Endothelial NOX5 overexpression induces changes in the cardiac gene profile: potential impact in myocardial infarction?

Cardiovascular diseases and the ischemic heart disease specifically constitute the main cause of death worldwide. The ischemic heart disease may lead to myocardial infarction, which in turn triggers numerous mechanisms and pathways involved in cardiac repair and remodeling. Our goal in the present study was to characterize the effect of the NADPH oxidase 5 (NOX5) endothelial expression in healthy and infarcted knock-in mice on diverse signaling pathways. The mechanisms studied in the heart of mice were the redox pathway, metalloproteinases and collagen pathway, signaling factors such as NFκB, AKT or Bcl-2, and adhesion molecules among others. Recent studies support that NOX5 expression in animal models can modify the environment and predisposes organ response to harmful stimuli prior to pathological processes. We found many alterations in the mRNA expression of components involved in cardiac fibrosis as collagen type I or TGF-β and in key players of cardiac apoptosis such as AKT, Bcl-2, or p53. In the heart of NOX5-expressing mice after chronic myocardial infarction, gene alterations were predominant in the redox pathway (NOX2, NOX4, p22phox, or SOD1), but we also found alterations in VCAM-1 and β-MHC expression. Our results suggest that NOX5 endothelial expression in mice preconditions the heart, and we propose that NOX5 has a cardioprotective role. The correlation studies performed between echocardiographic parameters and cardiac mRNA expression supported NOX5 protective action. (AU)

Extracellular histones trigger oxidative stress-dependent induction of the NF-kB/CAM pathway via TLR4 in endothelial cells

Extracellular histones have been reported to aggravate different pathophysiological processes by increasing vascular permeability, coagulopathy, and inflammation. In the present study, we elucidate how extracellular histones (10–100 µg/mL) concentration dependently increase cytosolic reactive oxygen species (ROS) production using human umbilical vein endothelial cells (HUVECs). Furthermore, we identify cyclooxygenase (COX) and NADPH oxidase (NOX) activity as sources of ROS production in extracellular histone-treated HUVEC. This COX/NOX-mediated ROS production is also involved in enhanced NF-kB activity and cell adhesion molecules (VCAM1 and ICAM1) expression in histone-treated HUVEC. Finally, by using different toll-like receptor (TLR) antagonists, we demonstrate the role of TLR4 in CAMs overexpression triggered by extracellular histones in endothelial cells. In conclusion, our data suggest that through TLR4 signaling, extracellular histones increase endothelial cell activation, a mechanism involving increased COX- and NOX-mediated ROS. These findings increase our understanding on how extracellular histones enhance systemic inflammatory responses in diseases in which histone release occurs as part of the pathological processes. (AU)

Structure, regulation, and physiological functions of NADPH oxidase 5 (NOX5)

NOX5 is the last member of the NADPH oxidase (NOXs) family to be identified and presents some specific characteristics differing from the rest of the NOXs. It contains four Ca2+ binding domains at the N-terminus and its activity is regulated by the intracellular concentration of Ca2+. NOX5 generates superoxide (O2•−) using NADPH as a substrate, and it modulates functions related to processes in which reactive oxygen species (ROS) are involved. Those functions appear to be detrimental or beneficial depending on the level of ROS produced. For example, the increase in NOX5 activity is related to the development of various oxidative stress-related pathologies such as cancer, cardiovascular, and renal diseases. In this context, pancreatic expression of NOX5 can negatively alter insulin action in high-fat diet-fed transgenic mice. This is consistent with the idea that the expression of NOX5 tends to increase in response to a stimulus or a stressful situation, generally causing a worsening of the pathology. On the other hand, it has also been suggested that it might have a positive role in preparing the body for metabolic stress, for example, by inducing a protective adipose tissue adaptation to the excess of nutrients supplied by a high-fat diet. In this line, its endothelial overexpression can delay lipid accumulation and insulin resistance development in obese transgenic mice by inducing the secretion of IL-6 followed by the expression of thermogenic and lipolytic genes. However, as NOX5 gene is not present in rodents and human NOX5 protein has not been crystallized, its function is still poorly characterized and further extensive research is required. (AU)

Hypertension secondary to nitric oxide depletion produces oxidative imbalance and inflammatory/fibrotic outcomes in the cornea of C57BL/6 mice

Arterial hypertension (AH) leads to oxidative and inflammatory imbalance that contribute to fibrosis development in many target organs. Here, we aimed to highlight the harmful effects of severe AH in the cornea. Our experimental model was established by administration of NG-nitro-L-arginine-methyl-ester (L-NAME) to C57BL/6 mice, which were monitored weekly for arterial blood pressure and intraocular pressure (IOP). Morphological studies of ocular tissues were accompanied by analyses of reactive oxygen species generation, and localization/expression of NAPDH oxidase isoforms (NOX1, NOX2, NOX4) and inflammatory biomarkers (PPARα, PPARγ, IL-1β, IL-6, IL-10, TNF-α, and COX-2). Masson’s trichrome and Sirius Red staining were used to explore the fibrotic status of the cornea. The expression of collagen isoforms (COL1α1, COL1α2, COL3α1, COL4α1, COL4α2) and relevant metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) were also quantified to evaluate the participation of collagen metabolism in AH-related corneal damage. Hypertensive animals showed an increase in IOP values, and a thinner cornea compared with normotensive controls. Moreover, AH increased NADPH oxidase activity and reactive oxygen species generation in the cornea, which was accompanied by transcriptional upregulation of NOX isoforms and inflammatory biomarkers, while reducing PPAR expression. L-NAME-treated animals also developed corneal fibrosis with overexpression of collagen isoforms and reduction of factors responsible for collagen degradation. This is the first study reporting structural changes in the cornea and elevated IOP in L-NAME-treated mice. Overexpression of the NADPH oxidase system and collagen deposition might play a substantial role in the pathogenic mechanisms contributing to ocular disturbances in a context of severe hypertension. (AU)

Angiopoietin-like 4 knockdown attenuates cigarette smoke extract–induced oxidative stress and apoptosis in lung bronchial epithelial cells by inhibiting NADPH oxidase

It has been found that angiopoietin-like 4 (ANGPTL4) expression is increased in the serum of patients with chronic obstructive pulmonary disease (COPD). Herein, cigarette smoke extract (CSE) was used to stimulate oxidative stress in bronchial epithelial cells BEAS-2B, and the role and potential mechanism of ANGPTL4 in smoking-induced lung dysfunction were explored. The roles of different concentrations of CSE (0, 1, 2.5, 5, or 10%) in cell viability and ANGPTL4 levels were evaluated. Following ANGPTL4 being knocked down, the effects of ANGPTL4 knockdown on oxidative stress and apoptosis were determined. Moreover, the level of NADPH oxidase 2 (NOX2) was upregulated to assess the mediated role of NOX in the regulation of ANGPTL4, along with JNK/p38 MAPK signaling. CSE treatment elevated the level of ANGPTL4, and ANGPTL4 knockdown reduced CSE-induced oxidative stress, apoptosis, and NOX level in BEAS-2B cells. The greatest degree of alteration was found in NOX2, and additional NOX2 overexpression broke the inhibitory influences of ANGPTL4 knockdown on oxidative stress and apoptosis. Otherwise, ANGPTL4 knockdown hindered the activation of JNK/p38 MAPK signaling, whereas NOX2 overexpression activated this signaling pathway. Together, ANGPTL4 knockdown attenuated CSE-induced oxidative stress, apoptosis, and activation of JNK/MAPK signaling by inhibiting NOX (AU)

Especies reactivas de oxígeno: papel en la función vascular y en la disfunción endotelial asociada a la enfermedad metabólica / Reactive oxygen species: role in vascular function and in metabolic disease-associated endothelial dysfunction

El estrés oxidativo, alteración de la homeostasis REDOX en células y tejidos con un incremento de los niveles de especies reactivas de oxígeno (ROS), es un mecanismo patogénico común a múltiples patologías como las enfermedades cardiovasculares, los desórdenes neurodegenerativos, la inflamación y el cáncer, razón por la cual ha existido una investigación intensa en las últimas décadas sobre los posibles efectos protectores de las terapias antioxidantes en estas enfermedades. No obstante, la señalización REDOX juega, por otra parte, un papel crítico en la homeostasis y supervivencia celular, y las ROS son producidas en pequeñas cantidades durante la función celular normal. Las investigaciones llevadas a cabo en nuestro grupo han estado enfocadas al estudio del estrés oxidativo como factor patogénico clave en la disfunción endotelial en la obesidad y en otros estados de resistencia a la insulina. La disfunción endotelial subyace a las complicaciones vasculares de la diabetes y la obesidad, y representa un fenotipo endotelial mal adaptado con alteración de la función vasodilatadora, angiogénica y de barrera del endotelio, lo que conduce a un estado vasoconstrictor, proinflamatorio y protrombótico de la pared vascular. Debido a su capacidad de inhabilitar el óxido nítrico (NO), las ROS son en parte responsables de la disfunción endotelial. Por otra parte, nuestros estudios durante estos años han permitido caracterizar el papel clave de ROS como el H2O2 en la función endotelial de arterias de resistencia renales y coronarias, y su participación en la función vascular mediante la modulación de canales iónicos y enzimas implicados en vías de señalización de la pared arterial. Estas investigaciones sugieren la necesidad de valorar el papel de las ROS en los procesos fisiológicos de los distintos lechos vasculares y de revisar los esfuerzos en la búsqueda de terapias antioxidantes para las complicaciones vasculares de estados de resistencia a la insulina teniendo en cuenta la implicación de las ROS en la función endotelial normal. Palabras clave: especies reactivas de oxígeno (ROS), endotelio vascular, hiperpolarización derivada del endotelio (EDH), estrés oxidativo, obesidad, disfunción endotelial

Oxidative stress, impairment of REDOX homeostasis in cells and tissues leading to increased levels of reactive oxygen species (ROS), is a pathogenic mechanism underlying numerous pathologies including cardiovascular diseases, cancer, neurodegenerative disorders and inflammation. Therefore, there has been an intensive investigation during the last decades on the potential protective effects of antioxidant therapies on these disorders. Nevertheless, REDOX signaling plays a critical role in homeostasis and cell survival, and ROS are produced in small amount during normal cell function. Investigations carried out in our group during the last decade have been focused on the study of oxidative stress as a key pathogenic factor in endothelial and vascular dysfunction of resistance arteries in obesity and other insulin resistant states. Endothelial dysfunction underlies vascular complications of diabetes and obesity, and represents a maladapted endothelial phenotype consisting of impaired vasodilatation, angiogenesis and barrier function leading to a vasoconstrictor, pro-inflammatory and pro-thrombotic state of the vascular wall. ROS are involvedin endothelial dysfunction since they reduce bioavailability of nitric oxide (NO). On the other hand, our investigations have provided evidence for a key role of ROS such as hydrogen peroxide (H2O2) in the endothelial function of healthy coronary and renal resistance arteries, and its involvement in vascular function through modulation of ion channels and enzymes involved in signalling pathways of the arterial wall.These investigations suggest the need to assess the functional role of ROS in the different vascular beds and to revise the efforts in the search of antioxidant therapies for vascular complications of metabolic diseases by taking into account ROS involvement in endothelial function

Reactive oxygen species derived from NAD(P)H oxidase play a role on ethanol-induced hypertension and endothelial dysfunction in rat resistance arteries

Chronic ethanol consumption is a risk factor for cardiovascular diseases. We studied whether NAD(P)H oxidase-derived reactive oxygen species (ROS) play a role in ethanol-induced hypertension, vascular dysfunction, and protein expression in resistance arteries. Male Wistar rats were treated with ethanol (20 % v/v) for 6 weeks. Ethanol treatment increased blood pressure and decreased acetylcholine-induced relaxation in the rat mesenteric arterial bed (MAB). These responses were attenuated by apocynin (30 mg/kg/day; p.o. gavage). Ethanol consumption increased superoxide anion (O2−) generation and decreased nitrate/nitrite (NOx) concentration in the rat MAB and apocynin prevented these responses. Conversely, ethanol did not affect the concentration of hydrogen peroxide (H2O2) and reduced glutathione (GSH) or the activity of superoxide dismutase (SOD) and catalase (CAT) in the rat MAB. Ethanol increased interleukin (IL)-10 levels in the rat MAB but did not affect the levels of tumor necrosis factor (TNF)-α, IL-6, or IL-1β. Ethanol increased the expression of Nox2 and the phosphorylation of SAPK/JNK, but reduced eNOS expression in the rat MAB. Apocynin prevented these responses. However, ethanol treatment did not affect the expression of Nox1, Nox4, p38MAPK, ERK1/2, or SAPK/JNK in the rat MAB. Ethanol increased plasma levels of TBARS, TNF-α, IL-6, IL-1β, and IL-10, whereas it decreased NOx levels. The major finding of our study is that NAD(P)H oxidase-derived ROS play a role on ethanol-induced hypertension and endothelial dysfunction in resistance arteries. Moreover, ethanol consumption affects the expression and phosphorylation of proteins that regulate vascular function and NAD(P)H oxidase-derived ROS play a role in such responses (AU)

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Omega-3 fatty acids control productions of superoxide and nitrogen oxide and insulin content in INS-1E cells

Omega-3 fatty acids have multiple effects in peripheral tissues and pancreatic beta cell function. Dietary depletion of omega-3 fatty acids is associated with pancreatic islet dysfunction and insulin resistance in rats. Herein, the effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on pancreatic beta cell redox state and function were investigated. INS-1E insulin-secreting cells were incubated with EPA and DHA in combination with palmitic acid, and productions of reactive oxygen species (ROS), nitric oxide (NO) and insulin were measured. The involvement of the NADPH oxidase complex in ROS production and expression of the antioxidant enzymes was also investigated. After incubation for 1 or 48 h, productions of superoxide (by hydroethidine method), nitric oxide (by 4,5-diaminofluorescein diacetate-DAF-2DA assay), insulin (by radioimmunoassay), and expressions (by western blot analysis) of glutathione peroxidase (GPx-1) and gp91PHOX were measured. EPA and DHA reduced superoxide production after 1-h incubation. After 48 h, palmitic acid reduced superoxide production that was normalized by EPA treatment. Palmitic acid increased NO production that was reverted by EPA and DHA. Palmitic acid increased insulin secretion after 48 h, whereas both omega-3 fatty acids increased intracellular insulin content. EPA and DHA enhanced GPx-1 expression as well as gp91PHOX glycosylated form. In conclusion, EPA and DHA increased intracellular insulin content and antioxidant enzymatic defense capacity and decreased pro-oxidant generating activities that are associated with maintenance of pancreatic beta cell redox state in response to palmitic acid (AU)

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Tuberculosis in an autosomal recessive case of chronic granulomatous disease due to mutation of the NCF1 gene

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Tumor necrosis factor-alpha-induced nuclear factor-kappaB activation in human cardiomyocytes is mediated by NADPH oxidase

An elevated level of tumor necrosis factor (TNF)-α is implicated in several cardiovascular diseases including heart failure. Numerous reports have demonstrated that TNF- alfa activates nuclear factor (NF)-kappaB, resulting in the upregulation of several genes that regulate inflammation, proliferation, and apoptosis of cardiomyocytes. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, a major source of reactive oxygen species (ROS), is also activated by TNF- alfa and plays a crucial role in redox-sensitive signaling pathways. The present study investigated whether NADPH oxidase mediates TNF-alfa-induced NF-kappaB activation and NF-kappaB-mediated gene expression. Human cardiomyocytes were treated with recombinant TNF- alfa with or without pretreatment with diphenyleneiodonium (DPI) and apocynin, inhibitors of NADPH oxidase. TNF-α-induced ROS production was measured using 5-(and-6)-chloromethyl-2', 7'-dichlorodihydrofluorescein diacetate assay. TNF- alfa-induced NF-kappaB activation was also examined using immunoblot; NF-kappaB binding to its binding motif was determined using a Cignal reporter luciferase assay and an electrophoretic mobility shift assay. TNF- alfa -induced upregulation of interleukin (IL)-1β and vascular cell adhesion molecule (VCAM)-1 was investigated using real-time PCR and immunoblot. TNF- alfa -induced ROS production in cardiomyocytes was mediated by NADPH oxidase. Phosphorylation of IKK- alfa /β and p65, degradation of IkappaBalfa, binding of NF-kappaB to its binding motif, and upregulation of IL-1β and VCAM-1 induced by TNF- alfa were significantly attenuated by treatment with DPI and apocynin. Collectively, these findings demonstrate that NADPH oxidase plays a role in regulation of TNF- alfa -induced NF-kappaB activation and upregulation of proinflammatory cytokines, IL-1β and VCAM-1, in human cardiomyocytes

Validación de la técnica de dihidrorodamina 123 para el diagnóstico de la enfermedad granulomatosa crónica en Colombia / Validation of the dyhidrorhodamine test for the diagnosis of chronic granulomatous disease in Colombia

Introducción: La enfermedad granulomatosa crónica (EGC) es una inmunodeficiencia primaria por defectos en la explosión respiratoria de los fagocitos cuyas manifestaciones clínicas más frecuentes son los granulomas y las infecciones recurrentes por gérmenes encapsulados. Objetivo Estandarizar en Colombia la técnica de dihidrorodamina (DHR) para diagnóstico de EGC con el propósito de evaluar la explosión respiratoria en neutrófilos y monocitos de sangre periférica (SP) humana después de ser activados in vitro. Métodos Los leucocitos de SP de 10 individuos sanos fueron activados utilizando varias concentraciones de PMA, evaluando la explosión respiratoria por citometría de flujo. Adicionalmente, se obtuvieron los patrones de oxidación de la DHR de estas células en EGC ligada al X, portadoras de este defecto, y en EGC autosómica recesiva. Resultados Las mejores concentraciones de PMA para evaluar el estallido respiratorio tanto en neutrófilos como en monocitos se encontraron entre 0,2 y 5 μg/ml. Se establecieron parámetros de normalidad de la prueba en neutrófilos en nuestra población. Adicionalmente, los patrones de oxidación de la DHR en monocitos no siempre fueron los mismos a aquellos de los neutrófilos. Conclusiones La técnica de DHR por citometría de flujo es un método de cribado que identifica con facilidad, sensibilidad y a bajo costo los diferentes fenotipos de la EGC. Sin embargo, se deben establecer en cada laboratorio los parámetros de normalidad que permiten realizar con certeza la caracterización inicial de esta condición y evaluar diferentes tipos celulares teniendo en cuenta que la expresividad del defecto puede ser específica de ciertas poblaciones celulares (AU)

Introduction: Chronic granulomatous disease (CGD) is a primary immunodeficiency caused by defects in the respiratory burst of phagocytes. Affected patients often suffer from granulomas and recurrent infections, mainly due to encapsulated bacteria. Aim: To standardize the dihydrorhodamine test (DHR) in Colombia used for the diagnosis of CGD by evaluating the respiratory burst in human blood neutrophils and monocytes after in vitro activation. Methods: Phagocyte respiratory burst in peripheral blood samples from 10 healthy controls was evaluated by flow cytometry after leukocyte activation with several concentrations of phorbol myristate acetate (PMA). The different oxidation patterns of DHR in X-linked or autosomal recessive CGD were also obtained. Results: The most suitable concentrations of PMA for the evaluation of the respiratory burst in peripheral blood were 0.2 to 5g/ml. Reference values for this test in neutrophils from our population were established. It was shown that the oxidation patterns of DHR in monocytes were not always identical to those observed in neutrophils. Conclusion: The evaluation of DHR oxidation by flow cytometry is a screening method that easily identifies the different phenotypes of CGD, with good sensitivity and at a lower cost. However, it is crucial that every laboratory establishes its own normal range for this test, in order to achieve the accurate characterization of this condition. DHR oxidation patterns may be also evaluated in different blood cells, since cell type-specific defects have also been reported (AU)

The senescence-accelerated mouse prone-8 (SAM-P8) oxidative stress is associated with upregulation of renal NADPH oxidase system

Herein, we investigate whether the NADPH oxidase might be playing a key role in the degree of oxidative stress in the senescence-accelerated mouse prone-8 (SAM-P8). To this end, the activity and expression of the NADPH oxidase, the ratio of glutathione and glutathione disulfides (GSH/GSSG), and the levels of malonyl dialdehyde (MDA) and nitrotyrosine (NT) were determined in renal tissue from SAM-P8 mice at the age of 1 and 6 months. The senescence-accelerated-resistant mouse (SAM-R1) was used as control. At the age of 1 month, NADPH oxidase activity and Nox2 protein expression were higher in SAM-P8 than in SAM-R1 mice. However, we found no differences in the GSH/GSSG ratio, MDA, NT, and Nox4 levels between both groups of animals. At the age of 6 months, SAM-R1 mice in comparison to SAM-P8 mice showed an increase in NADPH oxidase activity, which is associated with higher levels of NT and increased Nox4 and Nox2 expression levels. Furthermore, we found oxidative stress hallmarks including depletion in GSH/GSSG ratio and increase in MDA levels in the kidney of SAM-P8 mice. Finally, NADPH oxidase activity positively correlated with Nox2 expression in all the animals (r = 0.382, P < 0.05). Taken together, our data allow us to suggest that an increase in NADPH oxidase activity might be an early hallmark to predict future oxidative stress in renal tissue during the aging process that takes place in SAM-P8 mice (AU)

Evaluación de la expresión de la subunidad p22 phox de la NADPH oxidasa (NOX) en cáncer de próstata e hiperplasia prostática benigna: estudio comparativo / Evaluation of the expression of p22 phox subunit of NADPH oxidase (NOX) in prostate cancer and benign prostatic hyperplasia: A comparative study

Introducción y objetivo: Recientes reportes ubican que el cáncer de próstata es el segundo cáncer más común y la segunda causa principal de muerte por cáncer en los hombres. Métodos y resultados: Se obtuvieron 62 muestras (30 de pacientes con cáncer y 32 de pacientes con hiperplasia) colectadas desde enero de 2004 a diciembre de 2007. Se llevó a cabo un estudio clínico, experimental, transversal, comparativo y descriptivo. Se cumplieron los criterios de inclusión (diagnóstico de cáncer o hiperplasia), exclusión (pacientes que no autorizaron a participar en el estudio o no candidatos a la resección prostática) y de eliminación (tejidos dañados). Se detectó por inmunohistoquímica la presencia de la subunidad p22 phox de la NADPH oxidasa en pacientes con cáncer de próstata e hiperplasia prostática a partir de la formación del complejo avidina-biotina en presencia de diaminobenzidina como colorante de contraste. El análisis estadístico fue determinado con la prueba t de student (software Graph Prism 3.0) considerando una p<0,05 para diferencias estadísticas. Los resultados de la inmunorreactividad de p22 phox en estroma y glándula de la próstata mostraron un incremento en el cáncer de próstata (8,45±3,6 y 25,08±7,5% p<0,0001, respectivamente) en comparación con los resultados encontrados para hiperplasia prostática (4,8±2,8 y 6,7±3,1% p<0,0001, respectivamente). Conclusiones: La sobreexpresión de NADPH oxidasa se encuentra involucrada en el cáncer de próstata. Además, sugerimos que la NADPH oxidasa, en combinación con otros marcadores clásicos, podría funcionar como un indicador para el monitoreo postoperatorio de pacientes diagnosticados con hiperplasia u otras patologías menores de la próstata (AU)

Introduction and objective: Recent reports found that prostate cancer is the second most common cancer and second leading cause of cancer death in men. Methods and results: 62 samples were obtained (30 of patients with cancer and 32 of patients with hyperplasia) collected from January 2004 to december 2007. Was conducted a clinical, experimental, transversal, comparative and descriptive trial. Were followed the inclusion (cancer or hyperplasia diagnosis), exclusion (patients not authorized to participate in the study or not candidates for resection of prostate) and elimination (damage tissue) criteria. Was detected by immunohistochemistry the presence of p22 phox NADPH oxidase subunit in patients with prostate cancer and prostatic hyperplasia from the formation of avidin-biotin complex using diaminobenzidine as a dye contrast. The statistical analysis was determined with t test (Graph Prism 3.0 software) considering p<0.05 for statistical differences. The results of the immunoreactivity of p22 phox in the stroma and gland of the prostate showed an increase in prostate cancer (8.45±3.6 and 25.08±7.5% p<0.0001, respectively) in comparison with the results for prostatic hyperplasia (4.8±2.8 and 6.7±3.1% p<0.0001, respectively). Conclusions: The over-expression of the NADPH oxidase is involved in the prostate cancer. Moreover, we suggested that the NADPH oxidase, in combination with other classical markers, could be an indicator for the post-treatment monitoring of the patients diagnosed with hyperplasia and others minors pathologies of the prostate (AU)

Genotype of the CYBA promoter − 930A/G, polymorphism C677T of the MTHFR and APOE genotype in patients with hypertensive disorders of pregnancy: An observational study

Background and objective. Hypertensive disorders of pregnancy could be favoured by polymorphisms in genes affecting vascular physiology. The aim of our work was to study several variants in the genes regulating oxidative stress, plasma lipids metabolism and endothelial function (observational study). Material and methods: We studied the −930A/G polymorphism of the CYBA gene promoter, the apolipoprotein E (APOE) genotype and the methylene-tetrahydrofolate reductase (MTHFR) gene C677T polymorphism in 134 healthy pregnant women, 266 pregnant with non-proteinuric hypertension (NPH) and 184 patients with preeclampsia (PE). Results: The GG genotype of the CYBA gene promoter was present in 32.1% of the control population, 38.7% of patients with NPH (P=0.19) and 21.2% of the women with PE (P=0.03). A higher frequency of ∈3/∈4 and ∈4/∈4 genotypes of APOE was observed in patients with PE or NPH compared with controls (P<0.01). There were no significant differences detected in genotype or allele distribution of the MTHFR, C677T polymorphism. APOE ∈3/∈4 and ∈4/∈4 genotypes had a worse lipoprotein profile characterized by higher plasma values of total cholesterol (P<0.05) and triglycerides (P<0.005). Despite no differences in MTHFR C677T polymorphism distribution, higher levels of plasma homocysteine were observed in patients with PE than in patients with NPH or controls. Conclusions: CYBA and APOE polymorphism showed a different distribution in the groups studied, while no differences were observed in MTHFR C677T polymorphism. APOE genotype was associated with changes in lipid and lipoprotein profiles in pregnant women (AU)

Fundamento y objetivo: Nos propusimos valorar en un estudio observacional si algunos polimorfismos en genes que regulan el estrés oxidativo, los niveles de homocisteina y el metabolismo de los lípidos, podrían predisponer a diferentes trastornos hipertensivos del embarazo. Material y métodos: Estudiamos el polimorfismo −930A/G del gen promotor del CYBA, el genotipò de la apolipoproteína E (ApoE) y el polimorfismo C677T del gen de la metilen tetrahidrofolato-reductasa (MTHFR) en 134 embarazadas sanas, 266 embarazadas con hipertensión no proteinurica (HNP) y 184 pacientes con preeclampsia (PE). Resultados: El genotipo GG del promotor del gen del CYBA estuvo presente en el 32,1% de la población de control, en el 38,7% de las pacientes con HNP (p=0,19) y el 21,2% de las mujeres con PE (p=0,03). Los pacientes con PE o HNP, en comparación con los controles, mostraron una mayor frecuencia de genotipos ∈3/∈4 y ∈4/∈4 (p<0,01). No hubo diferencias significativas en la distribución por genotipos del polimorfismo C677T del gen de la MTHFR. Los genotipos ∈3/∈4 y ∈4/∈4 de la ApoE mostraron un peor perfil lipoproteico caracterizado por un aumento de colesterol total (p<0,05) y triglicéridos (p<0,005). A pesar de no haber diferencias en la dsitribución de la mutación C677T del gen de la MTHFR, se observó un aumento de los niveles de homocisteína plasmática en los pacientes con PE. Conclusiones: Los polimorfismos del gen del CYBA y de la ApoE mostraron una distribución diferente en los grupos estudiados que no se observó en el prolimorfismo C677T del gen MTHFR (AU)

G allele of the –930A>G polymorphism of the CYBA gene is associated with insulin resistance in obese subjects

It has been shown that NADPH oxidase plays a role in oxidative stress which hasbeen involved in the development of metabolic syndrome. The –930A/G polymorphismof the CYBA gene (that codes p22phox, a major component of the NADPHoxidase) has been associated with human hypertension and with a reduction inNADPH oxidase activity. In this work, we have examined the influence of the–930A/G polymorphism on obesity risk and insulin resistance in a case-controlstudy of Spanish subjects (n=313). In the obese group (n=159), there was a statisticallysignificant association between the GG genotype of the –930A/G polymorphismof the CYBA gene and fasting insulin levels and HOMA index. This outcomeagrees with previous findings concerning functional analyses of this polymorphismand reinforces the hypothesis that insulin resistance is associated with oxidativestress. In conclusion, a protective effect in carriers of the –930A/G polymorphism ofthe p22phox gene against insulin resistance in a population of Spanish obese adultshas been found (AU)

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Estallido respiratorio de los fagocitos / Phagocyte respiratory burst

El estallido respiratorio de los fagocitos, producido por la NADPH-oxidasa, complejo enzimático que cataliza la formación de radical superóxido, constituye una de las fuentes endógenas más importantes de especies reactivas del oxígeno en el organismo. Este sistema comprende un complejo flavocitocromo b558 unido a membrana, y factores citosolicos p47phox, p67phox, p40phox y la pequeña GTPasa Rac2, que se trastocan a la membrana plasmática donde experimentan un proceso de ensamblaje que conforma el sistema enzimático activo. El conocimiento de las interacciones proteina-proteína que permiten el ensamblaje y el mecanismo de acción enzimático, ha permitido detectar los cambios que transcurren en el estado activo. La importancia de la NADPH oxidasa se muestra en la enfermedad granulomatosa crónica, patología transmitida por herencia, en la cual un componente de la NADPH oxidasa está ausente o defectivo. Tales individuos padecen infecciones recurrentes crónicas y severas debido a la incapacidad de sus neutrófilos para destruir microbios

The phagocyte respiratory burst produced by the NADPH oxidase, enzyme complex which catalyzes the production of superoxide radical, is one of the main endogenous sources of reactive oxygen species in the body. NADPH oxidase consists of a membrane-bound flavocytochrome b558 complex, and cytosolic factors p47phox, p67phox, p40phox and the small GTPase Rac, which translocate to the membrane to assemble the active complex following cell activation. A great deal of current research involves understanding the protein protein interactions involved in the assembly and enzyme mechanism and how these change with the activation state. The importance of the NADPH oxidase is illustrated by the inherited condition Chronic Granulomatous Disease in which a component of the respiratory burst oxidase is absent or defective. Affected individuals suffer from recurrent, chronic and severe infections due to the inability of their neutrophils to kill microbes

C) Estrés oxidativo en la hipertensión: de los SNPs al fenotipo clínico / No disponible

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Nutrient regulation of Beta cells NADPH-oxidase activity

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Papel de la NAD(P)H oxidasa en la hipertensión arterial, conespecial énfasis en los aspectosgenéticos

El aumento en la producción de especies reactivas del oxigeno, especialmente el anión superóxido, contribuye significativamente en las alteraciones funcionales y estructurales características de la hipertensión. Un aumento en la producción de anión superóxido conlleva una disminución en la biodisponibilidad del oxido nítrico como consecuencia de una reacción oxidativa que lo inactiva. Unos niveles elevados de anión superóxido junto con una baja biodisponibilidad del óxido nítrico conducen a la disfunción endotelial de la pared vascular y a una hipertrofia de las células vasculares. La principal fuente de anión superóxido en la pared vascular es la NAD(P)H oxidasa, y son ya numerosos los trabajos que muestran que un aumento en la producción de anión superóxido resultado de la activación de esta enzima se encuentra asociado con el desarrollo de la hipertensión. Esta oxidasa está regulada por una gran variedad de estímulos entre los cuales encontramos factores vasoactivos, factores de crecimiento y citoquinas. Recientemente, nuevos estudios han demostrado la importancia que las alteraciones genéticas pueden desempeñar en la regulación de los componentes de este sistema enzimático. La existencia de polimorfismos en uno de los componentes críticos de esta oxidasa, la subunidad p22phox, afecta a la actividad de esta enzima, y abre las puertas a nuevas investigaciones que conduzcan a la identificación de marcadores genéticos de estrés oxidativo en la hipertensión (AU)