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Redox Imbalance in CD4+ T Cells of Relapsing-Remitting Multiple Sclerosis Patients.
Tavassolifar, MJ, Moghadasi, AN, Esmaeili, B, Sadatpour, O, Vodjgani, M, Izad, M
Oxidative medicine and cellular longevity. 2020;:8860813
Abstract
As a prevalent autoimmune disease of the central nervous system in young adults, multiple sclerosis (MS) is mediated by T cells, particularly CD4+ subsets. Given the evidence that the perturbation in reactive oxygen species (ROS) production has a pivotal role in the onset and progression of MS, its regulation through the antioxidant molecules is too important. Here, we investigated the level of the redox system components in lymphocytes and CD4+ T cells of MS patients. The study was performed on relapsing-remitting MS (RRMS) patients (n = 29) and age- and sex-matched healthy controls (n = 15). Peripheral blood mononuclear cells (PBMCs) were cultured and stimulated by anti-CD3/CD28. The level of ROS, anion superoxide (O2 -), and L-𝛾-glutamyl-Lcysteinylglycine (GSH) was measured by flow cytometry in lymphocytes/CD4+ T cells. The gene expression level of gp91phox, catalase, superoxide dismutase 1/2 (SOD), and nuclear factor-E2-related factor (Nrf2) was also measured by real-time PCR. We found that lymphocytes/CD4+ T cells of RRMS patients at the relapse phase significantly produced higher levels of ROS and O2 - compared to patients at the remission phase (P value < 0.001) and healthy controls (P value < 0.001 and P value < 0.05, respectively). Interestingly, the gene expression level of gp91phox, known as the catalytic subunit of the NADPH oxidase, significantly increased in MS patients at the relapse phase (P value < 0.05). Furthermore, the catalase expression augmented in patients at the acute phase (P value < 0.05), while an increased expression of SOD1 and Nrf2 was found in RRMS patients at relapse and remission phases (P value < 0.05). The increased production of ROS in CD4+ T cells of RRMS patients highlights the importance of amplifying antioxidant components as an efficient approach to ameliorate disease activity in MS patients.
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Strong Associations Exist among Oxidative Stress and Antioxidant Biomarkers in the Circulating, Cellular and Urinary Anatomical Compartments in Guatemalan Children from the Western Highlands.
Soto-Méndez, MJ, Aguilera, CM, Mesa, MD, Campaña-Martín, L, Martín-Laguna, V, Solomons, NW, Schümann, K, Gil, Á
PloS one. 2016;(1):e0146921
Abstract
BACKGROUND A series of antioxidant enzymes and non-enzymatic compounds act to protect cells from uncontrolled propagation of free radicals. It is poorly understood, though, to what extent and how their interaction is harmonized. OBJECTIVES To explore associative interactions among a battery of urinary and blood biomarkers of oxidative stress and enzymatic and non-enzymatic markers of the antioxidant defense system in children from low income households. METHODS For this cross-sectional descriptive study, urine, red cells, and plasma were sampled in 82 preschool children attending three daycare centers in Quetzaltenango Guatemala. The urinary oxidative stress biomarkers studied were F2-isoprostanes and 8-hydroxy-deoxy-guanosine. Red cell enzyme activities measured were: catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase. Circulating non-enzymatic antioxidants selected were: retinol, tocopherols, β-carotene and coenzymes Q9 and Q10. RESULTS In a Spearman rank-order correlation hemi-matrix, of 55 paired combinations of the 11 biomarkers, 28 (51%) were significantly correlated among each other (p ≤ 0.05), with the strongest association being retinol and tocopherols (r = 0.697, p<0.001), and 4 associations (9%) showed a trend (p> 0.5 to ≤ 0.10). F2-isoprostanes showed the greatest number of cross-associations, having significant interactions with 8 of the 10 remaining biomarkers. Goodness-of-fit modeling improved or maintained the r value for 24 of the significant interactions and for one of the 5 borderline associations. Multiple regression backward stepwise analysis indicated that plasma retinol, β-carotene and coenzyme Q10 were independent predictors of urinary F2-isoprostanes. CONCLUSION Numerous significant associations resulted among biomarkers of oxidation and responders to oxidation. Interesting findings were the apparent patterns of harmonious interactions among the elements of the oxidation-antioxidation systems in this population.
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[Antioxidants in erythrocytes in aging and dementia].
Biomeditsinskaia khimiia. 2013;(4):443-51
Abstract
Age of patients and brain oxidative stress may contribute to pathogenesis of Alzheimer's disease (AD). Erythrocytes (red blood cells, RBC) are considered as passive "reporter cells" for the oxidative status of the whole organism and are not well studied in AD. The aim of this work was to assess whether the antioxidant status of RBC changes in aging and AD. Blood was taken from AD and non-Alzheimer's dementia patients, aged-matched and younger controls. In vivo antioxidant status was assessed in each of the study subjects by measuring RBC levels of H202, organic hydroperoxides, glutathione (GSH) and glutathione disulfide (GSSG), activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione S-transferase, and glucose-6-phosphate dehydrogenase. In both aging and dementia, oxidative stress in RBC was shown to increase and to be expressed in elevated concentrations of H202 and organic hydroperoxides, decreased the GSH/GSSG ratio and glutathione S-transferase activity. Decreased glutathione peroxidase activity in RBC may be considered as a new peripheral marker for Alzheimer's disease while alterations of other parameters of oxidative stress reflect age-related events.
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Reduced antioxidant capacities in platelets from patients with autoimmune thrombocytopenia purpura (ITP).
Kamhieh-Milz, J, Bal, G, Sterzer, V, Kamhieh-Milz, S, Arbach, O, Salama, A
Platelets. 2012;(3):184-94
Abstract
Autoimmune thrombocytopenic purpura (ITP) is characterized by an abnormally low platelet count and bleeding risks. The exact triggering event remains elusive. Oxidative stress may play a role in several autoimmune diseases. A direct link between platelets in ITP and oxidative stress has not yet been addressed. The intracellular platelet antioxidant capacity (AOC) in ITP patients in the active phase (n = 24) and remission (n = 12), and 44 healthy controls were analysed with 2',7'-dichlorodihydrofluorescein diacetate, and in combination with hydrogen peroxide. Enzyme activities (EA) of serum glutathione peroxidase (GPx), glutathione reductase (GRed) and catalase (CAT) were investigated colourimetrically in patients and controls. The AOC of ITP patients in the active phase was drastically reduced, with significantly high mean fluorescence intensity values. Higher GPx activity was observed in both active phase and remission in comparison to healthy controls (p < 0.001), with greater activity observed in active ITP than remission (p = 0.001). However, GRed EA was not elevated indicating that reduced glutathione (GSH) is not comparably recovered as consumed, leading to a decreased bioavailability of GSH and increased oxidative stress. These results suggest that oxidative stress is implicated in active ITP and may play a crucial role in its pathophysiology.
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Enzymatic regulation of glucose disposal in human skeletal muscle after a high-fat, low-carbohydrate diet.
Pehleman, TL, Peters, SJ, Heigenhauser, GJ, Spriet, LL
Journal of applied physiology (Bethesda, Md. : 1985). 2005;(1):100-7
Abstract
Whole body glucose disposal and skeletal muscle hexokinase, glycogen synthase (GS), pyruvate dehydrogenase (PDH), and PDH kinase (PDK) activities were measured in aerobically trained men after a standardized control diet (Con; 51% carbohydrate, 29% fat, and 20% protein of total energy intake) and a 56-h eucaloric, high-fat, low-carbohydrate diet (HF/LC; 5% carbohydrate, 73% fat, and 22% protein). An oral glucose tolerance test (OGTT; 1 g/kg) was administered after the Con and HF/LC diets with vastus lateralis muscle biopsies sampled pre-OGTT and 75 min after ingestion of the oral glucose load. The 90-min area under the blood glucose and plasma insulin concentration vs. time curves increased by 2-fold and 1.25-fold, respectively, after the HF/LC diet. The pre-OGTT fraction of GS in its active form and the maximal activity of hexokinase were not affected by the HF/LC diet. However, the HF/LC diet increased PDK activity (0.19 +/- 0.05 vs. 0.08 +/- 0.02 min(-1)) and decreased PDH activation (0.38 +/- 0.08 vs. 0.79 +/- 0.10 mmol acetyl-CoA.kg wet muscle(-1).min(-1)) before the OGTT vs. Con. During the OGTT, GS and PDH activation increased by the same magnitude in both diets, such that PDH activation remained lower during the HF/LC OGTT (0.60 +/- 0.11 vs. 1.04 +/- 0.09 mmol acetyl-CoA.kg(-1).min(-1)). These data demonstrate that the decreased glucose disposal during the OGTT after the 56-h HF/LC diet was in part related to decreased oxidative carbohydrate disposal in skeletal muscle and not to decreased glycogen storage. The rapid increase in PDK activity during the HF/LC diet appeared to account for the reduced potential for oxidative carbohydrate disposal.
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Relationship between 5-fluorouracil disposition, toxicity and dihydropyrimidine dehydrogenase activity in cancer patients.
Di Paolo, A, Danesi, R, Falcone, A, Cionini, L, Vannozzi, F, Masi, G, Allegrini, G, Mini, E, Bocci, G, Conte, PF, et al
Annals of oncology : official journal of the European Society for Medical Oncology. 2001;(9):1301-6
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Abstract
BACKGROUND Previous work demonstrated that 5-fluorouracil (5-FU) metabolism is a critical factor for treatment tolerability. In order to study the predictivity of pharmacokinetics with respect to the occurrence of 5-FU toxicity, this study investigates the relationship between the pharmacokinetics of 5-FU and its metabolite 5-fluoro-5,6-dihydrouracil (5-FDHU), dihydropyrimidine dehydrogenase (DPD) activity in peripheral blood mononuclear cells (PBMNC) and treatment tolerability. PATIENTS AND METHODS Pharmacokinetics and metabolism of 5-FU and activity of DPD in PBMNC were examined in 110 colorectal cancer patients given adjuvant 5-FU 370 mg/m2 plus L-folinic acid 100 mg/m2 for five days every four weeks. Drug levels were examined by HPLC. while toxicities were graded according to WHO criteria. RESULTS DPD activity in patients with mild toxicities (WHO grade < or = 1) was 197.22 < or = 11.34 pmol of 5-FDHU/min/ mg of protein, while in five patients with grade 3-4 gastrointestinal toxicity, DPD ranged from low to normal values (range 31.12-182.37 pmol/min/mg of protein). In these patients. 5-FU clearance (CL) was lower (range 14.12-25.17 l/h/m2), and the area under the curve (AUC) was higher (range 14.70-26.20 h x microg/ml) than those observed in 84 patients with mild toxicities (CL, 56.30 +/- 3.60 l/h/M2; AUC, 7.91 +/- 0.44 h x microg/ml). The severity of adverse events was associated with increased 5-FU/5-FDHU AUC ratio and reduced 5-FU CL, while 5-FU and 5-FDHU pharmacokinetics were not related to DPD activity. CONCLUSION This study shows that DPD activity in PBMNC is unrelated to 5-FU/5-FDHU disposition and patients with severe toxicity display marked pharmacokinetic alterations while a reduction of DPD activity may not occur.
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Effect of recombinant human erythropoietin administration on lipid peroxidation and antioxidant enzyme(s) activities in preterm infants.
Akisu, M, Tuzun, S, Arslanoglu, S, Yalaz, M, Kultursay, N
Acta medica Okayama. 2001;(6):357-62
Abstract
In the present investigation, we studied the effect of recombinant human erythropoietin (r-HuEPO) on serum malondialdehyde (MDA) as an index of lipid peroxidation, related to iron-catalyzed free radical reaction and erythrocyte superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities in very-low-birth weight (VLBW) infants. Forty premature infants, at gestational ages were less than 33 weeks and birthweights were less than 1,500 g, were enrolled in the study. The study population was randomly divided into 2 groups. Twenty infants in Group 1 (treatment group) were given r-HuEPO, and 20 infants in Group 2 served as the control. r-HuEPO treatment (750 U/kg a week) was initiated on the 10th day of life and continued for 6 weeks. Preterm infants given erythrocyte transfusions during the study were excluded from the results. Serum ferritin and MDA levels, and erythrocyte superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities were analyzed at the end of the first week of life (at the beginning of the study). Subsequently, serum ferritin, and MDA levels were measured at the end of the 3rd and the 6th week. SOD, CAT, and GPX activities in the hemolysate were analyzed at the end of the 4th week. Six infants in the control group and 1 infant in the r-HuEPO group received transfusions through the end of the study, and these infants were excluded from the results. Significantly decreased serum ferritin concentrations were found in the r-HuEPO group compared to those in the control group both at the end of the 3rd and the 6th week (P < 0.05, and P < 0.01, respectively). In addition, serum MDA levels were also significantly reduced in Group 1 compared to control both at the end of the 3rd and the 6th week (P < 0.01 and P < 0.05, respectively). A good correlation was found between serum MDA and ferritin levels in Group 1. When the 2 groups were compared with respect to activities of SOD, CAT, and GPX at the end of the 4th week, no differences were observed. Our findings in this study show that administration of r-HuEPO significantly decreases lipid peroxidation, but does not affect erythrocyte antioxidant enzyme(s) activities in preterm infants. The mechanism responsible for the r-HuEPO-induced decrease in lipid peroxidation may concern inhibition to iron-catalyzed free radical reactions.
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Modulation of fluorouracil tissue pharmacokinetics by eniluracil: in-vivo imaging of drug action.
Saleem, A, Yap, J, Osman, S, Brady, F, Suttle, B, Lucas, SV, Jones, T, Price, PM, Aboagye, EO
Lancet (London, England). 2000;(9221):2125-31
Abstract
BACKGROUND Fluorouracil is widely used for chemotherapy of gastrointestinal cancer, but response rates are poor. Eniluracil is being developed as an inactivator of dihydropyrimidine dehydrogenase, the enzyme that brings about first-pass degradation of fluorouracil. We studied the mechanism of action of eniluracil by measuring with positron emission tomography (PET) the effect of eniluracil on tumour and normal-tissue pharmacokinetics of fluorine-18-labelled fluorouracil. METHODS Six patients with advanced gastrointestinal cancers were studied. PET scanning was done after injection of oxygen-15-labelled water to assess tissue blood flow, followed by 1 mg/m2 18F-fluorouracil. We compared the pharmacokinetics of 18F-fluorouracil when the patients had not received eniluracil, during a 4-day course of oral eniluracil, and during a 28-day course of oral fluorouracil plus eniluracil. FINDINGS In eniluracil-naïve patients, 18F-fluorouracil localised more strongly (mean 0.0234% [SE 0.0019] of injected activity per mL tissue at 11 min) in liver than in tumours (0.0032% [0.0004]). There was substantial inhibition, after eniluracil administration, of radiotracer uptake and retention in normal liver (mean area under the time versus radioactivity curve 0.927 [SE 0.086] vs 1.857 [0.169] m2 mL(-1) s) and kidneys (1.096 [0.048] vs 5.043 [0.915] m2 mL(-1) s). There was also an increase in plasma uracil and unmetabolised 18F-fluorouracil and an increase in the radiotracer half-life in tumours (2.3 h to >4.0 h). INTERPRETATION Two events strongly suggested increased exposure of 18F-fluorouracil and its anabolites in the tumours, consistent with the inactivation of dihydropyrimidine dehydrogenase: a selective decrease in radiotracer exposure in normal liver and kidneys compared with tumours; and an increase in radiotracer half-life in tumours.
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Pharmacokinetics and bioequivalence of a combined oral formulation of eniluracil, an inactivator of dihydropyrimidine dehydrogenase, and 5-fluorouracil in patients with advanced solid malignancies.
Ochoa, L, Hurwitz, HI, Wilding, G, Cohen, D, Thomas, JP, Schwartz, G, Monroe, P, Petros, WP, Ertel, VP, Hsieh, A, et al
Annals of oncology : official journal of the European Society for Medical Oncology. 2000;(10):1313-22
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Abstract
BACKGROUND This study was performed to evaluate the pharmacokinetics, bioequivalence, and feasibility of a combined oral formulation of 5-flurouracil (5-FU) and eniluracil (Glaxo Wellcome Inc., Research Triangle Park, North Carolina), an inactivator of dihydropyrimidine dehydrogenase (DPD). The rationale for developing a combined eniluracil/5-FU formulation oral dosing form is to simplify treatment with these agents, which has been performed using separate dosing forms, and decrease the probability of severe toxicity and/or suboptimal therapeutic results caused by inadvertently high or conversely insufficient 5-FU dosing. PATIENTS AND METHODS The trial was a randomized, three-way crossover bioequivalence study of three oral dosing forms of eniluracil/5-FU tablets in adults with solid malignancies. Each period consisted of two days of treatment and a five- to seven-day washout phase. Eniluracil at a dose of 20 mg, which results in maximal DPD inactivation, was administered twice daily on the first day and in the evening on the second day of each of the three treatments. On the morning of the second day, all patients received a total eniluracil dose of 20 mg orally and a total 5-FU dose of 2 mg orally as either separate tablets (treatment A) or combined eniluracil/5-FU tablets in two different strengths (2 tablets of eniluracil/5-FU at a strength (mg/mg) of 10/1 (treatment B) or 8 tablets at a strength of 2.5/0.25 (treatment C)). The pharmacokinetics of plasma 5-FU, eniluracil, and uracil, and the urinary excretion of eniluracil, 5-FU, uracil, and alpha-fluoro-beta-alanine (FBAL), were studied. To determine the bioequivalence of the combined eniluracil/5-FU dosing forms compared to the separate tablets, an analysis of variance on pharmacokinetic parameters reflecting eniluracil and 5-FU exposure was performed. RESULTS Thirty-nine patients with advanced solid malignancies had complete pharmacokinetic studies performed during treatments A, B, and C. The pharmacokinetics of eniluracil and 5-FU were similar among the three types of treatment. Both strengths of the combined eniluracil/5-FU dosing form and the separate dosing forms were bioequivalent. Mean values for terminal half-life, systemic clearance, and apparent volume of distribution for oral 5-FU during treatments A/B/C were 5.5/5.6/5.6 hours, 6.6/6.6/6.5 liters/hour, and 50.7/51.5/50.0 liters, respectively. The intersubject coefficient of variation for pharmacokinetic variables reflecting 5-FU exposure and clearance in treatments ranged from 23% to 33%. The urinary excretion of unchanged 5-FU over 24 hours following treatments A, B, and C averaged 52.2%, 56.1%, and 50.8'%, of the administered dose of 5-FU, respectively. Parameters reflecting DPD inhibition, including plasma uracil and urinary FBAL excretion following treatments A, B, and C were similar. Toxicity was generally mild and similar following all three types of treatments. CONCLUSIONS The pharmacokinetics of 5-FU and eniluracil were similar and met bioequivalence criteria following treatment with the separate oral formulations of 5-FU and eniluracil and two strengths of the combined formulation. The availability of a combined eniluracil/5-FU oral dosing form will likely simplify dosing and decrease the probability of severe toxicity or suboptimal therapeutic results caused by an inadvertent 5-FU overdose or insufficient 5-FU dosing in the case of separate oral formulations, thereby enhancing the overall feasibility and 0therapeutic index of oral 5-FU therapy.