RESUMO
Several physiological processes in the CNS are regulated by the endocannabinoid system (ECS). Cannabinoid receptors (CBr) and CBr agonists have been involved in the modulation of the N-methyl-D-aspartate receptor (NMDAr) activation. Glutaric (GA), 3-hydroxyglutaric (3-OHGA), methylmalonic (MMA) and propionic (PA) acids are endogenous metabolites produced and accumulated in the brain of children affected by severe organic acidemias (OAs) with neurodegeneration. Oxidative stress and excitotoxicity have been involved in the toxic pattern exerted by these organic acids. Studying the early pattern of toxicity exerted by these metabolites is crucial to explain the extent of damage that they can produce in the brain. Herein, we investigated the effects of the synthetic CBr agonist WIN 55,212-2 (WIN) on early markers of GA-, 3-OHGA-, MMA- and PA-induced toxicity in brain synaptosomes from adult (90-day-old) and adolescent (30-day-old) rats. As pre-treatment, WIN exerted protective effects on the GA- and MMA-induced mitochondrial dysfunction, and prevented the reactive oxygen species (ROS) formation and lipid peroxidation induced by all metabolites. Our findings support a protective and modulatory role of cannabinoids in the early toxic events elicited by toxic metabolites involved in OAs.
Assuntos
Ácidos Acíclicos/metabolismo , Ácidos Acíclicos/toxicidade , Erros Inatos do Metabolismo dos Aminoácidos/metabolismo , Benzoxazinas/farmacologia , Encefalopatias Metabólicas/metabolismo , Encéfalo/metabolismo , Agonistas de Receptores de Canabinoides/farmacologia , Glutaril-CoA Desidrogenase/deficiência , Morfolinas/farmacologia , Naftalenos/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Animais , Encéfalo/efeitos dos fármacos , Glutaratos/metabolismo , Glutaratos/toxicidade , Glutaril-CoA Desidrogenase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Ácido Metilmalônico/metabolismo , Ácido Metilmalônico/toxicidade , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Propionatos/metabolismo , Propionatos/toxicidade , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismoRESUMO
The brain of children affected by organic acidemias develop acute neurodegeneration linked to accumulation of endogenous toxic metabolites like glutaric (GA), 3-hydroxyglutaric (3-OHGA), methylmalonic (MMA) and propionic (PA) acids. Excitotoxic and oxidative events are involved in the toxic patterns elicited by these organic acids, although their single actions cannot explain the extent of brain damage observed in organic acidemias. The characterization of co-adjuvant factors involved in the magnification of early toxic processes evoked by these metabolites is essential to infer their actions in the human brain. Alterations in the kynurenine pathway (KP) - a metabolic route devoted to degrade tryptophan to form NAD(+) - produce increased levels of the excitotoxic metabolite quinolinic acid (QUIN), which has been involved in neurodegenerative disorders. Herein we investigated the effects of subtoxic concentrations of GA, 3-OHGA, MMA and PA, either alone or in combination with QUIN, on early toxic endpoints in rat brain synaptosomes. To establish specific mechanisms, we pre-incubated synaptosomes with different protective agents, including the endogenous N-methyl-d-aspartate (NMDA) receptor antagonist kynurenic acid (KA), the antioxidant S-allylcysteine (SAC) and the nitric oxide synthase (NOS) inhibitor nitro-l-arginine methyl ester (l-NAME). While the incubation of synaptosomes with toxic metabolites at subtoxic concentrations produced no effects, their co-incubation (QUIN+GA, +3-OHGA, +MMA or +PA) decreased the mitochondrial function and increased reactive oxygen species (ROS) formation and lipid peroxidation. For all cases, this effect was partially prevented by KA and l-NAME, and completely avoided by SAC. These findings suggest that early damaging events elicited by organic acids involved in metabolic acidemias can be magnified by toxic synergism with QUIN, and this process is mostly mediated by oxidative stress, and in a lesser extent by excitotoxicity and nitrosative stress. Therefore, QUIN can be hypothesized to contribute to the pathophysiology of brain degeneration in children with metabolic acidemias.
Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/metabolismo , Encefalopatias Metabólicas/metabolismo , Encéfalo/metabolismo , Glutaratos/metabolismo , Glutaril-CoA Desidrogenase/deficiência , Ácido Quinolínico/metabolismo , Sinaptossomos/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Modelos Animais de Doenças , Glutaratos/toxicidade , Glutaril-CoA Desidrogenase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Ácido Metilmalônico/metabolismo , Ácido Metilmalônico/toxicidade , Fármacos Neuroprotetores/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Propionatos/metabolismo , Propionatos/toxicidade , Ácido Quinolínico/toxicidade , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Sinaptossomos/efeitos dos fármacosRESUMO
The endocannabinoid system (ECS) is involved in a considerable number of physiological processes in the Central Nervous System. Recently, a modulatory role of cannabinoid receptors (CBr) and CBr agonists on the reduction of the N-methyl-d-aspartate receptor (NMDAr) activation has been demonstrated. Quinolinic acid (QUIN), an endogenous analog of glutamate and excitotoxic metabolite produced in the kynurenine pathway (KP), selectively activates NMDAr and has been shown to participate in different neurodegenerative disorders. Since the early pattern of toxicity exerted by this metabolite is relevant to explain the extent of damage that it can produce in the brain, in this work we investigated the effects of the synthetic CBr agonist WIN 55,212-2 (WIN) and other agonists (anandamide or AEA, and CP 55,940 or CP) on early markers of QUIN-induced toxicity in rat striatal cultured cells and rat brain synaptosomes. WIN, AEA and CP exerted protective effects on the QUIN-induced loss of cell viability. WIN also preserved the immunofluorescent signals for neurons and CBr labeling that were decreased by QUIN. The QUIN-induced early mitochondrial dysfunction, lipid peroxidation and reactive oxygen species (ROS) formation were also partially or completely prevented by WIN pretreatment, but not when this CBr agonist was added simultaneously with QUIN to brain synaptosomes. These findings support a neuroprotective and modulatory role of cannabinoids in the early toxic events elicited by agents inducing excitotoxic processes.
Assuntos
Encéfalo/efeitos dos fármacos , Agonistas de Receptores de Canabinoides/farmacologia , Fármacos Atuantes sobre Aminoácidos Excitatórios/toxicidade , Mitocôndrias/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ácido Quinolínico/toxicidade , Animais , Ácidos Araquidônicos/farmacologia , Benzoxazinas/farmacologia , Encéfalo/fisiopatologia , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Células Cultivadas , Cicloexanóis/farmacologia , Endocanabinoides/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Peroxidação de Lipídeos/fisiologia , Masculino , Mitocôndrias/metabolismo , Morfolinas/farmacologia , Naftalenos/farmacologia , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Estresse Oxidativo/fisiologia , Alcamidas Poli-Insaturadas/farmacologia , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Receptores de Canabinoides/metabolismo , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/fisiologiaRESUMO
Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a transcription factor involved in the orchestration of antioxidant responses. Although its pharmacological activation has been largely hypothesized as a promising tool to ameliorate the progression of neurodegenerative events, the actual knowledge about its modulation in neurotoxic paradigms remains scarce. In this study, we investigated the early profile of Nrf2 modulation in striatal slices of rodents incubated in the presence of the toxic kynurenine pathway metabolite, quinolinic acid (QUIN). Tissue slices from rats and mice were obtained and used throughout the experiments in order to compare inter-species responses. Nuclear Nrf2 protein levels and oxidative damage to lipids were compared. Time- and concentration-response curves of all markers were explored. Nrf2 nuclear activation was corroborated through phase 2 antioxidant protein expression. The effects of QUIN on Nrf2 modulation and oxidative stress were also compared between slices of wild-type (Nrf2(+/+)) and Nrf2 knock-out (Nrf2(-/-)) mice. The possible involvement of the N-methyl-d-aspartate receptor (NMDAr) in the Nrf2 modulation and lipid peroxidation was further explored in mice striatal slices. In rat striatal slices, QUIN stimulated the Nrf2 nuclear translocation. This effect was accompanied by augmented lipid peroxidation. In the mouse striatum, QUIN per se exerted an induction of Nrf2 factor only at 1h of incubation, and a concentration-response effect on lipid peroxidation after 3h of incubation. QUIN stimulated the striatal content of phase 2 enzymes. Nrf2(-/-) mice were slightly more responsive than Nrf2(+/+) mice to the QUIN-induced oxidative damage, and completely unresponsive to the NMDAr antagonist MK-801 when tested against QUIN. Findings of this study indicate that: (1) Nrf2 is modulated in rodent striatal tissue in response to QUIN; (2) Nrf2(-/-) striatal tissue was moderately more vulnerable to oxidative damage than the Wt condition; and (3) early Nrf2 up-regulation reflects a compensatory response to the QUIN-induced oxidative stress in course as part of a general defense system, whereas Nrf2 down-regulation might contribute to more intense oxidative cell damage.
Assuntos
Corpo Estriado/efeitos dos fármacos , Corpo Estriado/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo/fisiologia , Ácido Quinolínico/toxicidade , Animais , Feminino , Humanos , Cinurenina/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ratos , Ratos WistarRESUMO
Quinolinic acid (QA)-induced overactivation of N-methyl-d-aspartate receptors yields excitotoxicity, oxidative stress and mitochondrial dysfunction, which altogether contribute to trigger a wide variety of toxic pathways with biochemical, behavioral and neuropathological alterations similar to those observed in Huntington's disease. Noteworthy, in the brains of these patients, increased expression of heme oxygenase-1 (HO-1) levels can be found. It has been proposed that this enzyme can exert a dual role, as it can be either protective or deleterious to the CNS. While some evidence indicates that its overexpression affords cellular anti-oxidant protection due to decreased concentrations of its pro-oxidative substrate heme group, and increased bilirubin levels, other reports established that high HO-1 expression and activity may result in a pro-oxidizing atmosphere due to a release of Fe(2+). In this work, we examined the temporal evolution of oxidative damage to proteins, HO-1 expression, immunoreactivity, total activity, and cell death after 1, 3, 5 and 7 days of an intrastriatal QA infusion (240 nmol/µl). QA was found to induce cellular degeneration, increasing carbonylated proteins and generating a transitory response in HO-1 mRNA, protein content, and immunoreactivity and activity in nerve cells. In order to study the role of HO-1 in the QA-induced cellular death, the tin protoporphyrin IX (SnPP), a well-known HO inhibitor, was administered to rats (30 µmol/kg, i.p.). The administration of SnPP to animals treated with QA inhibited the HO activation, and exacerbated the striatal cell damage induced by QA. Our findings reveal a potential modulatory role of HO-1 in the toxic paradigm evoked by QA in rats. This evidence provides a valuable tool for further approaches on HO-1 regulation in neurotoxic paradigms.
Assuntos
Corpo Estriado/metabolismo , Heme Oxigenase-1/antagonistas & inibidores , Degeneração Neural/metabolismo , Estresse Oxidativo/fisiologia , Regulação para Cima/fisiologia , Animais , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/patologia , Heme Oxigenase-1/metabolismo , Masculino , Metaloporfirinas/farmacologia , Degeneração Neural/induzido quimicamente , Degeneração Neural/patologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Fármacos Neuroprotetores/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Protoporfirinas/farmacologia , Ácido Quinolínico , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Regulação para Cima/efeitos dos fármacosRESUMO
Introducción: Los catéteres venosos centrales (CVC) plantean un alto riesgo de infección. La infección del sitio de salida (ISS-CVC) es la menos estudiada, y se desconoce su asociación con la bacteriemia asociada a catéter (BAC) y su impacto en la evolución del paciente. Objetivo: Evaluar la asociación entre ISS-CVC, BAC y mortalidad. Materiales y métodos: Estudio prospectivo, de observación. Pacientes internados en una Unidad de Terapia Intensiva médico/quirúrgica que requirieron la colocación de CVC desde el 01/06/2010 hasta el 01/04/2012. Se evaluaron datos epidemiológicos, BAC (según criterios de los CDC) y gérmenes. Se utilizaron media ± DE, mediana y rango intercuartílico, y porcentajes. Resultados: Durante este período, ingresaron 575 pacientes, el 98% requirió CVC. Datos de los pacientes: edad 41 ± 26 años, APACHE II 15 ± 7, 96% con ventilación mecánica, días de ventilación mecánica 41 (33-63), días de internación 43 (25-67). Todos los CVC con ISS fueron retirados y cultivados. Se observaron 51 ISS: 5,5/1000-días-catéter: 33% subclavia, 38% yugular, 29% femoral. Seis pacientes con ISS (12%) tuvieron BAC (0,65/1000-días-catéter): 3 subclavias, 2 yugulares, 1 femoral; 2 con halo y 8 con secreción purulenta. Tiempo de permanencia del CVC: 7,5 días (5-10). Clínica al momento de la ISS: shock 50%, fiebre 83%, SOFA 6 ± 3. El 83% de las infecciones fueron monomicrobianas: 83% por bacilos gramnegativos (2 Klebsiella, 2 Pseudomonas, 1 Serratia y 1 Acinetobacter), 17% por enterococos resistentes a vancomicina. La mortalidad fue del 50%. Conclusión: Aunque la ISS provocó una baja incidencia de BAC, la mortalidad fue alta. Al parecer, la ISS no es un factor predictivo de BAC.(AU)
Introduction: Central venous catheters (CVC) are widely used and pose a high risk of infection. There are few studies on insertion site infection (ISI-CVC), and both its association with catheter-associated bloodstream infection (CABSI) and the outcome of patients are unknown. Objective: To determine the association between ISI-CVC, the presence of CABSI and mortality. Materials and methods: Prospective observational study. All patients admitted to a medical/surgical Intensive Care Unit requiring CVC insertion from 06/01/2010 to 04/01/2012 were included. Epidemiological data, CABSI (according to CDC criteria) and microorganisms involved were evaluated. Mean ± SD, median and interquartile range, and percentages were used. Results: During the period study, 575 patients were admitted, 98% required CVC. Patient´s data: age 41 ± 26 years, APACHE II 15 ± 7, 96% on mechanical ventilation, days on mechanical ventilation: 41 (33-63), length of stay 43 (25-67) days. All CVCs with ISI were removed and cultured. Fifty one ISI were observed (5.5/1000-catheter-day). Six patients with ISI (12%) presented CABSI (0.65/1000-catheter-day): 3 in subclavian, 2 in jugular, 1 femoral; 2 with erythema and 8 with purulent secretion. CVC permanence: 7.5 day (5-10). Signs and/or symptoms at the moment of ISI: shock 50%, fever 83%, SOFA 6 ± 3. The 83% of infections were caused by one microorganism: 83% due to gram-negative bacilli (2 Klebsiella, 2 Pseudomonas, 1 Serratia, and 1 Acinetobacter), 17% due to vancomycin-resistant enterococci. The mortality rate was 50%. Conclusion: Although ISI-CVC presented a low incidence of CABSI, mortality rate was high. The ISI-CVC might have a little predictable value for CABSI.(AU)
Assuntos
Humanos , Bacteriemia/mortalidade , Cateteres Venosos Centrais , Infecções , MortalidadeRESUMO
INTRODUCTION: Poor perinatal outcome in patients with preeclampsia has been reported. This significant risk reinforces the importance of fetal evaluation. OBJECTIVE: The purpose of this study was to evaluate the utility of the nonstress test (NST) in preeclampsia. STUDY DESIGN: Criteria for inclusion in this report comprised pregnancies complicated by preeclampsia of longer than 28 weeks of gestation delivered 24 hours of final NST. The study population were divided into mild and severe preeclampsia. Each of the latter two groups was further subdivided into three subgroups by gestational age at 28-31, 32-34 and > 35 weeks. Measurements of adverse perinatal outcome included meconium staining, oligohydramnios, five-minute Apgar score less than 7 beyond 34 weeks of gestational age, intrauterine growth retardation, and perinatal death. RESULTS: A total of 250 patients with preeclampsia were analyzed, among these 147 with mild and 103 with severe disease. There were no stillbirths. Sensitivity of the NST was low ranged from 39% (mild preeclampsia) to 63% (severe disease). Its positive predictive value was equally low (66 and 45%) respectively. Specificity was quite high in both groups (89 and 64%). Its negative predictive value was 73% for mild disease and 78% for severe preeclampsia. CONCLUSION: The NST is an important test in antepartum care but based on its low sensitivity should not be considered as a stand alone test.
Assuntos
Pré-Eclâmpsia/diagnóstico , Feminino , Humanos , Gravidez , Estudos Prospectivos , Sensibilidade e Especificidade , Índice de Gravidade de DoençaRESUMO
OBJECTIVE: To describe the maternal morbidity and mortality in pregnancies complicated by HELLP Syndrome. STUDY DESIGN: This is a descriptive and prospective study of women with HELLP Syndrome managed at our center from January 1998 through March 2000. Patients are grouped into 3-class system of Mississippi classification. RESULTS: 170 cases were analysed, 156 (92%), ocurred ante partum and 14 (8%) postpartum; 15 cases (9%) developed at < 27 weeks, 112 (66%) between 28 to 36 weeks of gestational age and 43 (25%) at term. Maternal morbidity included acute renal failure (13.5%), abruptio placentae (6.6%), pneumonia (3%), subcapsular liver hematoma (2.3%), pulmonary edema (2.3%), diseminated intravascular coagulopathy (1.7%) and cerebral hemorrhage (1.2%). Maternal mortality was 4.7% (8 patients), 7 deaths ocurred in patients with class I disease and only one with class II HELLP Syndrome. 6 maternal deaths (75%) were associated to eclampsia. Up to 85% of the maternal morbidity and mortality developed with class I disease (platelet nadir < 50,000 mm3. CONCLUSIONS: There is a progressive rise in maternal morbidity and mortality as the pregnancy moves from class III to class I HELLP Syndrome. 75% of maternal mortality was associated with eclampsia. Early diagnosis of this syndrome could improve maternal prognosis and outcome.