Alexandre Quintanilha

Free radicals and tissue damage produced by exercise

Summary We report a two- to three-fold increase in free radical (R • ) concentrations of muscle and liver following exercise to exhaustion. Exhaustive exercise also resulted in decreased mitochondrial respiratory control, loss of sarcoplasmic reticulum (SR) and endoplasmic reticulum (ER) integrity, and increased levels of lipid peroxidation products. Free radical concentrations, lipid peroxidation, and SR, ER, and mitochondrial damage were similar in exercise exhausted control animals and non-exercised vitamin E deficient animals, suggesting the possibility of a common R • dependent damage process. In agreement with previous work showing that exercise endurance capacity is largely determined by the functional mitochondrial content of muscle (1–4), vitamin E deficient animals endurance was 40% lower than that of controls. The results suggest that R • induced damage may provide a stimulus to the mitochondrial biogenesis which results from endurance training.

Changes in the glutathione status of plasma, liver and muscle following exhaustive exercise in rats

Glutathione Oxidative stress Physical exercise

The inflammatory response in mild and in severe psoriasis

Background  Psoriasis is a chronic and recurrent inflammatory skin disease. The inflammatory response represents a fundamental ability of the organism to protect itself from infectious agents and from injury.

Dislipidemia and oxidative stress in mild and in severe psoriasis as a risk for cardiovascular disease

Psoriasis is a common chronic and recurrent inflammatory skin disorder that has been associated with oxidative stress, abnormal plasma lipid metabolism and with high frequency of cardiovascular events. This prevalence seems to be related to the severity of psoriasis, as it occurs more frequently in patients presenting large areas of the body affected with psoriasis lesions. The aim of our work was to evaluate the development of oxidative stress and of dislipidemia in psoriasis, and to look for a correlation between their levels and worsening of psoriasis. We evaluated lipid profile, total antioxidant capacity, antioxidant vitamins A and E, and lipoperoxidation products. The study was performed in controls and in patients presenting mild and severe psoriasis. Patients presented risk changes in lipid profile (a rise in cholesterol (P<0.01), triglycerides (P<0.001), low density lipoprotein cholesterol (P<0.01), very low density lipoprotein cholesterol (P<0.01), apolipoprotein B (P<0.001) and lipoprotein(a) (P<0.001); and a reduction in high density lipoprotein cholesterol (P<0.001)), a rise in lipoperoxidation products (P<0.001) and a reduction in total antioxidant capacity (P<0.001) and in antioxidant vitamins A (P<0.001) and E (P<0.05). Moreover, we found that the worsening of psoriasis was associated with the enhancement of oxidative stress and of the lipid risk changes. Our data suggest that psoriasis patients must be considered as a group at risk for cardiovascular disease and that this risk seems to be higher in severe psoriasis. In addition, a possible benefit of an enriched diet or of a supplement of vitamins A and E in psoriasis patients should be further studied.

MEMBRANE EFFECTS OF VITAMIN E DEFICIENCY: BIOENERGETIC AND SURFACE CHARGE DENSITY STUDIES OF SKELETAL MUSCLE AND LIVER MITOCHONDRIA*

Vitamin E deficiency in rats increased the sensitivity of liver and muscle mitochondria to damage during incubation at various temperatures, irradiation with visible light, or steady-state respiration with substrates. In all cases, vitamin E-deficient mitochondria exhibited increased lipid peroxidation, reduced transmembrane potential, decreased respiratory coupling, and lower rates of electron transport compared to control mitochondria. Muscle mitochondria always showed greater negative inner membrane surface charge density, and were also more sensitive to damage than were liver mitochondria. Vitamin E-deficient mitochondria also showed slightly more negative inner membrane surface charge density compared to controls. The relationship observed between greater negative surface potential and increased sensitivity to damage provides for a new and sensitive method to probe further the role of surface charge in membrane structure and function. Implications of these new findings for the well-known human muscle myopathies and those experimentally induced by vitamin E deficiency in animals are discussed.

HYDROGEN PEROXIDE-INDUCED CARBONYLATION OF KEY METABOLIC ENZYMES IN SACCHAROMYCES CEREVISIAE : THE INVOLVEMENT OF THE OXIDATIVE STRESS RESPONSE REGULATORS Yap1 AND Skn7

H(2)O(2) induces a specific protein oxidation in yeast cells, and the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (Tdh) is a major target. Using a 2D-gel system to study protein carbonylation, it is shown in this work that both Tdh2p and Tdh3p isozymes were oxidized during exposure to H(2)O(2). In addition, we identified two other proteins carbonylated and inactivated: Cu,Zn-superoxide dismutase and phosphoglycerate mutase. The oxidative inactivation of Cu,Zn-superoxide dismutase decreases the antioxidant capacity of yeast cells and probably contributes to H(2)O(2)-induced cell death. Cyclophilin 1 was also carbonylated, but CPH1 gene disruption did not affect peroxide stress sensitivity. The correlation between H(2)O(2) sensitivity and the accumulation of oxidized proteins was evaluated by assaying protein carbonyls in mutants deficient in the stress response regulators Yap1p and Skn7p. The results show that the high sensitivity of yap1delta and skn7delta mutants to H(2)O(2) was correlated with an increased induction of protein carbonylation. In wild-type cells, the acquisition of stress resistance by pre-exposure to a sublethal H(2)O(2) stress was associated with a lower accumulation of oxidized proteins. However, pre-exposure of yap1delta and skn7delta cells to 0.4 mM H(2)O(2) decreased protein carbonylation induced by 1.5 mM H(2)O(2), indicating that the adaptive mechanism involved in the protection of proteins from carbonylation is Yap1p- and Skn7p-independent.

Mitochondrial superoxide dismutase is essential for ethanol tolerance of Saccharomyces cerevisiae in the post-diauxic phase

This work reports the role of both superoxide dismutases-CuZnSOD (encoded by SOD1) and MnSOD (encoded by SOD2)-in the build-up of tolerance to ethanol during growth of Saccharomyces cerevisiae from exponential to post-diauxic phase. Both enzyme activities increase from the exponential phase to the diauxic shift and from the diauxic shift to the post-diauxic phase. The levels of mRNA-SOD1 and mRNA-SOD2 increase from the exponential phase to the diauxic shift; however, during the post-diauxic phase mRNA-SOD1 levels decrease while mRNA-SOD2 levels remain unchanged. These data indicate the existence of two regulatory mechanisms involved in the induction of SOD activity during growth: synthesis de novo of the proteins (until the diauxic shift), and post-transcriptional or post-translational regulation (during the post-diauxic phase). Ethanol does not alter the activities of either enzyme in cells from the diauxic shift or post-diauxic-phases, although the respective mRNA levels decrease in post-diauxic-phase cells treated with ethanol (14% or 20%). Results of experiments with sod1 and sod2 mutants show that MnSOD, but not CuZnSOD, is essential for ethanol tolerance of diauxic-shift and post-diauxic-phase cells. Evidence that ethanol toxicity is correlated with the production of reactive oxygen species in the mitochondria is obtained from results with respiration-deficient mutants. In these cells, the induction of superoxide dismutase activity by ethanol is low; also, the respiratory deficiency restores the capacity of sod2 cells to acquire ethanol tolerance.

Leukocyte activation, erythrocyte damage, lipid profile and oxidative stress imposed by high competition physical exercise in adolescents.

BACKGROUND The aim of this study was to evaluate and to compare the lipid profile and the levels of leukocyte activation, red blood cell (RBC) damage and of oxidative stress in two groups of adolescents, with similar body mass index: high competition swimmers and adolescents practising moderate regular physical exercise. METHODS As markers of leukocyte activation, we measured plasma lactoferrin, elastase and granulocyte-monocyte colony stimulating factor. We studied RBC membrane band 3 profile and membrane-bound hemoglobin, as markers of RBC damage and aging; total and differential leukocyte count and RBC count, hematocrit, hemoglobin concentration and hematimetric indexes were also measured. Lipid profile included the evaluation of triglycerides (TG), total cholesterol (Chol), high-density lipoprotein cholesterol (HDLc), low-density lipoprotein cholesterol (LDLc), apolipoproteins AI and B (Apo AI and B), and lipoprotein (a) (Lp(a)). To evaluate oxidative stress, lipoperoxidation products and total antioxidant capacity were measured. RESULTS We found that high competition adolescents presented increased plasma levels of leukocyte activation products, increased RBC damage suggesting aging and premature removal, and higher oxidative stress. Lipid profile showed some risk and some protective changes. CONCLUSIONS Our data suggest that high competition exercise, by imposing a higher and sustained oxidative and proteolytic stress, may contribute in the future to a higher risk of cardiovascular disease. We believe these findings warrant a reevaluation of current views in the intensity, duration and regularity of physical exercise, and that the evaluation of leukocyte activation products, RBC damage, oxidative stress and lipid profile may represent good markers to establish putative protective thresholds.

Interleukin (IL)-22, IL-17, IL-23, IL-8, vascular endothelial growth factor and tumour necrosis factor-α levels in patients with psoriasis before, during and after psoralen-ultraviolet A and narrowband ultraviolet B therapy.

Background  Several cross‐sectional studies have shown that different cytokines and growth factors are enhanced in psoriasis.

C-reactive protein and leucocyte activation in psoriasis vulgaris according to severity and therapy

Background  Psoriasis vulgaris is a chronic recurrent inflammatory skin disease and psoriatic lesions have shown leucocyte infiltration.