Montserrat Giralt

Oxidative Stress-Related Markers and Langerhans Cells in a Hairless Rat Model Exposed to UV Radiation

Biomarkers related to the oxidative stress in blood and epidermis and the number of Langerhans cells were determined in hairless rats after acute irradiation with 1.54, 1.93, or 2.41 J/cm2 of ultraviolet (UV) light and chronic exposure to 13 suberythemal UV doses of 1.1 J/cm2 for 2 mo. After acute UV irradiation, in epidermis, the thiobarbituric acid-reactive substances (TBARS) content increased at the highest UV dose, whereas the activities of glutathione S-transferase and catalase rose and the oxidized glutathione (GSSG) content diminished at all UV doses. In erythrocytes, glutathione S-transferase activity increased at the two lowest UV doses, glutathione peroxidase activity rose at all UV doses, and catalase activity increased after the highest UV dose. In plasma, the TBARS content and the reduced glutathione (GSH)/GSSG ratio increased at the highest UV dose; the number of Langerhans cells decreased at all UV doses. Linear Pearson correlation analysis revealed many relationships between different biomarkers, and multiple linear regression analysis indicated that the number of Langerhans cells was predicted by epidermal GSSG and catalase (R 2 = .64) and by erythrocytic glutathione peroxidase and GSSG (R 2 = .72). After suberythemal UV radiation, in epidermis, the GST activity and the content of GSH and GSSG increased; in erythrocytes, the GST activity decreased and the GSH/GSSG ratio increased. Thus, the hairless rat appears to be a useful model for studying the oxidative stress-related mechanisms after UV radiation, which are involved in the loss of the immune capacity mediated by Langerhans cells, even at suberythemal doses. This study was conducted at the School of Medicine, Rovira i Virgili University, Reus, Spain. This work was supported by a Research and Development grant (SAF-99-0048) from the Spanish Ministry of Health and Social Security and cosponsored by Novartis CH (Spain). We thank Prof. J. Fernández of the School of Medicine (Reus) for his help with the statistical analyses.

Melatonin reduces oxidative stress in erythrocytes and plasma of senescence‐accelerated mice

Abstract:  It has been suggested that oxidative stress is a feature of aging. The goal of the present study was to assess the oxidant effects related to aging and the protective role of exogenous melatonin in senescence‐accelerated mice (SAMP8). Two groups of SAMP8 mice (males and females) were compared with their respective control groups of SAMR1 mice (senescence‐resistant inbred strain) to determine their oxidative status without melatonin treatment. Four other groups of the same characteristics were treated with melatonin (10 mg/kg/day) in their drinking water. The melatonin concentration in the feeding bottles was titrated according to water consumption and body weight (i.e. 0.06 mg/mL for 30 g of body weight and 5 mL/day of water consumption). The treatment began when animals were 1‐month old and continued for 9 months. When mice were 10‐month old, they were anesthetized and blood was obtained. Plasma and erythrocytes were processed to examine oxidative stress markers: reduced glutathione (GSH), oxidized glutathione (GSSG), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), glutathione S‐transferase (GST), thiobarbituric acid reactive substances (TBARS), and hemolysis. The results showed greater oxidative stress in SAMP8 than in SAMR1, largely because of a decrease in GSH levels and to an increase in GSSG and TBARS with the subsequent induction of the antioxidant enzymes GPX and GR. Melatonin, as an antioxidant molecule, improved the glutathione‐related parameters, prevented the induction of GPX in senescent groups, and promoted a decrease in SOD and TBARS in almost all the groups.

Effect of n-3 PUFA supplementation at different EPA:DHA ratios on the spontaneously hypertensive obese rat model of the metabolic syndrome

The increasing incidence of the metabolic syndrome (MetS), a combination of risk factors before the onset of CVD and type 2 diabetes, encourages studies on the role of functional food components such as long-chain n-3 PUFA as preventive agents. In the present study, we explore the effect of EPA and DHA supplementation in different proportions on spontaneously hypertensive obese (SHROB) rats, a model for the MetS in a prediabetic state with mild oxidative stress. SHROB rats were randomised into four groups (n 7), each supplemented with EPA/DHA at ratios of 1:1, 2:1 and 1:2, or soyabean oil as the control for 13 weeks. The results showed that in all the proportions tested, EPA/DHA supplementation significantly lowered total and LDL-cholesterol concentrations, compared with those of the control group. EPA/DHA supplementation at the ratios of 1:1 and 2:1 significantly decreased inflammation (C-reactive protein levels) and lowered oxidative stress (decreased excretion of urinary isoprostanes), mainly at the ratio of 1:2. The activity of antioxidant enzymes increased in erythrocytes, abdominal fat and kidneys, with magnitudes depending on the EPA:DHA ratio. PUFA mixtures from fish affected different MetS markers of CVD risk factors in SHROB rats, depending on the ratios of EPA/DHA supplementation. The activation of endogenous defence systems may be related to the reduction of inflammation and oxidative stress.

Polypodium leucotomos extract inhibits glutathione oxidation and prevents Langerhans cell depletion induced by UVB/UVA radiation in a hairless rat model.

Abstract:  In this report, we have addressed the effect of oral administration of a hydrophilic extract of the fern Polypodium leucotomos (PL) on the deleterious effects of ultraviolet radiation (UVR) on the levels of epidermal and plasmatic antioxidants in hairless rats. We have found that pretreatment with PL effectively reduced glutathione oxidation in both blood and epidermis, suggesting a potent systemic antioxidant effect. In addition, PL inhibited UVR‐mediated Langerhans cell (LC) depletion. Our results demonstrate the efficacy of PL as an oral antioxidant and photoimmunoprotective agent and support its employment as a complement to topical sunscreens.

Evaluation of oxidative stress biomarkers in patients with chronic renal failure: a case control study

BackgroundOxidative stress is related to several diseases, including chronic renal insufficiency. The disequilibrium in the oxidant-antioxidant balance is the result of several metabolic changes. The majority of studies to-date have evaluated the grade of oxidative stress with a single biomarker, or a very limited number of them.FindingsThe present study used several important biomarkers to establish a score relating to oxidative stress status (glutathione S-transferase, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, reduced and oxidized glutathione, thiobarbituric acid reactive substances and hemolysis test). The score of oxidative stress (SOS) was then applied to a group of patients with renal insufficiency not on hemodialysis, and compared to healthy control individuals.The score for patients with chronic renal insufficiency was significantly different from that of the healthy control group (0.62 ± 1.41 vs. -0.05 ± 0.94; p < 0.001). The comparison between patients with chronic renal insufficiency and control individuals showed significant differences with respect to changes in the enzymatic antioxidant systems (glutathione S-transferase, glutathione reductase), non-enzymatic antioxidant system (oxidized glutathione) and oxidizability (hemolysis test) indicating significant oxidative stress associated with chronic renal insufficiency.ConclusionsPatients with chronic renal insufficiency not on hemodialysis are susceptible to oxidative stress. The mechanisms that underlie this status are the consequence of changes in glutathione and related enzymes. The SOS scoring system is a useful biochemical parameter to evaluate the influence of oxidative stress on the clinical status of these patients.

Polyphenol-rich foods exhibit DNA antioxidative properties and protect the glutathione system in healthy subjects.

SCOPE Polyphenols (ingested via food items) can decrease DNA, and oxidative damage of proteins and lipids. However, polyphenol effects in healthy populations have not been well defined. The aim of this study was to assess the relationship between urinary total polyphenol excretion (TPE), a biomarker of total polyphenol intake (TPI), polyphenol-rich foods, and oxidative stress biomarkers in healthy adults of different ages participating in the cross-sectional PAScual MEDicina study. METHODS AND RESULTS Urinary TPE was determined by Folin-Ciocalteau method in spot urine samples of 81 participants (46 women), classified into three age groups: 18 to 39, 40 to 54, and 55 to 72 years of age. TPI was quantified from 3-day dietary records using the Phenol-Explorer database. Urinary TPE increased with age (p < 0.001). Urinary TPE was inversely associated with urinary 8-hydroxydeoxyguanosine (8-OHdG; p<0.001) and erythrocyte-oxidized glutathione concentrations (p < 0.05). A negative association between urinary 8-OHdG and daily intake of polyphenols from vegetables and fermented beverages such as red wine was observed. CONCLUSION Urinary TPE increased with age and may reflect attenuation of oxidative damage. These results could explain the beneficial effects in healthy individuals of a diet rich in vegetables and moderate red wine; food items typical of the Mediterranean diet.

Lipidomics to analyze the influence of diets with different EPA:DHA ratios in the progression of Metabolic Syndrome using SHROB rats as a model

The role of specific proportions of ω-3 EPA and DHA, in the modulation of inflammation and oxidative stress markers associated to the progression of Metabolic Syndrome was investigated. Potential inflammatory eicosanoids and docosanoids were discussed together to biomarkers of CVD, obesity, inflammation and oxidative stress in an animal model of metabolic disorders. Results evidenced a noteworthy health effect of 1:1 and 2:1 EPA:DHA proportions over 1:2 EPA:DHA based diets through a down-regulation in the production of strong pro-inflammatory ω-6 eicosanoids, a decrement of biomarkers of oxidative stress, and a modulation of fatty acid desaturase activities and plasma and membrane PUFAs towards greater anti-inflammatory profiles. Outcomes contribute to the general knowledge on the health benefits of marine lipids and their role on the progress of MetS, inflammation and oxidative stress. Results shed light on controversial protective mechanisms of EPA and DHA to better design dietary interventions aimed at reducing MetS.

Diet, iron biomarkers and oxidative stress in a representative sample of Mediterranean population

BackgroundThe consumption pattern characterized by high consumption of vegetables, fruit, fish, olive oil and red wine has been associated with improvements in the total antioxidant capacity of individuals and reduced incidence of diseases related to oxidation. Also, high body iron levels may contribute to increase the oxidative stress by the generation of reactive oxygen species. The objective of this study is to analyze the relationship between antioxidant and pro-oxidant factors obtained from the diet and iron biomarkers on lipoprotein oxidation and total antioxidant capacity in a representative sample of the Mediterranean population.MethodsCross-sectional prospective study, carried out with 815 randomly selected subjects (425 women and 390 men). Dietary assessment (3-day food records), iron biomarkers (serum ferritin, serum iron and transferrin saturation), biochemical markers of lipoperoxidation (TBARS), antioxidant capacity (ORAC) and CRP (C-Reactive Protein) were determined. Multiple Linear Regression (MLR) models were applied to analyze the association between diet factors and iron biomarkers on TBARS and ORAC levels.ResultsWe observed that lipoperoxidation measured by TBARS increased by age but no differences were observed by sex. Antioxidant capacity measured by ORAC is independent of age and sex. In general, increasing age, tobacco, heme iron intake from meat and fish and transferrin saturation were independently and positively associated with TBARS, while non-heme iron was negatively associated. Vegetables, vitamin C intake and serum ferritin were positively associated with ORAC, whereas saturated fatty acids and meat intake were negatively associated.ConclusionsIn our general population, we observed that oxidative stress is related to aging, but antioxidant capacity is not. The highest intake of dietary non-heme iron, vegetables and vitamin C intake exerts a protective effect against oxidation while the highest intake of dietary heme iron from meat and fish and saturated fatty acids are associated with increased oxidative stress. High levels of circulating iron measured by transferrin saturation are associated with increased oxidative stress in women however its association with the higher levels of serum ferritin is controversial.

Follow-up of a healthy lifestyle education program (the Educació en Alimentació Study): 2 years after cessation of intervention

PURPOSE The Educació en Alimentació (EdAl) program conducted over 28 months in primary school children reduced obesity (OB) prevalence in boys and increased voluntary physical activity (PA). The continued benefit after cessation of EdAl is unknown. We assessed the changes in OB prevalence and healthy lifestyle in 11- to 13-year-old adolescents, the age group that had complete inclusion data available 2 years after the EdAl programs conclusion. METHODS Adolescents (n = 421 intervention; n = 198 control) with data at baseline and 2-year follow-up were recruited. Analyses included body mass index (BMI), BMI z-score, and lifestyle data (from questionnaires). RESULTS Between baseline and 2-year follow-up, OB prevalence was reduced (-5.5%; p < .01) and BMI z-score (-.29; p < .001) in intervention compared with control group. BMI z-score was effectively reduced in intervention in both genders: -.26 units in boys and -.32 units in girls, compared with control group. The ≥4 hours/week after-school PA was increased significantly by 13.1% in adolescents of intervention group compared with control group (p = .023); a tendency toward increased PA in intervention girls was observed (p = .062). At 2-year follow-up, participating in ≥4 hours/week after-school PA (odds ratio, .240; p = .002) and daily fruit consumption (odds ratio, .447; p = .025) were protective factors against OB, whereas ≤2 hours/week after-school PA was a risk factor for OB. CONCLUSIONS At 2-year follow-up, the EdAl program induced a lowering of BMI z-score and OB prevalence, compared with control group. After-school PA practice can be stimulated in primary school as part of a healthy lifestyle and maintained subsequently despite cessation of the intervention program.

Targets of protein carbonylation in spontaneously hypertensive obese Koletsky rats and healthy Wistar counterparts: a potential role on metabolic disorders.

UNLABELLED The study innovatively pinpoints target proteins of carbonylation, a key PTM induced by oxidative stress, in the SHROB (genetically obese spontaneously hypertensive) rat model of metabolic syndrome (MetS). Protein carbonylation was assessed by a fluorescence-labeling proteomics approach, and complemented with biometric and biochemical markers of MetS. SHROB and healthy Wistar rats were fed two diets, soybean and linseed oil supplementations, in order to distinguish intrinsic carbonylation of SHROB animals from diet-modulated carbonylation unrelated to MetS. First exploratory data showed similar carbonylation patterns and metabolic conditions in SHROB rats fed soybean and linseed, but different from Wistar animals. A total of 18 carbonylated spots in liver, and 12 in skeletal tissue, related to pathways of lipid (29.6%), carbohydrate (25.9%) and amino acid (18.5%) metabolisms, were identified. In particular, SHROB animals present higher carbonylation in four liver proteins belonging to lipid metabolism, redox regulation and chaperone activity (ALDH2, PDI, PDIA3, PECR), and in the skeletal muscle ALDOA that is involved in muscle dysfunction. Conversely, SHROB rats display lower carbonylation in liver albumin, AKR1C9, ADH1 and catalase. This investigation provides a novel perspective of carbonylation in the context of metabolic disorders, and may be a starting point to characterize new redox pathways exacerbating MetS. BIOLOGICAL SIGNIFICANCE Oxidative stress is a concomitant factor in the pathogenesis of MetS that induces oxidative PTM as carbonylation. Through the use of a redox proteomics approach, we have thoroughly mapped the occurrence of protein targets of carbonylation in the genetically-induced MetS model SHROB rat. The present research brings a new insight of MetS pathogenesis and it may provide valuable information to understand the biological impact of oxidative stress in patients with MetS.