Aumento de estresse oxidativo no sangue de pacientes com ostomia / Increased oxidative stress in the blood of ostomy patients

ABSTRACT BACKGROUND: Ostomy is a surgical procedure that creates a stoma that aims to construct a new path for the output of feces or urine. The relationship of oxidative stress (OxS) markers in patients with ostomy is still poorly described. OBJECTIVE: The present study was aimed at investigating the changes in oxidative stress parameters in peripheral blood collected from ostomy patients when compared with a healthy control group. METHODS: It was evaluated 29 ostomy patients and 30 healthy control patients. The oxidative stress parameters evaluated were: lipid peroxidation [lipid hydroperoxide (LPO), 8-isoprostane (8-ISO) and 4-hydroxynonenal (4-HNE)], protein oxidation and nitration [carbonyl and 3-nitrotyrosine (3-NT)] and DNA oxidation [8-hydroxy-2'-deoxyguanosine (8-OHDG)] in serum from ostomy patients compared to health controls. RESULTS: The data showed an increase of LPO, 8-ISO, 4-HNE, 3-NT and 8-OHDG in serum collected from ostomy patients when compared to healthy controls. CONCLUSION: The findings support the hypothesis that ostomy triggers the oxidative stress observed in the blood collected from these patients.

RESUMO CONTEXTO: Ostomia é um procedimento cirúrgico que cria um estoma com objetivo de construir um novo caminho para a saída das fezes ou urina. A relação dos marcadores de estresse oxidativo em pacientes ostomizados ainda é pouco descrita. OBJETIVO: O presente estudo tem como objetivo investigar as alterações dos parâmetros de estresse oxidativo em sangue de pacientes ostomizados comparados a controles saudáveis. MÉTODOS: Foram avaliados 29 pacientes ostomizados e 30 controles saudáveis. Os parâmetros de estresse oxidativo avaliados foram: peroxidação lipídica [hidroperóxido de lipídio (LPO), 8-isoprostano (8-ISO) e 4-hidroxinonenal (4-HNE)], oxidação e nitração de proteínas [carbonila e 3-nitrotirosina (3-NT)] e oxidação do DNA [8-hidroxi-2'-desoxiguanosina (8-OHDG)] em soro de pacientes ostomizados comparados a controles saudáveis. RESULTADOS: Os dados mostraram um aumento de LPO, 8-ISO, 4-HNE, 3-NT e 8-OHDG em soro de pacientes ostomizados em comparação a controles saudáveis. CONCLUSÃO: Os achados sustentam a hipótese de que a ostomia desencadeia o estresse oxidativo observado no sangue coletado destes pacientes.

Radioiodine-induced oxidative stress in patients with differentiated thyroid carcinoma and effect of supplementation with vitamins C and E and selenium (antioxidants)

ABSTRACT Objective The objective of this study, in addition to confirming that therapy with 131I causes oxidative stress, was to evaluate the effect of supplementation with vitamins C and E and selenium on this phenomenon by measuring plasma 8-epi-PGF2a, a marker of lipid peroxidation. Subjects and methods Forty patients with thyroid cancer submitted to thyroidectomy, who received 3.7 GBq 131I after levothyroxine withdrawal, were selected; 20 patients did not receive (control group) and 20 patients received (intervention group) daily supplementation consisting of 2000 mg vitamin C, 1000 mg vitamin E and 400 µg selenium for 21 days before 131I. Plasma 8-epi-PGF2a was measured immediately before and 2 and 7 days after 131I. Results A significant increase in plasma 8-epi-PGF2a after 131I was observed in the two groups. The concentrations of 8-epi-PGF2α were significantly higher in the control group before and 2 and 7 days after 131I. The percentage of patients with elevated 8-epi-PGF2α was also significantly higher in the control group before and after 131I. Furthermore, the increase (percent) in 8-epi-PGF2α was significantly greater in the control group (average of 112.3% versus 56.3%). Only two patients (10%) reported side effects during supplementation. Conclusions Ablation with 131I causes oxidative stress which can be minimized by the use of antioxidants.

Antioxidant supplementation decreases the cell death rate in the prostatic stromal tissue of long-term castrated rats

OBJECTIVE: The purpose of this study was to compare the effects of castration on cell death rate of the adult rat prostates and to evaluate the benefic action of alpha tocopherol supplementation to avoid apoptosis post-orchiectomy. MATERIAL AND METHODS: Thirty male Wistar rats weighing 250-300g were divided into three groups: group I - they were subjected to bilateral orchiectomy and sacrificed eight weeks after the procedure; group II - subjected to bilateral orchiectomy and alpha-tocopherol supplementation for four weeks preceding the procedure; and group III - subjected to bilateral orchiectomy and alpha-tocopherol supplementation for four weeks preceding the procedure and for eight weeks afterwards. At the end of the experiment, the prostatectomy was performed in all rats. The presence of oxidative stress was determined by assaying the blood level of 8-isoprostane and the occurrence of apoptosis was evaluated by identification of active caspase-3 through immunohistochemical analysis. RESULTS: The statistic analysis of active caspase-3 showed that in the long-term castrated group the detection was higher than in groups were the alpha-tocopherol was supplemented (p=0.007). Analysis of 8-isoprostane levels showed higher concentrations of reactive oxygen species in group I compared to other groups (p<0.05). Groups II and III presented active caspase-3 lower than in group I (p<0.05). CONCLUSION: Our exploratory analyses demonstrate a method to study the aging process and its influence on oxidative stress of prostatic tissue and cells death rate. Based on our results we can suggest that alpha tocopherol supplementation can decrease the apoptotic process as well as the oxidative stress levels induced by androgen deprivation of the prostate gland.

[Plasma free 8-iso-PGF2alpha levels in normotensive and preeclamptic pregnancies]

Preeclampsia is a main cause of morbidity and mortality of pregnant women worldwide. Recently oxidative stress was considered as a part of pathophysiolgy of preeclamsia and 8-isc% prostaglandin F2alpha [8-iso-PGF2 alpha] is known as a marker of oxidative stress. The purpose of this study was to measure and compare plasma concentration of free 8-iso-PG F2 alpha in women with normotensive and preeclamptic pregnancies. In this descriptive-analytic study, Plasma free 8-iso-PGF2 alpha levels were measured in pregnant women with preeclamsia [n=42] and normotensive pregnant women [n=39] between 28-38 weeks of gestation. Women in two groups were matched in age, gestational age and socioeconomic statue and all women were nulligravid. Free 8-iso-PGF2 alpha levels were not significantly different in women with preeclamsia and normotensive group [17808 vs. 24288 pg/dl, NS]. Plasma free 8-iso-PGF2 alpha levels were increased in severe compared to mild preeclampsia [NS]. Neonates weight of preeclamptic mothers was significantly lower than neonates of normotensive women [p<0.0001]. Although free 8-iso-PGF2 alpha is a marker of oxidative stress in vitro, but its measurement is not valuable in clinical medicine. However, further studies in normal pregnancy and preeclampsia will be needed

Oxidative stress and inflammatory marker: possible pathogenic role in acute coronary syndrome

Acute coronary syndrome [ACS], which comprise unstable angina [UA] and acute myocardial infarction [AMI] are multifactor diseases involving both thrombotic and inflammatory processes. C-reactive protein [CRP] has emerged as independent risk indicator of active atherosclerosis. Reactive oxygen species [ROS] are key mediators of signaling pathways that underlie vascular inflammation in atherogenesis starting from the initiation of fatty streak development through lesion progression to ultimate plaque rupture. CRP directly up-regulate AND[P]H oxidase p22 [phox] and enhance ROS generation. Recently it has been shown that 8-iso-prostaglandin F2 alpha [8-iso-PGF2_] is a specific, chemically stable and quantitative marker of oxidative stress in vivo. It is formed in situ in cell membranes following free radical attack on the arachidonic acid. To counteract the effect of ROS, cells are endowed with a complex antioxidant network that operates to prevent or limit oxidant damage. The present study was designed to investigate the changes of 8-iso-PGF2_, total antioxidant capacity [TAC] and CRP levels in patients with acute coronary syndrome in order to evaluate the role of oxidative stress as well as inflammation in pathogenesis and consequence of the disease. The present study included 30 patients with ACS and 15 healthy, age and sex-matched controls. The patients were divided into two groups; 15 patients with UA and 15 patients with AMI. Serum leuel of 8-iso-PGF2-_ was measured using an ELISA kit Serum CRP and TAC levels was measured by turbidimetric immunoassay and colorimetric methods respectively. Serum levels of both 8-iso-PGF2- _, and CRP were significantly increased in patients compared with control [p<0.05]. TAG showed significant decrease in patients with AMI when compared to controls [p<0.05]. It could be concluded that elevated levels of 8-iso-PGF2-_ and CRP together with decreased TAC level contribute directly and actively to the pathogenesis of ACS. The oxidative stress is likely to either induce or intensify the inflammatory action, and may co-affect with inflammatory factors to accelerate plaque rupture. The evaluation of oxidative stress would enable formulation of specific antioxidant therapy as promising strategy against atherogenesis for an early intervention and better management of the disease

Prostaglandin I2 and F2 in schistosomal cor pulmonale

This study was carried to study the prostaglandins in 15 schistosomal cor pulmonale patients [group I] and to compare them with schistosomal patients without cor pulmonale [group II, 10 patients] and normal controls [group III, 10 persons]. The levels of I2 degradation [6- keto PGF 1-alpha vasodilator] and PGF 2-alpha [vasoconstrictor] were measured in the groups. The plasma level of 6-keto PGF 1- alpha was significantly lower in group I as compared with other two groups as regards arterial and venous samples. The plasma level of PGF 2-alpha was significantly higher in both groups I and II, as regards the venous blood samples, in comparison with group III. However, the arterial blood samples showed insignificant difference between the three groups. The ratio of vasodilator prostaglandin [6- keto PGF 1- alpha] to the vasoconstrictor one [PGF 2-alpha] was significantly lower in group I as compared with group II and III and this probably plays an important role in the development of pulmonary hypertension

Prostaglandin F2 alpha in leprosy--a preliminary study.

Prostaglandin F2 alpha was estimated in the sera of fifty patients in the leprosy spectrum to find out the status of prostaglandins in response to Mycobacterium leprae. Contrary to expectation, PGF2 alpha could be detected in only twenty-eight percent of leprosy patients. This preliminary finding is discussed in detail in the paper.