[Study of oxidative stress in advanced kidney disease]. / Estudio del estrés oxidativo en enfermedad renal avanzada.

INTRODUCTION: Introduction Patients with Chronic renal Disease (CRD) often have cardiovascular disease that is the main cause of morbidity and mortality. Oxidative stress and a subclinical inflammation are crucial factors in its development. The aim of this study was to asses the oxidation of the main molecular lines in patients with advanced renal disease without dialysis and to determinate the best biomarker to asses this stress. PATIENTS AND METHODS: We performed an observational study to measure the most important oxidative biomarkers in 32 patients with stage 4 CRD (MDRD = 22.1 +/- 1.08 ml/min) compared with the values obtained in a control group. In peripheral lymphocytes we measured, the lipid peroxidation by Malondialdehyde (MDA) and F2 Isoprostanes in plasma; protein oxidation by glutathione oxidized/reduced ratio (GSSG/GSH) in peripheral lymphocytes and protein carbonyls in plasma and the oxidative damage in genetic material by modified nucleotide base 8-deoxiguanosina oxo -(8-oxo-dG), after isolating nuclear and mitochondrial DNA. We also studied the antioxidant defenses with superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GSR) and catalase (CAT) in peripheral lymphocytes. We studied the correlation between oxidative stress and the renal function and oxidative stress and co-morbidity factors. RESULTS: All biomarkers showed important differences in comparison with the control subjects. 821.89 +/- 300.47 ng/ml vs. 270 (95.66) * ng/ml (p < 0.000), MDA 0.11 (0.11) * vs. 0.7 +/- 0.31 nmol/mg prot (p <0.000). GSSG / GSH: 6.89 +/- 1.91 vs. 1.39 +/- 0.75 (p <0.000), protein carbonyls: 7.41 +/- 0.84 vs. 3.63 (1.12) *. Nuclear 8-oxo-dG 7.88 (2.32) vs. 2.96 (1.78) * mitochondrial 8-oxo-dG: 15.73 +/- 2.28 vs. 13.85 +/- 1.44 (p <0.05). The Antioxidant enzymes also showed differences. Nuclear 8-oxo-dG demonstrated an important relationship with the rest of biomarkers, homocysteine (r = 0.305, p <0.05), lipoprotein (a) (r = 0.375, p <0.01), mitochondrial 8-oxo-dG (r = 0.411, p <0.05), GSSH/GSH (r = 0.595, p <0.001) and protein carbonyls (r = 0.489, p <0.05). There was an inverse correlation with total protein (r = -0.247, p <0.01), GSH (r = -0.648, p <0.000), GSR (r = -0.563, p <0.001) and SOD (r = -0.497, p <0.000). We did not find any correlation between these parameters and renal function. The presence of diabetes or the treatment with statins did not showed significant differences. * Median (Interquartile range). CONCLUSION: There is an important oxidative stress in patients with advanced renal disease, probably established during early stages of disease. Of the studied parameters, the nuclear 8-oxo-dG is the best marker for oxidative stress in CRD.

Estudio del estrés oxidativo en enfermedad renalavanzada / No disponible

Introducción: El estrés oxidativo es crucial para el desarrollo de arteriosclerosis, principal causa de morbimortalidad en población en prediálisis. Nuestro objetivo fue valorar la oxidación de las principales líneas moleculares y discernir si algún biomarcador tenía mejor comportamiento valorando este estrés. Pacientes y método: Estudio observacional en 32 pacientes con MDRD 22,1 ± 1,08 ml/min. Medimos en linfocitos periféricos: malondialdehído, glutatión oxidado/reducido, 8-oxo-deoxiguanosina nuclear y mitocondrial, superóxido dismutasa, glutatión reductasa, glutatión peroxidasa y catalasa, y en plasma F2 isoprostanos y proteínas carboniladas. Correlacionamos los resultados con función renal y factores comórbidos. Resultados: Todos los biomarcadores tuvieron amplias diferencias significativas cuando se compararon con el grupo control peroxidación lipídica: F2 isoprostanos: 821,89 ± 300,47 ng/ml vs. 270 (95,66)* ng/ml (p <0,000); MDA 0,11 (0,11)* vs. 0,7 ± 0,31 nmol/mg prot (p <0,000). Oxidación proteica: GSSG/GSH: 6,89 ± 1,91 vs. 1,39 ± 0,75 (p <0,000); proteínas carboniladas: 7,41 ± 0,84 vs. 3,63 (1,12)*. Daño material genético: 8-oxo-deoxiguanosina nuclear: 7,88 (2,32)* vs. 2,96 (1,78)* y 8-oxo-dG mitocondrial: 15,73 ± 2,28 vs. 13,85 ± 1.44 (p <0,05). Los valores de las enzimas antioxidantes también obtuvieron amplias diferencias significativas. La molécula 8-oxodeoxiguanosina en DNA nuclear fue la que tuvo una relación significativa con el resto de biomarcadores, con homocisteína (r = 0,305; p <0,05), lipoproteína (a) (r = 0,375; p <0,01), 8-oxo-deoxiguanosina mitocondrial (r = 0,411; p <0,05), GSSG/GSH (r = 0,595; p <0,001) y proteínas carboniladas (r = 0,489; p <0,05), y de forma inversa con las proteínas totales (r = -0,247; p <0,01), GSH (r = -0,648; p <0,000), GRS (r = -0,563; p <0,001) y SOD (-0,497; p <0,000). Ninguno de los parámetros tuvo correlación con la función renal. Tampoco se obtuvieron diferencias significativas con la presencia o no de diabetes o la toma de estatinas. * Mediana (amplitud intercuartil). Conclusión: Existe un elevado estrés oxidativo en los pacientes con enfermedad renal avanzada que probablemente se establezca desde fases tempranas de la enfermedad. Entre todos los parámetros estudiados, la molécula de 8-oxo-dG se comportó como el marcador más idóneo (AU)

Introduction: Patients with Chronic Kidney Disease (CKD) often have cardiovascular disease that is the main cause of morbidity and mortality. Oxidative stress and a subclinical inflammation are crucial factors in its development. The aim of this study was to assess the oxidation of the main molecular groups in patients with advanced renal disease without dialysis and to determinate the best biomarker to assess this stress. Patients and Methods: We performed an observational study to measure the most important oxidative biomarkers in 32 patients with stage 4 CKD (MDRD = 22.1 ± 1.08ml/min) compared with the values obtained in a control group. In the peripheral lymphocytes we measured, the lipid peroxidation by Malondialdehide (MDA) and F2 Isoprostanes in plasma; protein oxidation by glutathione oxidized/reduced ratio (GSSG/GSH) in peripheral lymphocytes and protein carbonyls in plasma and the oxidative damage in genetic material by modified nucleotide base 8-deoxiguanosina oxo ¿(8-oxodG), after isolating nuclear and mitochondrial DNA. We also studied the antioxidant defences with superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GSR) and catalase (CAT) in peripheral lymphocytes. We studied the correlation between oxidative stress and the renal function and oxidative stress and co-morbidity factors. Results: All biomarkers showed important differences in comparison with the control subjects. F2 Isoprostanes: 821.89 ± 300.47ng/ml vs. 270 (95.66) * ng/ml (p < 0.000), MDA 0.11 (0.11) * vs. 0.7 ± 0.31nmol/mg prot (p < 0.000). GSSG/GSH: 6.89 ± 1.91 vs. 1.39 ± 0.75 (p < 0.000), protein carbonyls: 7.41 ± 0.84 vs. 3.63 (1.12) *. Nuclear 8-oxo-dG 7.88 (2.32) vs. 2.96 (1.78) * mitochondrial 8-oxo-dG: 15.73 ± 2.28 vs. 13.85 ± 1.44 (p < 0.05). The Antioxidant enzymes also showed differences. Nuclear 8-oxo-dG demonstrated an important relationship with the rest of the biomarkers, homocystein (r = 0.305, p < 0.05), lipoprotein (a) (r = 0.375, p < 0.01), mitochondrial 8-oxodG (r = 0.411, p < 0.05), GSSH/GSH (r= 0.595, p < 0.001) and protein carbonyls (r = 0.489, p < 0.05). There was an inverse correlation with total protein (r = -0.247, p < 0.01), GSH (r = -0.648, p < 0.000), GSR (r = -0.563, p < 0.001) and SOD (r = -0.497, p < 0.000). We did not find any correlation between these parameters and renal function. The presence of diabetes or the treatment with statins did not show significant differences. * Median (Interquartile range). Conclusion: There is an important oxidative stress in patients with advanced renal disease, probably established during the early stages of disease. Of the studied parameters, the nuclear 8-oxo-dG is the best marker for oxidative stress in CRD (AU)

Programa de ejercicio para pacientes con insuficiencia renal crónica en hemodiálisis. Estudio piloto / No disponible

No disponible

Aplidin induces JNK-dependent apoptosis in human breast cancer cells via alteration of glutathione homeostasis, Rac1 GTPase activation, and MKP-1 phosphatase downregulation.

Aplidin is an antitumor agent in phase II clinical trials that induces apoptosis through the sustained activation of Jun N-terminal kinase (JNK). We report that Aplidin alters glutathione homeostasis increasing the ratio of oxidized to reduced forms (GSSG/GSH). Aplidin generates reactive oxygen species and disrupts the mitochondrial membrane potential. Exogenous GSH inhibits these effects and also JNK activation and cell death. We found two mechanisms by which Aplidin activates JNK: rapid activation of Rac1 small GTPase and downregulation of MKP-1 phosphatase. Rac1 activation was diminished by GSH and enhanced by L-buthionine (SR)-sulfoximine, which inhibits GSH synthesis. Downregulation of Rac1 by transfection of small interfering RNA (siRNA) duplexes or the use of a specific Rac1 inhibitor decreased Aplidin-induced JNK activation and cytotoxicity. Our results show that Aplidin induces apoptosis by increasing the GSSG/GSH ratio, a necessary step for induction of oxidative stress and sustained JNK activation through Rac1 activation and MKP-1 downregulation.

Fibrinolysis and lipoprotein(a) in women with coronary artery disease. Influence of hormone replacement therapy.

BACKGROUND AND OBJECTIVES: The incidence of coronary artery disease (CAD) is higher in post-menopausal than in pre-menopausal women. Epidemiological studies suggest that hormone replacement therapy (HRT) decreases the risk of cardiovascular disease in post-menopausal women. HRT could modify the cardiovascular risk via several mechanisms, including modifications in the fibrinolytic system and lipoprotein (a) levels. Our study was aimed at investigating some of these modifications. DESIGN AND METHODS: In the cross-sectional part of the study we evaluated several components of the fibrinolytic system, coagulation inhibitors and lipid profile in premenopausal (n=15) and post-menopausal women (n=64) with CAD and compared these parameters with those of healthy pre-menopausal (n=31) and post-menopausal women (n=88). The prospective part of the study analyzed the effect of HRT with transdermal estrogen with or without progestogen in post-menopausal women with CAD. RESULTS: Pre- and postmenopausal women with CAD showed significant lower fibrinolytic activity and higher plasminogen activator inhibitor type 1 (PAI-1) levels than their control groups. Lp(a) levels were higher in premenopausal women with CAD than in healthy premenopausal women. In post-menopausal women with CAD, HRT induced a significant decrease in PAI-1 and Lp(a) levels. No significant differences were observed in any parameter studied between the groups treated with transdermal estrogen with and without progestogen. INTERPRETATION AND CONCLUSIONS: CAD is associated with a decrease in fibrinolytic activity, possibly due to an increase in PAI-1 levels. An increase in fibrinolytic activity and a decrease in PAI-1 and Lp(a) levels were observed in CAD women receiving transdermal HRT and these changes may have a favorable impact on the risk of new cardiovascular events in post-menopausal CAD women.

Plasminogen activator inhibitor-1 (PAI-1) promoter 4G/5G genotype and increased PAI-1 circulating levels in postmenopausal women with coronary artery disease.

Increased circulating levels of type 1 plasminogen activator inhibitor (PAI-1) have been associated with coronary artery disease (CAD). However, genetic and environmental determinants of PAI-1 expression are only partially understood. The levels of PAI-1 have been found to relate to 4/5 guanosine (4G/5G) polymorphism in the promoter region of the PAI-1 gene. The 4G allele in this polymorphism has been associated with higher levels of plasma PAI-1 activity, but despite the strong correlation between PAI-1 activity and antigen, no association has been found between PAI-1 antigen levels and the PAI-1 promoter 4G/5G genotype. The aim of the present study was to analyze the influence of the PAI-1 promoter 4G/5G genotype on PAI-1 levels in post-menopause women with coronary disease in comparison with healthy women in pre and postmenopausal status, and the influence of this genotype on variations in PAI-1 levels after hormone replacement therapy (HRT). No differences between 4G/5G allele distribution in the groups studied were observed. The group of postmenopausal women with CAD showed significantly increased PAI-1 antigen and activity levels in comparison with the control groups, and the levels of PAI-1 correlated with the 4G/5G genotype. A multivariate analysis revealed that in the CAD group there was a high correlation between 4G allele dosage and PAI-1 antigen levels, which were also influenced by the triglyceride levels but not by estrogen or glucose levels. After hormone replacement therapy the decrease in PAI-1 levels was correlated with the 4G allele dosage. We conclude that in the group of postmenopausal women with CAD the influence of the PAI-1 promoter 4G/5G genotype on PAI-1 levels is more evident than in the control groups, and that the decrease in PAI-1 levels after HRT in CAD women correlates with the 4G allele dosage.

Influence of a rehabilitation sports programme on the fibrinolytic activity of patients after myocardial infarction.

The influence of regular physical exercise on fibrinolysis was studied in two groups of patients after myocardial infarction. The two groups were of similar age and living habits. One of the groups took part in a rehabilitative training programme while the other group did not participate in any sports activities. Several fibrinolytic variables, including plasminogen activator inhibitor (PAI) activity and PAI-1 antigen, were studied before and after an ergometric test performed at three different times: at the end of hospitalization (before beginning the rehabilitation programme), three months and six months after myocardial infarction. Our results indicate that by the sixth month fibrinolytic activity, measured by the tissue plasminogen activator (t-PA) capacity, had decreased significantly (p less than 0.025) in the patients who were not participating in the rehabilitation programme whereas it had increased slightly in the patients involved in the rehabilitation programme in comparison with the initial values. It was also observed that while PAI activity remained constant or decreased slightly in patients after six months in the rehabilitative sports programme, these PAI levels increased significantly in patients who were not in the sports programme. Our results indicate that there was a significant decrease in the fibrinolytic capacity of patients who were not participating in the rehabilitation sports programme, while the patients involved in the rehabilitation programme showed a slight improvement in their fibrinolytic activity.

Plasminogen activator inhibitor activity and other fibrinolytic variables in patients with coronary artery disease.

Several fibrinolytic variables, including plasminogen activator inhibitor activity, were studied before and after exercise in 67 normolipidaemic patients with coronary artery disease and in 25 hyperlipidaemic patients with coronary artery disease. Before exercise plasminogen activator inhibitor activity was higher in the patient groups than in a group of 10 healthy volunteers. For those who were normolipidaemic plasminogen activator inhibitor activity was greater in patients with angina pectoris who had had a myocardial infarction. The concentration of antigenic tissue-type plasminogen activator was similar in all the patients with coronary artery disease and higher than in the control group. After the exercise test fibrinolytic capacity was lower in the patients with angina pectoris and a previous history of myocardial infarction. After exercise both the released immunological tissue-type plasminogen activator and fibrinolytic capacity were lower in the hyperlipidaemic patients than in the normolipidaemic patients. The concentration of plasminogen activator inhibitor was also higher in the hyperlipidaemic patients. Patients with hyperlipidaemia IV had the highest plasminogen activator inhibitor activity. The increase in plasminogen activator inhibitor activity found in the patients was partially inhibited by antiserum against plasminogen activator inhibitor-1 in vitro. The formation of a complex of about 115,000 daltons between plasminogen activator inhibitor and purified tissue-type plasminogen activator was detected by a zymographic fibrin technique. These findings show that in patients with coronary artery disease fibrinolytic activity is impaired by an increase in plasminogen activator inhibitor. Impaired fibrinolysis may be related to the clinical evolution of coronary artery disease in these patients.

Reduced fibrinolytic activity in coronary heart disease in basal conditions and after exercise.

Fibrinolysis may be impaired in coronary heart disease patients. 20 coronary heart disease patients and 10 control subjects were examined for tissue-plasminogen activator activity, tissue-plasminogen activator antigen, fast tissue-plasminogen activator inhibitor and other fibrinolytic and haemostatic parameters including antigenic and functional protein C. Both patient and control groups were similar in age and smoking habits. All of these patients had a myocardial infarction between 1-3 months before this study. Assays were evaluated before and after an exercise test. Prothrombin time, activated partial thromboplastin time, protein C, plasminogen, alpha 2-antiplasmin, fibrinogen/fibrin degradation products and contact-activated fibrinolysis were similar before and after exercise in both groups. Fibrinolytic activity assayed by the euglobulin lysis time and fibrin-plate lysis methods was decreased in the patient group as compared with the control group but the difference was not significant. In basal conditions, tissue-plasminogen activator activity was defective in 50% of the coronary heart disease patients (p less than 0.01) and after exercise this percentage rose to 77% (p less than 0.01). However, tissue-plasminogen activator antigen in the coronary heart disease group was similar to that of the control group, both before and after exercise. The activity of the tissue-plasminogen activator inhibitor was persistently increased in coronary heart disease though this increase was not statistically significant. It is concluded that in coronary heart disease patients there is a defective fibrinolytic activity probably due to an increase in tissue-plasminogen activator inhibitor.