ABSTRACT
OBJETIVO: Determinar se um protocolo curto de sensibilização com ovalbumina subcutânea, sem adjuvante, induziria uma resposta pulmonar eosinofílica em pulmões de camundongos similar àquela encontrada em protocolos previamente estabelecidos. MÉTODOS: Fêmeas adultas de camundongos BALB/c foram randomizadas e divididas em grupos de acordo com o número de sensibilizações com ovalbumina e o número/dosagem de provocação intranasal. O protocolo curto (10 dias) consistiu de uma sensibilização e três provocações com ovalbumina (100 µg). A contagem total e diferencial de células no lavado broncoalveolar, o nível de peroxidase eosinofílica no tecido pulmonar e o exame histopatológico dos pulmões foram realizados 24 h após a última provocação. RESULTADOS: Não houve diferenças significativas entre os grupos em relação às variáveis estudadas. O protocolo curto, assim como os outros protocolos estudados, induziu uma resposta eosinofílica pulmonar semelhante àquela do grupo controle positivo. CONCLUSÕES: A sensibilização por ovalbumina subcutânea sem o uso de adjuvante resultou em uma significativa resposta pulmonar alérgica em ratos, mesmo no grupo de protocolo curto. Nossos achados sugerem que esse protocolo curto pode ser utilizado como teste pré-clínico de primeira linha para a pesquisa de novos fármacos, reduzindo custos e o tempo de observação.
OBJECTIVE: To determine whether a short-term protocol using subcutaneous sensitization with ovalbumin, without the use of adjuvants, would induce an eosinophilic response in the lungs of mice similar to that observed in previous, well-established protocols. METHODS: Adult female BALB/c mice were randomized and divided into groups according to the number of sensitizations with ovalbumin and the number/dosage of intranasal ovalbumin challenges. The short-term protocol (10 days) consisted of one sensitization with ovalbumin and three ovalbumin challenges (100 µg). Total and differential cell counts in BAL fluid, levels of eosinophil peroxidase in lung tissue, and histopathological examination of the lungs were performed 24 h after the last ovalbumin challenge. RESULTS: No significant differences were found among the groups regarding the variables studied. The short-term protocol, as well as the other protocols studied, induced an eosinophilic response similar to that obtained in the positive control. CONCLUSIONS: Subcutaneous sensitization with ovalbumin and without the use of adjuvants resulted in a significant allergic response in the lungs of mice, even in the short-term protocol group. Our findings suggest that this short-term protocol can be used as a first-line pre-clinical test for the study of new medications, reducing the costs and observation periods.
Subject(s)
Animals , Female , Mice , Asthma/pathology , Bronchial Hyperreactivity/pathology , Eosinophil Peroxidase/metabolism , Lung/pathology , Ovalbumin , Pulmonary Eosinophilia/immunology , Acute Disease , Asthma/enzymology , Bronchial Provocation Tests , Bronchial Hyperreactivity/enzymology , Bronchoalveolar Lavage Fluid/cytology , Disease Models, Animal , Lung/enzymology , Mice, Inbred BALB C , Pulmonary Eosinophilia/pathology , Random AllocationABSTRACT
Current therapeutic approaches for the treatment of asthma have limitations in their ability to target all the features of the disease. Indeed, existing pharmacological asthma therapies are based on decades old strategies that were developed prior to the rapid growth in knowledge stemming from cell and molecular biology in the past decade. Thus, there is an unmet need for developing new drugs to target these features along with improved efficacy and safety. In the present review, the limitations of prevalent pharmacological asthma therapy are discussed briefly, and some explanations are suggested as to why new therapeutic targets are required to treat asthma, and finally directions for novel asthma therapies are proposed.
Subject(s)
Animals , Asthma/drug therapy , Asthma/enzymology , Asthma/genetics , Asthma/metabolism , Bronchodilator Agents/metabolism , Bronchodilator Agents/pharmacology , Bronchodilator Agents/therapeutic use , Cytokines/metabolism , Enzyme Inhibitors/metabolism , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/therapeutic use , Humans , Oligonucleotides/metabolism , Oligonucleotides/therapeutic use , Transcription Factors/antagonists & inhibitorsABSTRACT
PURPOSE: A possible involvement of autoimmune mechanism in the pathogenesis of bronchial asthma has been proposed. Recently, alpha-enolase protein was identified as a major autoantigen recognized by circulating IgG autoantibodies in patients with severe asthma. To evaluate a possible pathogenetic significance of these autoantibodies in severe asthma, isotype (IgG, IgA, IgM, and IgE) and IgG subclass (IgG1, IgG2, IgG3, and IgG4) distributions of autoantibodies to recombinant human alpha-enolase protein were analyzed. PATIENTS AND METHODS: We examined serum samples from 10 patients with severe asthma and 7 patients with mild-to-moderate asthma, and 5 healthy controls by immunoblot analysis. Severe asthma was defined as patients having at least 1 severe asthmatic exacerbation requiring an emergency department visit or admission in the last year despite continuous typical therapies. RESULTS: IgG1 was the predominant IgG subclass antibody response to alpha-enolase protein in patients with severe asthma. IgG1 autoantibody to alpha-enolase protein was detected in 7 of 10 patients with severe asthma (70%), 1 of 7 patients with mild-to-moderate asthma (14.3%), and none of 5 healthy controls (0%) (chi-square test; p < 0.05). IgA, IgM, and IgE autoantibodies to alpha-enolase protein could not be detected in patients with severe asthma. CONCLUSION: IgG1 subclass was the predominant type of autoantibody response to alpha-enolase protein in patients with severe asthma, suggests a possibility of IgG1 autoantibody- mediated complement activation in the pathogenesis of severe asthma.
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Young Adult , Asthma/enzymology , Autoantibodies/blood , Autoantigens , Case-Control Studies , Complement Activation , Immunoglobulin G/blood , Immunoglobulin Isotypes/blood , Phosphopyruvate Hydratase/immunology , Recombinant Proteins/immunologyABSTRACT
Asthma is one of the most common chronic inflammatory disorder of the airways of the lungs, affecting more than 300 million people all over the world. Nitric oxide (NO) is endogenously produced in mammalian airways by nitric oxide synthase (NOS) and is known to regulate many aspects of human asthma, including the modulation of airway and vascular smooth muscle tone and the inflammation. Asthmatic patients show an increased expression of inducible nitric oxide synthase (iNOS) in airway epithelial cells and an increased level of NO in exhaled air. Using various NO inhibitors (non-specific or iNOS-specific) and gene knock-out experiments, controversial results have been obtained regarding iNOS's beneficial and deleterious effects in the disease. In the present review, we have attempted to summarize the results of these experiments and also the genetic studies being undertaken to understand the role of iNOS in asthma. It is argued that extensive biochemical, clinical and genetic studies will be required to assess the precise role of NO in the asthma. This may help in designing selective and more potent iNOS inhibitors and NO donors for developing novel therapeutics for the asthma patients.
Subject(s)
Animals , Asthma/enzymology , Humans , Lung/enzymology , Models, Biological , Nitric Oxide/metabolism , Nitric Oxide Synthase Type II/metabolismABSTRACT
Asthma results from allergen-driven intrapulmonary Th2 response, and is characterized by intermittent airway obstruction, airway hyperreactivity (AHR), and airway inflammation. Accumulating evidence indicates that inflammatory diseases of the respiratory tract are commonly associated with elevated production of nitric oxide (NO). It has been shown that exhaled NO may be derived from constitutive NO synthase (NOS) such as endothelial (NOS 3) and neural (NOS 1) in normal airways, while increased levels of NO in asthma appear to be derived from inducible NOS2 expressed in the inflamed airways. Nevertheless, the functional role of NO and NOS isoforms in the regulation of AHR and airway inflammation in human or experimental models of asthma is still highly controversial. In the present commentary we will discuss the role of lipopolysaccharides contamination of allergens as key element in the controversy related to the regulation of NOS2 activity in experimental asthma.
Subject(s)
Animals , Humans , Allergens/immunology , Asthma/enzymology , Lipopolysaccharides/immunology , Nitric Oxide Synthase Type II/metabolism , Nitric Oxide/biosynthesis , Asthma/immunology , Disease Models, Animal , Enzyme ActivationABSTRACT
To explore the expression of heme oxygenase-1 (HO-1) in the peripheral blood mononuclear cells (PBMCs) and its relationship with pulmonary ventilation function in asthmatic patients, 18 asthmatic patients and 18 healthy subjects were selected. HO-1 protein and mRNA levels in PBMCs were measured by immunohistochemical staining and reverse transcription-polymerase chain reaction (RT-PCR), respectively. Blood carbon monoxide Hb (COHb), serum total IgE and pulmonary ventilatory function were observed. Our results showed that the percentage of cells positive for immunohistochemical staining of HO-1 were significantly higher in asthmatic patients (41.72 +/- 7.44) % than that in with healthy subjects (10.45 +/- 4.36) % (P < 0.001) and the optical density of PBMC HO-1 mRNA was higher in asthmatic patients (26.05 +/- 4.14) than that in healthy subjects (10. 82 +/- 4.26) (P < 0.001). The relation analysis showed that PBMC HO-1 protein and mRNA levels had significantly negative relation with FEV1%, PEFR, MEFR50%, respectively (r = -0.51-0.89, P < 0.05-0.001, respectively) and a positive relation with COHb and serum total IgE (r = 0.48-0. 85, 0.05-0.001, respectively). It is concluded that the expression of PBMC HO-1 protein and mRNA increased significantly in asthmatic patients, and HO-1 may play a significant role in the pathogenesis of asthma. The expression of HO-1 may bear a relation with severity of asthma.
Subject(s)
Asthma/blood , Asthma/enzymology , Carbon Monoxide/blood , Heme Oxygenase-1/biosynthesis , Heme Oxygenase-1/blood , Immunoglobulin E/blood , Leukocytes, Mononuclear/enzymology , RNA, Messenger/bloodABSTRACT
Asthma is an inflammatory condition characterized by the involvement of several mediators, including reactive oxygen species. The aim of the present study was to investigate the superoxide release and cellular glutathione peroxidase (cGPx) activity in peripheral blood granulocytes and monocytes from children and adolescents with atopic asthma. Forty-four patients were selected and classified as having intermittent or persistent asthma (mild, moderate or severe). The spontaneous or phorbol myristate acetate (PMA, 30 nM)-induced superoxide release by granulocytes and monocytes was determined at 0, 5, 15, and 25 min. cGPx activity was assayed spectrophotometrically. The spontaneous superoxide release by granulocytes from patients with mild (N = 15), moderate (N = 12) or severe (N = 6) asthma was higher at 25 min compared to healthy individuals (N = 28, P < 0.05, Duncan test). The PMA-induced superoxide release by granulocytes from patients with moderate (N = 12) or severe (N = 6) asthma was higher at 15 and 25 min compared to healthy individuals (N = 28, P < 0.05 in both times of incubation, Duncan test). The spontaneous or PMA-induced superoxide release by monocytes from asthmatic patients was similar to healthy individuals (P > 0.05 in all times of incubation, Duncan test). cGPx activity of granulocytes and monocytes from patients with persistent asthma (N = 20) was also similar to healthy individuals (N = 10, P > 0.05, Kruskal-Wallis test). We conclude that, under specific circumstances, granulocytes from children with persistent asthma present a higher respiratory burst activity compared to healthy individuals. These findings indicate a risk of oxidative stress, phagocyte auto-oxidation, and the subsequent release of intracellular toxic oxidants and enzymes, leading to additional inflammation and lung damage in asthmatic children.
Subject(s)
Humans , Male , Female , Child , Adolescent , Asthma/blood , Glutathione Peroxidase/metabolism , Granulocytes/enzymology , Monocytes/enzymology , Superoxide Dismutase/biosynthesis , Asthma/enzymology , Biomarkers/blood , Case-Control Studies , Chronic Disease , Time FactorsABSTRACT
Se describen los niveles de IgE sérica en una muestra de 69 niños con diagnóstico de asma bronquial, de la meseta central de Costa Rica, así como de 33 niños aparentemente sanos, sin historia clínica de alergias, y de 20 adultos donadores de sangre. La comparación mostró un mayor promedio de IgE sérica en el grupo de niños asmáticos con respecto al grupo control, así como una mayor frecuencia de niveles de IgE muy aumentados (>1000 kU/l) en los niños asmáticos. Los valores de IgE hallados en los niños aparentemente sanos son más similares a los descritos en poblaciones de países tropicales que de países de Europa y Norteamérica. Se realizó una comparación entre un método inmunoenzimático y uno radioinmune para la cuantificación de IgE y se obtuvo un coeficiente de correlación de 0,947