel of urinary oxidative stress biomarkers. Methods Nucleic acid oxidation adducts and oxidative damage markers of lipids and proteins were assessed in urine samples from nondiabetic and currently nonsmoking subjects (n = 198) across different ages (20 to 89 years old). Urinary parameters and chronological age were correlated then the biological age of enrolled individuals was determined from the urinary oxidative stress markers using the algorithm of Klemera and Doubal. Results Our findings showed that 8-oxo-7,8-deoxyguanosine (8-oxoG), 8-oxo-7,8-dihydroguanosine (8-OHdG), and dityrosine (DTyr) positively correlated with chronological age, while the level of an F2-isoprostane (iPF2α-VI) correlated negatively with age. We found that 8-oxoG, DTyr, and iPF2α-VI were significantly higher among accelerated agers compared to nonaccelerated agers and that a decision tree model could successfully identify accelerated agers with an accuracy of >92%. Discussion. Our results indicate that 8-oxoG and iPF2α-VI levels in the urine reveal biological aging. Conclusion Assessing urinary biomarkers of oxidative stress may be an important approach for the evaluation of biological age by identifying individuals at accelerated risk for the development of age-related diseases.

Systemic oxidative stress biomarkers in patients with vitreomacular traction syndrome.

To evaluate whether the systemic oxidative stress biomarkers increased in patients with vitreomacular traction syndrome (VMT). This study compared 25 patients diagnosed with VMT with 20 healthy controls. As a biomarker of systemic oxidative stress, malondialdehyde (MDA) was measured. Total oxidant status (TOS) and total antioxidant status (TAS) were measured to evaluate the systemic oxidant status. Serum MDA values were significantly higher among the patients (p < 0.001). The ideal cut-off value for MDA was determined to be 22.1µmol/L, with 80% sensitivity and 75% specificity. The between-group differences were not statistically significant for TOS or TAS (p = 0.326 and p = 0.698, respectively). Increased MDA levels suggest that systemic oxidative stress may play a role in VMT.

Exposure to Arsenic in the Air and 15-F2t-Isoprostane in Urine in a Sub-population of Inhabitants of a Copper Smelter Region

Most studies on arsenic toxicity have been conducted among populations exposed to arsenic contained in drinking water. Relatively little research concerns effects of airborne arsenic. The aim of this study was to determine whether there is an association between urinary 15-F2t-isoprostane (u15-F2t-IsoP) levels in relation to renal function (urinary creatinine and N-acetyl-β-d-glucosaminidase––uNAG) and urinary arsenic (uAs) in inhabitants from copper smelter impact zone. The secondary purpose of the analysis was to assess utility of a potential association between uAs and u15-F2t-IsoP as a biomarker of systemic oxidative stress. Urinary 15-F2t-IsoP, NAG, and creatinine were measured in 967 urine samples collected from 649 adult women (51.9 ± 13.2 years old) and 318 adult men (53.8 ± 14.9 years old). Total uAs concentration was measured in 918 samples using HPLC-ICP-MS. Arsenic species, such as inorganic arsenic, methylarsonic acid, dimethylarsinic acid, and arsenobetaine, were measured in urine collected from 255 participants with uAs exceeding the upper norm. Data were analyzed using multivariate linear regression and logistic regression models. In the studied population urinary creatinine was positively associated with uAs. A positive linear correlation (p < 0.0000) between lg(uAs) and u15-F2t-IsoP was found both for normal and elevated uAs. A positive linear correlation was observed also between lg(ΣuAs) and u15-F2t-IsoP (p < 0.0000). In the logistic regression model, after adjustment for confounders, elevated uAs was the only predictor of increased u15-F2t-IsoP (OR = 1.31, 95% CI 1.08–1.59, p < 0.01). Cigarette smoking was associated with renal proximal tubular dysfunction only in people with uNAG concentration above 75th quartile. In the studied population chronically exposed to airborne arsenic, increase in urinary arsenic is associated with renal dysfunction and systemic oxidative stress. Urinary 15-F2t-isoprostane may be useful in the monitoring of health status in populations exposed to airborne arsenic.

Serum Albumin Redox States: More Than Oxidative Stress Biomarker.

Serum albumin is the most abundant circulating protein in mammals including humans. It has three isoforms according to the redox state of the free cysteine residue at position 34, named as mercaptalbumin (reduced albumin), non-mercaptalbumin-1 and -2 (oxidized albumin), respectively. The serum albumin redox state has long been viewed as a biomarker of systemic oxidative stress, as the redox state shifts to a more oxidized state in response to the severity of the pathological condition in various diseases such as liver diseases and renal failures. However, recent ex vivo studies revealed oxidized albumin per se could aggravate the pathological conditions. Furthermore, the possibility of the serum albumin redox state as a sensitive protein nutrition biomarker has also been demonstrated in a series of animal studies. A paradigm shift is thus ongoing in the research field of the serum albumin. This article provides an updated overview of analytical techniques for serum albumin redox state and its association with human health, focusing on recent findings.

Role of endogenous melatonin in pathophysiologic and oxidative stress responses to personal air pollutant exposures in asthmatic children

BackgroundHeightening oxidative stress and inflammation is an important pathophysiological mechanism underlying air pollution health effects in people with asthma. Melatonin can suppress oxidative stress and inflammation in pulmonary and circulatory systems. However, the role of melatonin in the oxidative stress and physiological responses to air pollution exposure has not been examined in children with asthma. MethodsIn this panel study of 43 asthmatic children (5–13 years old), each child had 4 clinic visits with a 2-week interval between two consecutive visits. At each visit, urine samples were collected and subsequently analyzed for 6-sulfatoxymelatonin (aMT6s) as a surrogate of circulating melatonin and for malondialdehyde (MDA) and 8-hydroxy-2′-deoxyguanosine (8-OHdG) as two biomarkers of systemic oxidative stress. At each clinic visit, children were measured for pulmonary function and fractional exhaled nitric oxide (FeNO, a marker of pulmonary inflammation). None of the children reported to have taking melatonin supplementation. Concentrations of indoor and ambient PM2.5 and ozone (O3) were combined with individual time-activity data to calculate personal air pollutant exposures. ResultsWe found that interquartile range increases in urinary MDA and 8-OHdG concentrations were associated with significantly increased urinary aMT6s concentrations by 73.4% (95% CI: 52.6% to 97.0%) and 41.7% (22.8% to 63.4%), respectively. Increases in daily personal exposure to O3 and to PM2.5 were each associated with increased urinary aMT6s concentrations. Increasing urinary aMT6s concentrations were associated with decreased FeNO and resonant frequency, indicating improved airway inflammation and lung elasticity, respectively. ConclusionThe results suggest that systemic oxidative stress heightened by air pollution exposure may stimulate melatonin excretion as a defense mechanism to alleviate the adverse effects.

Negative ions offset cardiorespiratory benefits of PM 2.5 reduction from residential use of negative ion air purifiers

Negative ion air purifiers (NIAPs), as a less costly alternative to the HEPA filtration, have been increasingly deployed in China and potentially elsewhere. While reducing indoor concentrations of fine particulate matter (PM2.5 ), NIAPs generate massive amounts of negative ions that may be of health concern. We performed week-long interventions with NIAPs in the dormitories of 56 healthy college students living in Beijing. In a randomized order, each student underwent a true and a sham NIAP session. Cardiorespiratory outcomes were measured before and after each session. The use of true NIAPs reduced indoor PM2.5 concentrations significantly, while notably increased negative ion levels. Increases in PM2.5 and negative ion (NI) exposure were independently associated with increased urinary concentration of malondialdehyde, a biomarker of systemic oxidative stress, resulting in a null net effect of NIAP on malondialdehyde. Likewise, no significant net effects of NIAPs were observed for other outcomes indicative of lung function, vascular tone, arterial stiffness, and inflammation. Our findings suggest that negative ions, possibly along with their reaction products with the room air constituents, adversely affect health. The downsides do not support the use of NIAPs as a health-based mitigation strategy to reduce PM2.5 exposure, especially in residences with PM2.5 concentrations that are not extremely high.

Malondialdehyde in Nasal Fluid: A Biomarker for Monitoring Asthma Control in Relation to Air Pollution Exposure.

Fine particulate matter (PM2.5) and ozone (O3) may exert oxidative damage in the nose, which is hypothesized to be associated with worsened asthma symptoms. This study, hence, is to explore whether an oxidative stress biomarker, malondialdehyde (MDA) in the nasal fluid, has the potential to aid personalized asthma control. In a panel study of 43 asthmatic children, 5-13 years old, each child was measured 4 times with a 2-week interval between consecutive clinic visits. At each visit, nasal fluid and urine samples were collected, and fractional exhaled nitric oxide (FeNO) was measured as a biomarker of pulmonary inflammation. In addition to nasal MDA, urinary MDA and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were measured as biomarkers of systemic oxidative stress. We also assessed asthma symptoms using the Childhood Asthma-Control Test (C-ACT). We found that interquartile range (IQR) increases in 24 h average personal PM2.5 exposure (22.2-33.5 μg/m3), estimated 0 to 5 days prior to a clinic visit, were associated with increased nasal MDA concentrations by 38.6-54.9%. Similarly, IQR increases in 24 h average personal O3 exposure (7.7-8.2 ppb) estimated 2 to 4 days prior were associated with increased nasal MDA by 22.1-69.4%. Only increased PM2.5 exposure was associated with increased FeNO. Increased nasal MDA concentration was associated with decreased total and individual C-ACT scores, indicating worsening of asthma symptoms. However, no significant associations were observed between urinary MDA or 8-OHdG and C-ACT scores. The results confirm that oxidative stress plays an important role in linking air pollution exposure and adverse respiratory health effects. These findings support that MDA in the nasal fluid may serve as a useful biomarker for monitoring asthma status, especially in relation to PM2.5 and O3 exposures, two known risk factors of asthma exacerbation.

Influence of skin melanisation and ultraviolet radiation on biomarkers of systemic oxidative stress

Skin melanisation ranges widely across human populations. Melanin has antioxidant properties and also acts as a filter to solar ultraviolet radiation (UVR) incident upon the skin. In this study we firstly examined whether melanin level might influence baseline levels of systemic oxidative stress, in 65 humans in vivo from the same geographical area ranging from the lightest to darkest skin type (phototype I-VI). This was examined in winter-time (latitude 53.5°N). Remarkably, we found that urinary biomarkers of oxidatively-generated DNA damage (8-oxodG) and RNA damage (8-oxoGuo) were significantly correlated with skin lightness (L*), such that 14–15% of the variation in their baseline levels could be explained by skin colour. Next we exposed 15 humans at the extremes of skin melanisation to a simulated summer-time exposure of solar UVR (95% UVA, 5% UVB; dose standardised to sunburn threshold), following which they provided a sample of every urine void over the next five days. We found that UVR induced a small but significant increase in urinary 8-oxodG and 8-oxoGuo, with differing kinetics between skin types. Thus greater melanisation is associated with protection against systemic oxidative stress, which may reflect melanin's antioxidant properties, and solar UVR exposure also influences systemic oxidative stress levels in humans. These novel findings may have profound implications for human physiology and health.

The effect of conservative oxygen therapy on systemic biomarkers of oxidative stress in critically ill patients

BackgroundSupplemental oxygen is delivered to critically ill patients who require mechanical ventilation. Oxidative stress is a potential complication of oxygen therapy, resulting in damage to essential biomolecules such as proteins, lipids, and nucleic acids. Whether plasma levels of oxidative stress biomarkers vary based on how liberally oxygen therapy is applied during mechanical ventilation is unknown. MethodsWe carried out an oxidative stress substudy nested within a large multi-centre randomized controlled trial in which critically ill adults were randomized to receive either conservative oxygen therapy or standard oxygen therapy. Blood samples were collected at enrolment, and daily thereafter for up to three days. The antioxidant ascorbate (vitamin C) was assessed using HPLC with electrochemical detection and protein oxidation using a sensitive protein carbonyl ELISA. We also assessed whether critically ill patients with different disease states exhibited varying levels of oxidative stress biomarkers. ResultsA total of 125 patients were included. Mean ascorbate concentrations decreased over time (from 25 ± 9 μmol/L to 14 ± 2 μmol/L, p < 0.001), however, there was no significant difference between the conservative oxygen group and standard care (p = 0.2), despite a significantly lower partial pressure of oxygen (PaO2) in the conservative oxygen group (p = 0.03). Protein carbonyl concentrations increased over time (from 208 ± 30 μmol/L to 249 ± 29 μmol/L; p = 0.016), however, there was no significant difference between the conservative and standard oxygen groups (p = 0.3). Patients with sepsis had significantly higher protein carbonyl concentrations than the other critically ill patients (293 ± 92 μmol/L vs 184 ± 24 μmol/L, p = 0.03). Within the septic subgroup, there were no significant differences in protein carbonyl concentrations between the two interventions (p = 0.4). ConclusionsConservative oxygen therapy does not alter systemic markers of oxidative stress in critically ill ventilated patients compared with standard oxygen therapy. Patients with sepsis exhibited elevated protein carbonyls compared with the other critically ill patients implying increased oxidative stress in this patient subgroup.

Increased systemic and peritoneal oxidative stress biomarkers in endometriosis are not related to retrograde menstruation

ABSTRACTObjetives: The goal of this study was to determine if systemic and peritoneal oxidative stress biomarkers are related to each other and to retrograde menstruation in endometriosis.Methods: Plasma and peritoneal fluid oxidative stress biomarkers and hemoglobin and erythrocytes in peritoneal fluid as retrograde menstruation indicators, were measured in 28 patients with endometriosis and 23 without endometriosis.Results: In the peritoneal fluid, carbonyls and lipohydroperoxides, indicative of protein and lipid oxidative damage, were higher in endometriosis group (21%, p = 0.016 and 46%, p = 0.009, respectively). However, these biomarkers were not different in the blood plasma of both groups, and only protein dityrosine, was increased in the plasma of endometriosis group (31%, p = 0.04). The peritoneal fluid hemoglobin content was not higher in the endometriosis group, nor related to carbonyls and lipohydroperoxides. Additionally, the peritoneal fluid oxidative biomarkers were not correlated with the blood plasma ones, and only malondialdehyde, and ischemia-modified albumin were almost two times higher in peritoneal fluid.Discussion: Our results show a peritoneal and systemic oxidative stress biomarkers increase in endometriosis, but not related to each other, and do not support the hypothesis of an increase in hemoglobin-iron supply towards the peritoneal cavity that causes oxidative damage.

Protocol for a feasibility randomised controlled trial of targeted oxygen therapy in mechanically ventilated critically ill patients

IntroductionOxygen is the most commonly administered drug to mechanically ventilated critically ill adults, yet little is known about the optimum oxygen saturation (SpO2) target for these patients; the current standard...

Thiol-disulfide homeostasis in breast cancer patients.

The aim of our study is to assess thiol-disulfide homeostasis (TDH), which is a biomarker of systemic oxidative stress, in breast cancer patients. Thirty-seven breast cancer patients and 31 age-matched healthy volunteers were enrolled in this study. Serum native thiol, disulfide, and total thiol levels and disulfide/native thiol, disulfide/total thiol, and native thiol/total thiol ratios were analyzed using a novel colorimetric method. Serum native thiol level was statistically significantly lower in breast cancer patients (350.39 ± 7.15) than in healthy controls (380.60 ± 7.35) (P = 0.008). Serum disulfide level was statistically significantly higher in breast cancer patients (24.96 ± 0.85) than in healthy controls (19.25 ± 1.34) (P = 0.002). To our knowledge, this study is the first study in the literature that investigated TDH in breast cancer patients. We have concluded that an alteration in TDH due to oxidative stress is likely to have a role in the pathogenesis of breast cancer.

İdiopatik ani işitme kaybı olan hastaların tiyol/disülfit homeostazisi üzerine hiperbarik oksijen tedavisinin etkisi

Introduction: Idiopathic sudden sensorineural hearing loss (ISSNHL) is an otologic emergency that can lead to loss of function in one of the most important human senses. Recently, hyperbaric oxygen therapy (HBOT) has gained popularity with pharmacotherapy in ISSNHL. This study aimed to determine changes induced in thiol/disulfide homeostasis (TDH, a new biomarker of systemic oxidative stress) by pharmacotherapy and HBOT in patients with ISSNHL.Methods: This prospective study analyzed the albumin, total thiol, native thiol, and disulfide levels and disulfide-native thiol, disulfide-total thiol, and native thiol-total thiol ratios before and after HBOT with standardizing pharmacotherapy using a new colorimetric method in patients with ISSNHL.Results: 41 patients with ISSNHL including 14 (34.1%) women and 27 (65.9%) men participated in the study. The mean age of the patients was 48.02 ± 13.10 years. Of them, 24 (58.5%) had hearing loss in the right ear and 17 (41.5%) had hearing loss in the left ear. There was a statistically significant decrease in the albumin (p&amp;lt;0.001), total thiol (p&amp;lt;0.001), native thiol (p&amp;lt;0.001), and disulfide (p&amp;lt;0.001) levels after treatment compared to baseline. There was no statistically significant difference in the disulfide-native thiol (p=0.148), disulfide-total thiol (p=0.172), and native thiol-total thiol (p=0.169) ratios after treatment compared to baseline. Conclusion: Consequently, this study demonstrated that the thiol-disulphide balance tended to shift towards the oxidative side after HBOT and pharmacotherapy compared to baseline in patients with ISSNHL and that patients with high oxidation level after treatment had better treatment response.