Disfunção endotelial na insuficiência cardíaca / Endothelial dysfunction in heart failure

Insuficiência cardíaca é caracterizada, dentre outrosaspectos, por vasoconstrição periférica secundária à ativaçãoneuro-hormonal e alteração da função endotelial. O endotélioregula a homeostase vascular e, nesse contexto, o óxido nítricose destaca devido sua importância quanto à promoção devasodilatação, inibição da ativação plaquetária, inibição daagregação dos monócitos ao endotélio e inibição da proliferaçãoanormal da musculatura lisa vascular, Está bem demonstradona literatura médica que, nos portadores de insuficiência cardíaca,a disfunção endotelial ocorre com frequência e, quandopresente, provoca significativo impacto prognóstico negativo.No entanto, a disfunção endotelial melhora consideravelmentecom o tratamento clínico...

Heart failure is characterized by peripheral vasoconstrictiondue to neuro hormonal activation and alteration of endothelialfunction. The endothelium regulates vascular homeostasis,nitric oxide stands out, owing its importance as promotingvasodilation, inhibition of platelet activation, aggregationinhibition of monocytes to endothelium and inhibiting theabnormal proliferation of vascular smooth muscle. It is welldemonstrated in the literature that in heart failure patients,endothelial dysfunction occurs frequently and when presentit leads to a significant negative prognostic impact, however,considerable improvement occurs when clinical treatment isapplied...

In vitro antioxidant activity of roots of Thespesia lampas Dalz and Gibs

The free radical scavenging potential of roots of Thespesia lampas Dalz and Gibs was studied by different antioxidant models. Free radicals are implicated for more than 80 diseases including Diabetes mellitus, arthritis, cancer, ageing etc. In the treatment of theses diseases, antioxidant therapy has gained an utmost importance. Current research is directed towards finding naturally occurring antioxidant of plant origin. In Indian system of medicine, Thespesia lampas is an important medicinal plant and its root juice has been used in various ailments and as health tonic. To understand the mechanisms of pharmacological actions, the in vitro antioxidant activity of aqueous extract of Thespesia lampas was investigated for the activity of scavenging superoxide anion radicals, nitric oxide radical and lipid peroxidation assay. In all the testing, a significant correlation existed between concentrations of the extract and percentage inhibition of free radicals, metal chelating, reducing power or inhibition of lipid peroxidation. These results clearly indicate that Thespesia lampas is effective against free radical mediated diseases

The Protective Effects of Green Tea Extract against L-arginine Toxicity to Cultured Human Mesangial Cells

The aim of this study was to investigate whether green tea extract (GTE) has the protective effects on excess L-arginine induced toxicity in human mesangial cell. Human mesangial cells treated with L-arginine were cultured on Dulbecco's modified eagle medium in the presence and absence of inducible nitric oxide synthase (iNOS) inhibitor and GTE. The cell proliferation was determined by 3 (4,5-dimethylthiazol- 2-yl)-2, 5-diphengltetrqzolium bromide, a tetrazole assay. The iNOS mRNA and its protein expression were detected by reverse transcription polymerase chain reaction and Western blot, respectively. The concentration of nitric oxide (NO) was measured by NO enzyme-linced immuno sorbent assay kit. L-arginine significantly inhibited the proliferation of human mesangial cells, and induced the secretion of NO to the media. NO production by L-arginine was significantly suppressed by GTE and iNOS inhibitor (p<0.01). The expression level of iNOS mRNA and its protein that was significantly increased by L-arginine was decreased by iNOS inhibitor but not by GTE. GTE protected the mesangial cells from the NO-mediated cytotoxicity by scavenging the NO rather than by iNOS gene expression. Therefore, we conclude that GTE has some protective effect for renal cells against oxidative injury possibly by polyphenols contained in GTE.

Evaluation of free radical scavenging activity of Butea monosperma Lam.

In the present study, ethyl acetate, butanol and aqueous fractions derived from total methanol extract of Butea monosperma flowers were evaluated for radical scavenging activities using different in vitro models like reducing power assay, scavenging of 2,2 diphenyl-1-picrylhydrazyl (DPPH) radical, nitric oxide radical, superoxide anion radical, hydroxyl radical and inhibition of erythrocyte hemolysis using 2, 2' azo-bis (amidinopropane) dihydrochloride (AAPH). Methanol extract along with its ethyl acetate and butanol fractions showed potent free radical scavenging activity, whereas aqueous fraction was found to be devoid of any radical scavenging properties. The observed activity could be due to the higher phenolic content in the extracts (16.1, 25.29, and 17.74% w/w in methanol extract, ethyl acetate and butanol fractions respectively). HPTLC fingerprint profile of the ethyl acetate and butanol fractions were developed which would serve as reference standard for quality control of the extracts.

Peroxynitrite: a potent oxidizing and nitrating agent.

Nitric oxide (NO*) reacts with superoxide (O2-*) forming peroxynitrite (PXN) (ONOO-), a strong oxidant which reacts with several biomolecules leading to enormous implications in biological process, holds enormous implications for the understanding of free radicals. The ONOO- formation in vivo has significant implications in free radical biology. It exerts a defensive role in large number of pathophysiological reactions and also acts as signaling molecule in activation of several protooncogenes. It decomposes rapidly to an intermediate and reacts with several biomolecules. Evidence for PXN formation in vivo has been obtained immunohistochemically through detection of a characteristic reaction product with protein tyrosine residues and 3-nitrotyrosine. This "biomarker" of PXN formation has now been identified in various pathologies such as Lou Gehrig's disease, Parkinson's disease, cancer, atherosclerosis as well as in biological aging. 3-nitrotyrosine formation has been documented in various tissues, e.g. even in non-diseased embryonic heart during normal development. Therefore, there is a great opportunity in the postgenomic period to understand the interplay of these molecular interactions with biological events such as apoptosis, gene regulation etc. This review deals with biological significance of peroxynitrite, its precursors, reactions with large range of biomolecules, including aminoacids, proteins, lipids, nucleic acids, antioxidants as well as cytotoxic aspects.

Generation of Nitric Oxide in the Opossum Lower Esophageal Sphincter during Physiological Experimentation

Lipopolysaccharide (LPS), given in vivo, modulates opossum esophageal motor functions by inducing the inducible nitric oxide synthase (iNOS), which increases nitric oxide (NO) production. Superoxide, a NO scavenger, is generated during this endotoxemia. Superoxide is cleared by superoxide dismutase (SOD) and catalase (CAT) to protect the physiological function of NO. This study examined whether lower esophageal sphincter (LES) motility, NO release, and iNOS and nitrotyrosine accumulation in the LES are affected by LPS in vitro. Muscle strips from the opossum LES were placed in tissue baths containing oxygenated Krebs buffer. NO release was measured with a chemiluminescence NOx analyzer, and Western blots were performed to analyze iNOS and nitrotyrosine production. The percent change in resting LES tone after a 6-hour exposure to LPS was significantly increased compared to pretreatment values. The percent LES relaxation upon electrical stimulation was significantly decreased in the control group at 6 hours, indicating that the LPS treatment had an effect. The NO concentration in the tissue bath of LPS-treated muscle without nerve stimulation was significantly less than that of LPS treatment combined with SOD/CAT or SOD/CAT alone. iNOS and nitrotyrosine were detectable and increased over time in the LES muscle of both the control and LPS-treated groups. Antioxidant enzymes may play a role in regulating NO-mediated neuromuscular functions in the LES.

Structure and secretory activity of cultured chondrocytes from patients with osteoarthritis

Cartilage samples were taken from OA patients in order to describe and quantify pro-inflammatory mediators. Samples were cultured under aseptic conditions in Dulbecco's modified Eagle medium at 37°C for 10 days. Control samples, taken from non-inflammatory cartilage, were cultured under the same conditions. The levels of NO-2 and NO-3 were measured in the supernatant using a spectrophotometric assay. The activity of MMP-1 was quantified by ELISA.The concentration of NO-x was 47.3 ± 4.1 µM in the OA cartilague and 10.7 ± 1.8 µM in the controls. The average MMP-1 activity was 3,650 ± 387 ng/ml in the OA cartilage and 2,150 ± 190 ng/ml in the control samples. These increased values of MMP-1 and NO- x observed in the OA cartilage suggest a higher catabolic activity. A morphological analysis of OA chondral tissue using light microscopy shows that the surface of the tissue is characterized by the presence of aggregated chondrocytes or "clones" but in the deeper areas isolated cells are found. These results could be a significant contribution towards the identification of biological markers indicating the presence of OA activity

Effect of cholesterol and 7-beta hydroxycholesterol on glutathione status and nitric oxide production in murine peritoneal macrophages.

Present study was conducted to observe the effect of cholesterol and oxidized cholesterol (7beta-hydroxycholesterol,7beta-OH) on the nitric oxide (NO) production and the redox ratio by lipopolysaccharide-stimulated macrophages. Dose-dependent decrease in NO levels was seen with both cholesterol and 7beta-OH at different incubation intervals (6,12,18,24 hr) and concentrations (2.5,5,7.5microg/ml). On comparison, a significant decrease in the NO was observed at 24 hr interval in 7beta-OH exposed cells with all respective concentrations of cholesterol. Incubation with 7beta-OH also resulted in significant increase in levels of oxidized glutathione (GSSG) and decrease in reduced glutathione (GSH), while cholesterol showed no effect on GSSG levels. Moreover, GSH levels were lowered only at highest concentration (7.5microg/ml), and at longer incubation intervals (18,24 hr) with cholesterol exposure. This altered the redox status in both cholesterol/7beta-OH treated macrophages. Increased redox ratio and decreased NO levels indicated increased oxidative stress and decreased vasodilation by 7beta-OH compared to cholesterol.

Extract of gum resins of Boswellia serrata L. inhibits lipopolysaccharide induced nitric oxide production in rat macrophages along with hypolipidemic property.

Boswellia serrata, Linn F (Burseraceae) is commonly used in Indian system of medicine (Ayurvedic) as an anti-inflammatory, analgesic, anti-arthritic and anti-proliferative agent. This study was planned to investigate the water-soluble fraction of the oleoresin gum of Boswellia serrata (BS extract) on lipopolysaccharide (LPS) induced nitric oxide (NO) production by macrophages under in vivo and in vitro conditions. In the previous condition, rats were fed on atherogenic diet (2.5% cholesterol, 1% cholic acid, 15.7 % saturated fat) along with the BS extract for 90 days. Blood was collected for lipid profile and toxicological safety parameters. Peritoneal macrophages were isolated and cultured to see the LPS induced NO production. Under in vivo experiment, BS extract significantly reduced serum total cholesterol (38-48 %), increased serum high-density lipoprotein- cholesterol (HDL-cholesterol, 22-30%). Under in vitro experiments with thioglycolate activated macrophages, it inhibited LPS induced (NO) production with IC 50 value at 662 ng /ml. Further, this fraction, in the dose of 15 mg/100 g body wt for 90 days, did not show any increase in serum glutamate-pyruvate transaminase (SGPT) and blood urea, in normal control animals. However, it significantly reversed the raised SGPT and blood urea in the atherogenic diet-fed animals. Transverse section of liver and kidney also supported its protective effect. Thus it may be concluded that water extract of Boswellia serrata possesses strong hypocholesterolemic property along with increase in serum HDL. It inhibits the LPS induced NO production by the activated rat peritoneal macrophages and show hepato-protective and reno-protective property.

Citotoxidade dos cimentos endodônticos topseal e sealer 26 em culturas de macrófagos: avaliação da produção de óxido nítrico / Citotoxicity of topseal and sealer 26 endodontic cements in macrophage culures: nitric oxide production assesment

Avaliou-se a produção de óxido nítrico em cultura de macrófagos peritoneais de camundogos Swiss, frente a dois cimentos endodonticos um à base de resina epóxica, Topseal e outro à base de hidróxido de calcio, Sealer 26. Após a proporção, espatulação, presa e pulverização, alíquotas de 100ml da suspensão contendo 9mg/mL dos respetctivos cimentos foram adicionados em placa de cultura de tecido de 96 orifícios, contendo cultura de macrófagos a 5,0X10 a sexta células/ml. Após 48 horas de incubação, a 37°C, em 5 por cento de CO2, determinou-se a concentração de óxido nítrico no leitor ELISA automático. Para o cimento Topseal, a produção de óxido nítrico variou de 76,5 a 113,6umols enquento para o Sealer 26 os valores variaram de 55,8 a 243,3umols. Por conseguinte, mediante a produção de óxido nítrico, o Sealer 26 causou, significativamente, maior toxicidade aos macrófagos.

Biología molecular y funcional del óxido nítrico / Molecular and functional biology of the nutric oxide

La intervención del monóxido del nitrógeno comúnmente llamado óxido nítrico en numerosas funciones del organismo, hacen que el conocimiento de este tema obtenga una importancia para el estudio y comprensión del metabolismo. Se abordan las características fisicoquímicas, las síntesis y sus funciones. Se exponen además eventos relacionados con el daño celular a través de las especies reactivas del oxígeno que origina

El óxido nítrico: implicaciones fisiopatológicas en la preeclampsia / Nitric oxide: physiopathological implications in pre-eclampsia

Se hizo una revisión de la preeclampsia, uno de los problemas de salud más significativos en el embarazo humano, que complica aproximadamente de 6 a 8 por ciento de los embarazos y además causa retardo del crecimiento fetal, morbilidad y mortalidad infantil, nacimientos prematuros y muerte materna. Estudios recientes han reportado que hay un desbalance en el status oxidativo, aumentados los sistemas oxidantes y los sistemas antioxidantes disminuidos en mujeres con preeclampsia y que este factor pudiera contribuir a la patogénesis de esta enfermedad. El óxido nítrico es un factor vasodilatador y antiagregante plaquetario que puede desempeñar un papel importante al inducir cambios hemodinámicos durante el embarazo. Se trató acerca de la bioquímica del óxido nítrico y sus posibles interacciones con otros radicales libres. Estudios en ratas muestran que el embarazo está asociado con un aumento en la producción y respuesta al óxido nítrico. En humanos se han encontrado contradicciones acerca del papel del óxido nítrico en la adaptación materna al embarazo. Esto sugiere que el óxido nítrico, puede ser uno de los múltiples sistemas que actúan en el mantenimiento de la relación simbiótica entre la madre y el feto. Sin embargo la función de cada sistema puede estar determinada genéticamente

Assessment of nitric oxide in induced sputum of asthmatic patients and its prognostic significance in monitoring allergic inflammation

Nitric oxide [NO] plays an important role as an inflammatory mediator in the airways. However, because direct measurement of endogenous NO has been difficult in vivo, the exact pathologic role of NO in bronchial asthma has remained unclear. To study the levels of nitric oxide derivatives in induced sputum of asthmatic patients in order to assess their clinical utility as non-invasive prognostic indicator for monitoring the degree of airway inflammation in asthmatics. We examined the concentration of stable end products of NO, namely nitrite and nitrate in hypertonic saline-induced sputum in 25 patients with different grades of bronchial asthma among whom 12 patients were examined before and after anti-asthmatic medications including steroid preparations. Ten normal age and sex-matched subjects were included as controls. Patients were 14 males and 11 females aged 36.6 +/- 8.7 years. They included 11 patients with severe asthma, 7 with moderate asthma and 7 with mild asthma. Fresh expectorated sputum was treated with equal volume of dithiothreitol 0.1%, cytospinned for cell count, and the supernatant was collected for biochemical assay. Measurement of NO derivatives in induced sputum was carried out colorimetrically by using modified Griess reaction. We evaluated the relationship between levels of NO derivatives and percentages of eosinophils, epithelial shedding in induced sputum and the degree of airway obstruction measured by pulmonary functions [forced expiratory volume in one second [FEV1]/forced vital capacity [FVC]] in asthmatic patients. The concentration of NO derivatives in induced sputum was significantly higher in patients with asthma than in normal control subjects [1126 +/- 134.3 micro mol/L versus 567 +/- 98.4 micro mol/L; P <0.01]. According to asthma severity, severe and moderate asthmatic patients had higher levels of NO derivatives [1261 +/- 193.2 and 1037 +/- 156.3micro mol/L, respectively] in induced sputum as compared to mild asthmatic patients [786 +/- 89.5 micro mol/L] [P < 0.01]. Percentages of eosinophils in induced sputum were also significantly higher in asthmatic patients than controls [35.6 +/- 4.7% vs 1.3 +/- 0.2%, P<0.01]. There were significant positive correlations between NO derivatives levels and percentages of each of eosinophils and shedding epithelial cells in induced sputum in asthmatic patients [r[S]=0.58, P <0.01; r[S]=0.62, P<0.01, respectively]. A significant negative correlation was found between NO derivatives levels and the ratio of FEV1/FVC [r[S]= -0.63, P<0.01], that's to say NO derivatives levels correlated positively with the degree of airway obstruction in asthmatic patients. The levels of NO derivatives and percentages of eosinophils in induced sputum were reduced significantly in asthmatic patients following treatment with corticosteroids [P<0.05]. These findings confirmed that the level of NO derivatives was increased in the tracheobronchial secretion of asthmatic patients and was parallel with the severity of asthma. Hence, measurement of NO derivatives in induced sputum could be used as a non-invasive prognostic biochemical marker for assessing the degree of airway inflammation and monitoring the anti-inflammatory treatment response in asthmatic patients

Oxido nítrico: un gas contaminante con propiedades biológicas: su importancia en fisiopatología cardiovascular / Nitric oxide, a contamining gas with biological properties

Se revisa la fisicoquímica y la biología del óxido nítrico (NO), una molécula inorgánica antes conocida como factor relajante derivado del endotelio (EDRF). Los descubridores de sus propiedades biológicas fueron galardonados con el premio Nobel de Medicina en 1998. NO se forma de la L-arginina por acción de la NO sintetasa (NOS), tiene una vida media muy corta y ejerce una acción paracrina en las inmediaciones del sitio en que se produce. Su mecanismo consiste en la activación de la guanilato ciclasa (GC) con aumento de cGMP intracelular, lo que desencadena mecanismos de transducción distintos en los diversos órganos y sistemas. En el aparato cardiovascular interviene en la homeostasis de la circulación e impide la agregación de plaquetas y leucocitos. Se compara NO endógeno del endotelio con NO exógeno de los nitrovasodilatadores. En el sistema nervioso central NO participa en la plasticidad sináptica, favoreciendo aprendizaje y memoria; en el sistema nervioso autónomo es el neurotransmisor de nervios no adrenérgicos no colinérgicos (NANC), por ello llamados también "nitrérgicos". NO ejerce un doble papel: es una señal intercelular de acción citoprotectora y es una molécula citotóxica de la respuesta inmunitaria inespecífica. Su disregulación se ha asociado a distintos procesos patológicos entre los que destacan: aterogénesis, hipertensión, enfermedad coronaria, síndromes isquémicos, miocardiopatías, enfermedad de Alzheimer y otros procesos neurodegenerativos, susceptibilidad a infecciones, enfermedades autoinmunes, desarrollo de tumores e impotencia. El entendimiento de la físiopatología de NO abre nuevos campos terapéuticos para éstos y otros procesos patológicos.

The double action of nitric oxide on free radical-mediated oxidations

Nitric oxide (.NO) is a free radical species synthesized by the oxidation of the amino acid L-arginine to citrulline, by the action of the enzyme nitric oxide synthase (NOS). Nitric oxide has been recognized as a key mediator of diverse physiological functions by direct interactions with critical biomolecules. In addition, nitric oxide can up- or downregulate biological oxidations and therefore modulate free radical mediated injury. Nitric oxide reaction with superoxide radical (O2.-) leads to the formation of a strong oxidizing and cytotoxic molecule, peroxynitrite anion (ONOO-). Peroxynitrite is a much stronger oxidant than any of its precursors being capable of oxidizing and/or nitrating a significant number of biomolecules including protein and nonprotein thiols, different amino acids, lipids and DNA; it has been shown that peroxynitrite is cytotoxic against bacteria, parasite and mammalian cells and has been proposed to participate in various pathological states. On the other hand, nitric oxide can also inhibit free radical reactions by a series of different mechanisms at the molecular level. Nitric oxide can bind to iron and inhibit metal-mediated free radical chemistry, it can terminate free radical processes via combination reactions with free radical intermediates and it can cause redirection of superoxide-mediated toxicity. The dual role of nitric oxide in free radical-mediated oxidations is clearly demonstrated in the oxygen radical-mediated lipid oxidation model, where low fluxes of nitric oxide promete lipid oxidation via formation of the reactive peroxynitrite while under excess nitric oxide, lipid peroxidation reactions are inhibited due to termination reactions between nitric oxide and lipid radicals.

La inmunidad celular y la vacunación contra la leishmaniasis cutánea / Tha cellular immunity and vaccination against cutaneous leishmaniesis

Revisión de la inmunoterapia de la leishmaniasis, los modelos en los animales de laboratorio, y los progresos recientes en la vacunación experimental. En los últimos años se han producido progresos importantes que han contribuido sustancialmente a clasificar el papel de las interleucinas y otros mediadores químicos en la respuesta inmunitaria. Todos estos hallazgos abren la puerta para la producción de vacunas mejores y más inmunogénicas que en un futuro cercano habrán de utilizarse ventajosam,ente en los humanos