RESUMO
Extracellular superoxide dismutase (EC-SOD) is abundant in the lung and limits inflammation and injury in response to many pulmonary insults. To test the hypothesis that EC-SOD has an important role in bacterial infections, wild-type and EC-SOD knockout (KO) mice were infected with Escherichia coli to induce pneumonia. Although mice in the EC-SOD KO group demonstrated greater pulmonary inflammation than did wild-type mice, there was less clearance of bacteria from their lungs after infection. Macrophages and neutrophils express EC-SOD; however, its function and subcellular localization in these inflammatory cells is unclear. In the present study, immunogold electron microscopy revealed EC-SOD in membrane-bound vesicles of phagocytes. These findings suggest that inflammatory cell EC-SOD may have a role in antibacterial defense. To test this hypothesis, phagocytes from wild-type and EC-SOD KO mice were evaluated. Although macrophages lacking EC-SOD produced more reactive oxygen species than did cells expressing EC-SOD after stimulation, they demonstrated significantly impaired phagocytosis and killing of bacteria. Overall, this suggests that EC-SOD facilitates clearance of bacteria and limits inflammation in response to infection by promoting bacterial phagocytosis.
Assuntos
Escherichia coli/citologia , Espaço Extracelular/enzimologia , Macrófagos/citologia , Macrófagos/enzimologia , Viabilidade Microbiana , Fagocitose , Superóxido Dismutase/metabolismo , Animais , Humanos , Inflamação/microbiologia , Inflamação/patologia , Espaço Intracelular/metabolismo , Pulmão/microbiologia , Pulmão/patologia , Macrófagos/ultraestrutura , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Oxidantes/metabolismo , Pneumonia/microbiologia , Pneumonia/patologia , Superóxido Dismutase/ultraestruturaRESUMO
Lung disease due to Mycobacterium avium complex (MAC) organisms is increasing. A greater understanding of the host immune response to MAC organisms will provide a foundation to develop novel therapies for these recalcitrant infections. IL-32 is a newly described pro-inflammatory cytokine that enhances host immunity against various microbial pathogens. Cytokines that induce IL-32 such as interferon-gamma, IL-18, IL-12 and tumor necrosis factor-alpha are of considerable importance to mycobacterial immunity. We performed immunohistochemistry and morphometric analysis to quantify IL-32 expression in the lungs of 11 patients with MAC lung disease and 10 controls with normal lung tissues. After normalizing for basement membrane length, there was a profound increase in IL-32 expression in the airway epithelial cells of the MAC-infected lungs compared with controls. Following normalization for alveolar surface area, there was a trend toward increased IL-32 expression in type II alveolar cells and alveolar macrophages in the lungs of MAC patients. Human airway epithelial cells (BEAS-2B) infected with M. avium produced IL-32 by a nuclear factor-kappa B-dependent mechanism. In both BEAS-2B cells and human monocyte-derived macrophages, exogenous IL-32γ significantly reduced the growth of intracellular M. avium. This finding was corroborated by an increase in the number of intracellular M. avium recovered from THP-1 monocytes silenced for endogenous IL-32 expression. The anti-mycobacterial effect of IL-32 may be due, in part, to increased apoptosis of infected cells. These findings indicate that IL-32 facilitates host defense against MAC organisms but may also contribute to the airway inflammation associated with MAC pulmonary disease.
Assuntos
Células Epiteliais/imunologia , Interleucinas/imunologia , Macrófagos Alveolares/imunologia , Macrófagos/imunologia , Monócitos/imunologia , Complexo Mycobacterium avium/imunologia , Infecção por Mycobacterium avium-intracellulare/imunologia , Sistema Respiratório/imunologia , Idoso , Estudos de Casos e Controles , Células Cultivadas , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/microbiologia , Feminino , Expressão Gênica , Humanos , Imuno-Histoquímica , Interferon gama/imunologia , Interleucina-12/imunologia , Interleucina-18/imunologia , Interleucinas/genética , Interleucinas/farmacologia , Macrófagos/efeitos dos fármacos , Macrófagos/microbiologia , Macrófagos Alveolares/efeitos dos fármacos , Macrófagos Alveolares/microbiologia , Pessoa de Meia-Idade , Monócitos/efeitos dos fármacos , Monócitos/microbiologia , Complexo Mycobacterium avium/efeitos dos fármacos , Complexo Mycobacterium avium/crescimento & desenvolvimento , Infecção por Mycobacterium avium-intracellulare/tratamento farmacológico , Infecção por Mycobacterium avium-intracellulare/metabolismo , Infecção por Mycobacterium avium-intracellulare/microbiologia , NF-kappa B/imunologia , Sistema Respiratório/efeitos dos fármacos , Sistema Respiratório/metabolismo , Sistema Respiratório/microbiologia , Fator de Necrose Tumoral alfa/imunologia , Estados UnidosRESUMO
Pulmonary immunity depends on the ability of leukocytes to neutralize potentially harmful and frequent insults to the lung, and appropriate regulation of leukocyte migration and adhesion is integral to this process. Arhgef1 is a hematopoietic-restricted signaling molecule that regulates leukocyte migration and integrin-mediated adhesion. To explore a possible regulatory role for Arhgef1 in pulmonary immunity we examined the lung and its leukocytes in wild-type and Arhgef1-deficient animals. Here we report that the lungs of Arhgef1-/- mice harbored significantly more leukocytes, increased expression and activity of matrix metalloproteinases (MMPs), airspace enlargement, and decreased lung elastance compared with wild-type lungs. Transfer of Arhgef1-/- lung leukocytes to wild-type mice led to airspace enlargement and impaired lung function, indicating that loss of Arhgef1 in leukocytes was sufficient to induce pulmonary pathology. Furthermore, we showed that Arhgef1-deficient peritoneal macrophages when either injected into the lungs of wild-type mice or cultured on fibronectin significantly increased expression and activity of MMPs relative to control macrophages, and the in vitro fibronectin induction was dependent on the alpha5beta1 integrin pair. Together these data demonstrate that Arhgef1 regulates alpha5beta1-mediated MMP expression by macrophages and that loss of Arhgef1 by leukocytes leads to pulmonary pathology.
Assuntos
Fatores de Troca do Nucleotídeo Guanina/metabolismo , Homeostase/imunologia , Imunidade/imunologia , Integrina alfa5beta1/metabolismo , Pulmão/enzimologia , Pulmão/imunologia , Metaloproteinases da Matriz/genética , Proteínas Proto-Oncogênicas/metabolismo , Animais , Fenômenos Biomecânicos/efeitos dos fármacos , Líquido da Lavagem Broncoalveolar/citologia , Células Cultivadas , Fibronectinas/farmacologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Fatores de Troca do Nucleotídeo Guanina/deficiência , Homeostase/efeitos dos fármacos , Imunidade/efeitos dos fármacos , Contagem de Leucócitos , Leucócitos/efeitos dos fármacos , Leucócitos/enzimologia , Leucócitos/patologia , Ligantes , Pulmão/patologia , Pulmão/fisiopatologia , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/enzimologia , Macrófagos Peritoneais/patologia , Metaloproteinases da Matriz/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Proto-Oncogênicas/deficiência , Testes de Função Respiratória , Fatores de Troca de Nucleotídeo Guanina Rho , Transdução de Sinais/efeitos dos fármacosRESUMO
Recent studies in animal models of bronchopulmonary dysplasia (BPD) suggest that antioxidant treatments may be beneficial for the disease. However, the mechanisms by which these drugs improve the course of BPD are not completely known. Alpha1-antitrypsin (α1-AT) is one of the major serine protease inhibitors in human plasma that has antielastase and antiapoptotic activities. Both activities of α1-AT are dependent on its reactive site loop (RSL), which is highly susceptible to oxidative inactivation. In this study, we investigated the elastase inhibitory activity of α1-AT in two different baboon models of BPD, the "new BPD" and the "severe BPD" models, and determined the effect of treatment with a catalytic antioxidant, Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP), on the elastase inhibitory activity of α1-AT in the severe BPD model. Our results demonstrate the presence of sufficient elastase inhibitory activity of the airway α1-AT in the new but not in the severe BPD model. Treatment of severe BPD group baboons with the catalytic antioxidant MnTE-2-PyP resulted in augmentation of the elastase inhibitory activity of α1-AT. These findings suggest that prevention of the oxidative inactivation of α1-AT may be one of the mechanisms by which antioxidant therapy improves the pulmonary outcomes in animal models of severe BPD.
Assuntos
Antioxidantes/uso terapêutico , Displasia Broncopulmonar/tratamento farmacológico , Elastase de Leucócito/antagonistas & inibidores , Metaloporfirinas/uso terapêutico , alfa 1-Antitripsina/metabolismo , Animais , Líquido da Lavagem Broncoalveolar/química , Líquido da Lavagem Broncoalveolar/citologia , Catálise , Modelos Animais de Doenças , Idade Gestacional , Humanos , Recém-Nascido , Fígado/metabolismo , Pulmão/metabolismo , PapioRESUMO
RATIONALE: Nitric oxide (NO) plays an important role in lung development and perinatal lung function, and pulmonary NO synthases (NOS) are decreased in bronchopulmonary dysplasia (BPD) following preterm birth. Fetal estradiol levels increase during late gestation and estradiol up-regulates NOS, suggesting that after preterm birth estradiol deprivation causes attenuated lung NOS resulting in impaired pulmonary function. OBJECTIVE: To test the effects of postnatal estradiol administration in a primate model of BPD over 14 days after delivery at 125 days of gestation (term = 185 d). METHODS: Cardiopulmonary function was assessed by echocardiography and whole body plethysmography. Lung morphometric and histopathologic analyses were performed, and NOS enzymatic activity and abundance were measured. MEASUREMENTS AND MAIN RESULTS: Estradiol caused an increase in blood pressure and ductus arteriosus closure. Expiratory resistance and lung compliance were also improved, and this occurred before spontaneous ductal closure. Furthermore, both oxygenation and ventilation indices were improved with estradiol, and the changes in lung function and ventilatory support requirements persisted throughout the study period. Whereas estradiol had negligible effect on indicators of lung inflammation and on lung structure assessed after the initial 14 days of ventilatory support, it caused an increase in lung neuronal and endothelial NOS enzymatic activity. CONCLUSIONS: In a primate model of BPD, postnatal estradiol treatment had favorable cardiovascular impact, enhanced pulmonary function, and lowered requirements for ventilatory support in association with an up-regulation of lung NOS. Estradiol may be an efficacious postnatal therapy to improve lung function and outcome in preterm infants.
Assuntos
Displasia Broncopulmonar/terapia , Estradiol/farmacologia , Estrogênios/farmacologia , Óxido Nítrico Sintase/metabolismo , Regulação para Cima , Animais , Animais Recém-Nascidos , Pressão Sanguínea/efeitos dos fármacos , Líquido da Lavagem Broncoalveolar/química , Modelos Animais de Doenças , Canal Arterial/efeitos dos fármacos , Elastina/genética , Elastina/metabolismo , Estradiol/sangue , Feminino , Humanos , Recém-Nascido , Pulmão/metabolismo , Pulmão/patologia , Complacência Pulmonar , Masculino , Oxigênio/sangue , Papio , Surfactantes Pulmonares/metabolismo , RNA Mensageiro/metabolismo , Distribuição Aleatória , Receptores de Estradiol/metabolismo , Respiração ArtificialRESUMO
Oxidative damage is a major cause of lung injury during systemic inflammatory response syndrome. In this study, the expression of an antioxidant enzyme, extracellular superoxide dismutase (EC-SOD), and its protective role against pulmonary oxidative damage were investigated using mouse models of systemic inflammation. Intraperitoneal injection with bacterial endotoxin lipopolysaccharides (LPS; 20 mg/kg) caused oxidative damage in lungs as assessed by increased tyrosine nitration in proteins. LPS administration also resulted in a rapid and significant loss of more than 80% of pulmonary EC-SOD in a time- and dose-dependent manner, but other types of SODs, cytoplasmic CuZn-SOD and mitochondrial Mn-SOD, were not affected. EC-SOD protein is most abundant in lungs but also present at high levels in other tissues such as heart and white fat; however, the LPS-mediated decrease in this enzyme was most apparent in the lungs. Intravenous injection of mice with tumor necrosis factor alpha (10 microg per mouse) also caused a 60% decrease in EC-SOD in the lungs, suggesting that the EC-SOD down-regulation is mediated by this LPS-inducible inflammatory cytokine. A protective role for EC-SOD against LPS-mediated systemic inflammation was shown by an increased survival rate (75% vs 29% in 5 days) and decreased pulmonary oxidative damage in EC-SOD transgenic mice that overexpress the human EC-SOD gene. These results demonstrate that the inflammation-mediated EC-SOD down-regulation has a major pathophysiological impact during the systemic inflammatory response syndrome.
Assuntos
Espaço Extracelular/enzimologia , Inflamação/metabolismo , Pulmão/enzimologia , Superóxido Dismutase/metabolismo , Animais , Sequência de Bases , Northern Blotting , Primers do DNA , Relação Dose-Resposta a Droga , Regulação para Baixo , Inflamação/induzido quimicamente , Lipopolissacarídeos/toxicidade , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Superóxido Dismutase/genética , Transcrição GênicaRESUMO
Bronchopulmonary dysplasia (BPD), a chronic lung disease affecting preterm neonates, is associated with significant childhood and adult health problems. Histopathologic features of BPD include impaired vascular and distal airway development. We previously showed that activation of hypoxia-inducible factors (HIFs) by inhibition of prolyl hydroxylase domain-containing proteins (PHDs) is feasible and that it stimulates vascular endothelial growth factor (VEGF)-dependent angiogenesis in vitro. We tested the hypothesis that enhancement of angiogenesis by activation of HIFs improves lung growth and function in prematurely born neonates in vivo. Preterm baboons (125 day+14 day pro re nata O2 model, corresponding to 27 human gestational weeks) were treated for 14 days with intravenous (i.v.) FG-4095, a PHD inhibitor. Notably, 77% of diminished total alveolar surface area in untreated controls was recovered by FG-4095 treatment. Functional significance of the structural changes was indicated by improved oxygenation and lung compliance in FG-4095-treated newborns. Surfactant proteins B and C and saturated phosphatidylcholine were unchanged. Incidence of spontaneous ductus arteriosus closure was increased, likely contributing to lower ratio of pulmonary to systemic blood flow in FG-4095 group. These findings indicate that HIF stimulation by PHD inhibition ameliorates pathological and physiological consequences of BPD.
Assuntos
Fator 1 Induzível por Hipóxia/metabolismo , Pneumopatias/tratamento farmacológico , Pulmão/crescimento & desenvolvimento , Nascimento Prematuro , Animais , Animais Recém-Nascidos , Doença Crônica , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/farmacologia , Feminino , Fator 1 Induzível por Hipóxia/fisiologia , Pulmão/patologia , Pulmão/fisiopatologia , Pneumopatias/etiologia , Masculino , Neovascularização Fisiológica/efeitos dos fármacos , Papio , Testes de Função Respiratória , Resultado do TratamentoRESUMO
High oxygen concentrations (hyperoxia), often required in the treatment of preterm infants and critically ill patients, cause lung injury, targeting especially the endothelium. Exposure of primary human lung microvascular endothelial cells (HLMVEC) to hyperoxia caused transient Akt activation after 60 min, as determined by Western blot analysis of phosphorylated Ser 473 of Akt. Akt phosphorylation was also increased after 24 h of hyperoxic exposure, which declined at 48 h. Adenoviral (Ad)-mediated expression of constitutively active myrAkt protected HLMVEC against hyperoxic injury. Cell death due to hyperoxia (95% O2, 8 days), which was primarily necrotic, was substantial in control and Ad-LacZ-transduced cells, but was diminished by almost half in myrAkt-transduced cells. Hyperoxia caused increased cellular glucose consumption, an effect that was amplified in cells transduced with myrAkt compared to the LacZ-transduced or the nontransduced controls. Increased glucose consumption in myrAkt-expressing cells was accompanied by increased phosphorylation of mTOR and p70 S6-kinase. Rapamycin treatment decreased glucose consumption in myrAkt-transduced cells to levels comparable to those in control and LacZ-transduced cells exposed to hyperoxia. Ultrastructural morphometric analyses demonstrated that mitochondria and endoplasmic reticulum were less swollen in myrAkt cells relative to controls exposed to hyperoxia. These studies demonstrate that early activation of Akt occurs in hyperoxia in HLMVEC. That this event is a beneficial response is suggested by the finding that constitutive activation of Akt protects against hyperoxic stress, at least in part, by maintaining mitochondrial integrity.
Assuntos
Sobrevivência Celular/fisiologia , Hiperóxia/metabolismo , Estresse Oxidativo/fisiologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Células Cultivadas , Endotélio Vascular/metabolismo , Ativação Enzimática , Glucose/metabolismo , Humanos , Pulmão/citologia , Fosforilação/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Transdução GenéticaRESUMO
A catalytic antioxidant, AEOL 10113, was used in a murine model of asthma to test the hypothesis that oxidants contribute to the pathogenesis of asthma. Balb/c mice were immunized and challenged with ovalbumin. AEOL 10113 was administered to the mice by intratracheal instillation during ovalbumin challenges. Enhanced pause as an indicator of airway reactivity and differential cell count of lavage cells as an indicator of airway inflammation were assessed. Lung expressions of the adhesion molecules VCAM-1 and ICAM-1 were measured. We found that treatment of ovalbumin-challenged mice with AEOL 10113 drastically reduced the severity of airway inflammation as evidenced by the reduced numbers of eosinophils, neutrophils, and lymphocytes found in bronchoalveolar lavage fluid. Inhibition of ovalbumin-induced airway inflammation is associated with inhibited expression of VCAM-1, which is a key adhesion molecule responsible for the recruitment of inflammatory cells into the lungs of ovalbumin-challenged mice. In addition, treatment with AEOL 10113 reduced the magnitude of ovalbumin-induced airway hyperreactivity to methacholine. These results suggest that oxidative stress is an important factor in the pathogenesis of asthma and that a synthetic catalytic antioxidant could be effective in the treatment of asthma.
Assuntos
Antioxidantes/uso terapêutico , Asma/tratamento farmacológico , Hiper-Reatividade Brônquica/tratamento farmacológico , Metaloporfirinas/uso terapêutico , Animais , Asma/induzido quimicamente , Asma/metabolismo , Asma/fisiopatologia , Hiper-Reatividade Brônquica/induzido quimicamente , Hiper-Reatividade Brônquica/metabolismo , Hiper-Reatividade Brônquica/fisiopatologia , Líquido da Lavagem Broncoalveolar/citologia , Modelos Animais de Doenças , Eosinófilos/citologia , Molécula 1 de Adesão Intercelular/metabolismo , Linfócitos/citologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Neutrófilos/citologia , Ovalbumina/toxicidade , Molécula 1 de Adesão de Célula Vascular/metabolismoRESUMO
Extracellular superoxide dismutase (EC-SOD) is highly expressed in the extracellular matrix of lung and vascular tissue. Localization of EC-SOD to the matrix of the lung may protect against oxidative tissue damage that leads to pulmonary fibrosis. This study directly examines the protective role of EC-SOD in a bleomycin model of pulmonary fibrosis and the effect of this enzyme on oxidative protein fragmentation. Mice null for ec-sod display a marked increase in lung inflammation at 14 d post-bleomycin treatment as compared to their wild-type counterparts. Hydroxyproline analysis determined that both wild-type and ec-sod null mice display a marked increase in interstitial fibrosis at 14 d post-treatment, and the severity of fibrosis is significantly increased in ec-sod null mice compared to wild-type mice. To determine if the lack of EC-SOD promotes bleomycin-induced oxidative protein modification, 2-pyrrolidone content (as a measure of oxidative protein fragmentation at proline residues) was assessed in lung tissue from treated mice. 2-Pyrrolidone levels in the lung hydrolysates from ec-sod null mice were increased at both 7 and 14 d post-bleomycin treatment as compared to wild-type mice, indicating EC-SOD can inhibit oxidative fragmentation of proteins in this specific model of oxidative stress.
Assuntos
Bleomicina/farmacologia , Espaço Extracelular/enzimologia , Pulmão/efeitos dos fármacos , Pulmão/patologia , Superóxido Dismutase/deficiência , Animais , Líquido da Lavagem Broncoalveolar/química , Colágeno Tipo I/metabolismo , Modelos Animais de Doenças , Hidroxiprolina/análise , Pulmão/química , Pulmão/enzimologia , Pneumopatias/induzido quimicamente , Pneumopatias/enzimologia , Pneumopatias/patologia , Camundongos , Camundongos Transgênicos , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/enzimologia , Fibrose Pulmonar/patologia , Pirrolidinonas/análise , Superóxido Dismutase/metabolismoAssuntos
Antioxidantes/uso terapêutico , Asma/tratamento farmacológico , Hiper-Reatividade Brônquica/prevenção & controle , Catálise/efeitos dos fármacos , Metaloporfirinas/uso terapêutico , Sistema Respiratório/efeitos dos fármacos , Doenças Respiratórias/prevenção & controle , Animais , Modelos Animais de Doenças , Inflamação/prevenção & controle , Camundongos , Camundongos Endogâmicos BALB CRESUMO
Premature newborn baboons [125 d (67%) gestation], exposed to a moderate-size patent ductus arteriosus (PDA) [pulmonary-to-systemic blood-flow-ratio (Qp/Qs) = 1.8] for 14 d, have impaired pulmonary function and arrested alveolar development and surface area when compared with age matched fetuses (140 d gestation). Pharmacologic closure of the PDA reduces the detrimental effects of preterm delivery on pulmonary function and surface area. We used preterm baboons (delivered at 125 d gestation and ventilated for 14 d) to study the effects of surgical PDA ligation on pulmonary function and alveolar surface area. After ligation (on day of life 6), ligated animals had lower Qp/Qs ratios [Qp/Qs (ligated, n = 10) = 1.00 +/- 0.04; (nonligated, n = 12) = 2.05 +/- 0.17; mean +/- SD] and higher systemic blood pressures than nonligated control animals. Ventilation and oxygenation indices did not differ between the groups, during either the pre- or postoperative periods. Alveolar surface area measurements were made by digital image analysis and compared with measurements made from fetal lungs at 125 d (n = 6) and 140 d (n = 7) gestation. PDA ligation failed to improve the postnatal arrest in alveolar surface area. In contrast with pharmacologic closure of the PDA, surgical closure failed to improve either pulmonary function or alveolar surface area in baboons with a moderate PDA shunt.
Assuntos
Procedimentos Cirúrgicos Cardíacos , Permeabilidade do Canal Arterial/cirurgia , Nascimento Prematuro , Alvéolos Pulmonares/crescimento & desenvolvimento , Animais , Pressão Sanguínea , Modelos Animais de Doenças , Permeabilidade do Canal Arterial/tratamento farmacológico , Permeabilidade do Canal Arterial/patologia , Permeabilidade do Canal Arterial/fisiopatologia , Feminino , Idade Gestacional , Ibuprofeno/farmacologia , Ibuprofeno/uso terapêutico , Ligadura , Complacência Pulmonar , Masculino , Papio papio , Alvéolos Pulmonares/efeitos dos fármacos , Alvéolos Pulmonares/embriologia , Alvéolos Pulmonares/patologia , Alvéolos Pulmonares/fisiopatologia , Circulação Pulmonar , Ventilação Pulmonar , Respiração Artificial , Testes de Função Respiratória , Processamento de Sinais Assistido por Computador , Fatores de TempoRESUMO
OBJECTIVE: The goal was to study the pulmonary, biochemical, and morphologic effects of a persistent patent ductus arteriosus in a preterm baboon model of bronchopulmonary dysplasia. METHODS: Preterm baboons (treated prenatally with glucocorticoids) were delivered at 125 days of gestation (term: 185 days), given surfactant, and ventilated for 14 days. Twenty-four hours after birth, newborns were randomly assigned to receive either ibuprofen (to close the patent ductus arteriosus; n = 8) or no drug (control; n = 13). RESULTS: After treatment was started, the ibuprofen group had significantly lower pulmonary/systemic flow ratio, higher systemic blood pressure, and lower left ventricular end diastolic diameter, compared with the control group. There were no differences in cardiac performance indices between the groups. Ventilation index and dynamic compliance were significantly improved with ibuprofen. The improved pulmonary mechanics in ibuprofen-treated newborns were not attributable to changes in levels of surfactant protein B, C, or D, saturated phosphatidylcholine, or surfactant inhibitory proteins. There were no differences in tracheal concentrations of cytokines commonly associated with the development of bronchopulmonary dysplasia. The groups had similar messenger RNA expression of genes that regulate inflammation and remodeling in the lung. Lungs from ibuprofen-treated newborns were significantly drier (lower wet/dry ratio) and expressed 2.5 times more epithelial sodium channel protein than did control lungs. By 14 days after delivery, control newborns had morphologic features of arrested alveolar development (decreased alveolar surface area and complexity), compared with age-matched fetuses. In contrast, there was no evidence of alveolar arrest in the ibuprofen-treated newborns. CONCLUSIONS: Ibuprofen-induced patent ductus arteriosus closure improved pulmonary mechanics, decreased total lung water, increased epithelial sodium channel expression, and decreased the detrimental effects of preterm birth on alveolarization.
Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Permeabilidade do Canal Arterial/tratamento farmacológico , Ibuprofeno/uso terapêutico , Pulmão/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Líquido da Lavagem Broncoalveolar/química , Permeabilidade do Canal Arterial/metabolismo , Permeabilidade do Canal Arterial/fisiopatologia , Canais Epiteliais de Sódio/metabolismo , Água Extravascular Pulmonar/metabolismo , Feminino , Maturidade dos Órgãos Fetais/efeitos dos fármacos , Hemodinâmica , Mediadores da Inflamação/metabolismo , Pulmão/anatomia & histologia , Pulmão/embriologia , Pulmão/fisiologia , Masculino , Papio papio , Fosfatidilcolinas/metabolismo , Proteínas Associadas a Surfactantes Pulmonares/metabolismo , RespiraçãoRESUMO
OBJECTIVE: Using the 125-day baboon model of bronchopulmonary dysplasia treated with prenatal steroid and exogenous surfactant, we hypothesized that a delay of extubation from low tidal volume positive pressure ventilation to nasal continuous positive airway pressure at 5 days (delayed nasal continuous positive airway pressure group) would not induce more lung injury when compared with baboons aggressively weaned to nasal continuous positive airway pressure at 24 hours (early nasal continuous positive airway pressure group), because both received positive pressure ventilation. METHODS AND RESULTS: After delivery by cesarean section at 125 days (term: 185 days), infants received 2 doses of Curosurf (Chiesi Farmaceutica S.p.A., Parma, Italy) and daily caffeine citrate. The delay in extubation to 5 days resulted in baboons in the delayed nasal continuous positive airway pressure group having a lower arterial to alveolar oxygen ratio, high PaCO2, and worse respiratory function. The animals in the delayed nasal continuous positive airway pressure group exhibited a poor respiratory drive that contributed to more reintubations and time on mechanical ventilation. A few animals in both groups developed necrotizing enterocolitis and/or sepsis, but infectious pneumonias were not documented. Cellular bronchiolitis and peribronchiolar alveolar wall thickening were more frequently seen in the delayed nasal continuous positive airway pressure group. Bronchoalveolar lavage levels of interleukin-6, interleukin-8, monocyte chemotactic protein-1, macrophage inflammatory protein-1 alpha, and growth-regulated oncogene-alpha were significantly increased in the delayed nasal continuous positive airway pressure group. Standard and digital morphometric analyses showed no significant differences in internal surface area and nodal measurements between the groups. Platelet endothelial cell adhesion molecule vascular staining was not significantly different between the 2 nasal continuous positive airway pressure groups. CONCLUSIONS: Volutrauma and/or low-grade colonization of airways secondary to increased reintubations and ventilation times are speculated to play causative roles in the delayed nasal continuous positive airway pressure group findings.
Assuntos
Displasia Broncopulmonar/terapia , Pressão Positiva Contínua nas Vias Aéreas , Modelos Animais de Doenças , Desmame do Respirador , Animais , Animais Recém-Nascidos , Displasia Broncopulmonar/patologia , Displasia Broncopulmonar/fisiopatologia , Feminino , Humanos , Recém-Nascido , Masculino , Papio , Fatores de TempoRESUMO
We sought to determine whether the extracellular compartment contributed to seizure-induced superoxide (O2*-) production and to determine the role of the NADPH oxidase complex as a source of this O2*- production. The translocation of NADPH oxidase subunits (p47phox, p67phox and rac1) was assessed by immunoblot analysis and NADPH-driven O2*- production was measured using 2-(4-hydroxybenzyl)-6-(4-hydroxyphenyl)-8-benzyl-3,7-dihydroimidazo [1,2-alpha] pyrazin-3-one-enhanced chemiluminescence. Kainate-induced status epilepticus resulted in a time-dependent translocation of NADPH oxidase subunits (p47phox, p67phox and rac-1) from hippocampal cytosol to membrane fractions. Hippocampal membrane fractions from kainate-injected rats showed increased NADPH-driven and diphenylene iodonium-sensitive O2*- production in comparison to vehicle-treated rats. The time-course of kainate-induced NADPH oxidase activation coincided with microglial activation in the rat hippocampus. Finally, kainate-induced neuronal damage and membrane oxygen consumption were inhibited in mice overexpressing extracellular superoxide dismutase. These results suggest that seizure activity activates the membrane NADPH oxidase complex resulting in increased formation of O2*-.
Assuntos
Espaço Extracelular/enzimologia , Hipocampo/enzimologia , NADPH Oxidases/metabolismo , Convulsões/enzimologia , Superóxido Dismutase/metabolismo , Animais , Hipocampo/patologia , Humanos , Masculino , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Ratos , Ratos Sprague-DawleyRESUMO
Brush cells, also termed tuft, caveolated, multivesicular, and fibrillovesicular cells, are part of the epithelial layer in the gastrointestinal and respiratory tracts. The cells are characterized by the presence of a tuft of blunt, squat microvilli (approximately 120-140/cell) on the cell surface. The microvilli contain filaments that stretch into the underlying cytoplasm. They have a distinctive pear shape with a wide base and a narrow microvillous apex. The function of the pulmonary brush cell is obscure. For this reason, a working group convened on August 23, 2004, in Bethesda, Maryland, to review the physiologic role of the brush (microvillous) cell in normal airways and alveoli and in respiratory diseases involving the alveolar region (e.g., emphysema and fibrosis) and airway disease characterized by either excessive or insufficient amounts of airway fluid (e.g., cystic fibrosis, chronic bronchitis, and exercise-induced asthma). The group formulated several suggestions for future investigation. For example, it would be useful to have a panel of specific markers for the brush cell and in this way separate these cells for culture and more direct examination of their function (e.g., microarray analysis and proteomics). Using quantitative analysis, it was suggested to examine the number and location of the cells in disease models. Understanding the function of these cells in alveoli and airways may provide clues to the pathogenesis of several disease states (e.g., cystic fibrosis and fibrosis) as well as a key for new therapeutic modalities.
Assuntos
Alvéolos Pulmonares/citologia , Mucosa Respiratória/ultraestrutura , Animais , Educação , Humanos , Microscopia Eletrônica , Microvilosidades/fisiologia , Microvilosidades/ultraestrutura , Mucosa Respiratória/fisiologiaRESUMO
Nitric oxide (NO) serves multiple functions in the developing lung, and pulmonary NO production is decreased in a baboon model of chronic lung disease (CLD) after premature birth at 125 days (d) gestation (term = 185d). To determine whether postnatal NO administration alters the genesis of CLD, the effects of inhaled NO (iNO, 5 ppm) were assessed in the baboon model over 14d. iNO caused a decrease in pulmonary artery pressure in the first 2d and a greater rate of spontaneous closure of the ductus arteriosus, and lung compliance was greater and expiratory resistance was improved during the first week. With iNO, postmortem pressure-volume curves were shifted upward, lung DNA content and cell proliferation were increased, and lung growth was preserved to equal that which occurs during the same period in utero. In addition, the excessive elastin deposition characteristic of CLD was normalized by iNO, and there was evidence of stimulation of secondary crest development. Thus, in the baboon model of CLD, iNO improves early pulmonary function and alters lung growth and extracellular matrix deposition. As such, NO biosynthetic pathway dysfunction may contribute to the pathogenesis of CLD.
Assuntos
Animais Recém-Nascidos , Broncodilatadores/administração & dosagem , Elastina/metabolismo , Pneumopatias/fisiopatologia , Pulmão/fisiopatologia , Óxido Nítrico/administração & dosagem , Administração por Inalação , Animais , Broncodilatadores/farmacologia , Doença Crônica , Hemodinâmica/efeitos dos fármacos , Processamento de Imagem Assistida por Computador , Pulmão/crescimento & desenvolvimento , Pulmão/metabolismo , Pulmão/patologia , Pneumopatias/metabolismo , Óxido Nítrico/farmacologia , Tamanho do Órgão/efeitos dos fármacos , Papio , Alvéolos Pulmonares/patologia , Artéria Pulmonar/fisiopatologia , Circulação Pulmonar/efeitos dos fármacosRESUMO
Increased glucose utilization and hexokinase (HK)-II expression are adaptive features of lung cells exposed to hypoxia or hyperoxia. HK-II is the most regulated isoform of HK. Whether its overexpression could be protective against oxidative stress was explored in human lung epithelial-like (A549) cells. HK-II was overexpressed in A549 cells in a tetracycline-repressible retroviral vector system. Elevated expression of HK-II was confirmed by Western blot and activity measurements. Cell death caused by exposure to hyperoxia was decreased in HK-II-overexpressing cells. This effect was reversed when HK-II expression was suppressed with doxycycline. A similar protective effect was observed in HK-II-overexpressing cells after treatment with 1 mM hydrogen peroxide for 48 h. At baseline, fluorescence microscopy showed that overexpressed HK-II was localized to mitochondria. Electron microscopic studies showed that hyperoxia-exposed HK-II overexpressors had better-preserved and quantitatively smaller mitochondria than those in which the HK-II expression was suppressed or in the nontransduced A549 cells. Mitochondrial membrane potential was increased in HK-II-overexpressing cells exposed to hyperoxia compared with the nontransduced control cells under similar conditions. The present study demonstrates that HK-II protects human lung epithelial-like A549 cells against oxidative insults by protecting the mitochondria.
Assuntos
Citoproteção , Hexoquinase/metabolismo , Hiperóxia/metabolismo , Hiperóxia/patologia , Pulmão/metabolismo , Pulmão/patologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Imunofluorescência , Glucose/metabolismo , Humanos , Peróxido de Hidrogênio/farmacologia , Hiperóxia/fisiopatologia , Pulmão/efeitos dos fármacos , Pulmão/fisiopatologia , Potenciais da Membrana/efeitos dos fármacos , Mitocôndrias/fisiologia , Oxidantes/farmacologia , Coloração e RotulagemRESUMO
Hemorrhage results in excessive production of superoxide that is associated with severe lung injury. We examined whether the superoxide dismutase (SOD) mimetic manganese(III) mesotetrakis (di-N-ethylimidazole) porphyrin (AEOL 10150) could attenuate this lung injury and whether extracellular (EC)-SOD-deficient mice would have increased hemorrhage-induced lung injury. Compared with wild-type mice, EC-SOD-deficient mice had increased lung neutrophil accumulation, a 3.9-fold increase in myeloperoxidase activity, a 1.5-fold increase in nuclear factor (NF)-kappaB activation, and a 1.5-fold increase in lipid peroxidation 1 h after hemorrhage. Pretreatment with AEOL 10150 did not attenuate neutrophil accumulation but significantly reduced NF-kappaB activation and lipid peroxidation in both wild-type and EC-SOD-deficient mice. The increase in hemorrhage-induced neutrophil accumulation in the lungs of EC-SOD-deficient mice suggests that EC-SOD might play a role in mediating neutrophil recruitment to the lung.
Assuntos
Hemorragia/metabolismo , Pneumonia/metabolismo , Superóxido Dismutase/metabolismo , Aconitato Hidratase/metabolismo , Animais , Antioxidantes/química , Antioxidantes/farmacologia , Espaço Extracelular/enzimologia , Hemorragia/imunologia , Peroxidação de Lipídeos/efeitos dos fármacos , Metaloporfirinas/química , Metaloporfirinas/farmacologia , Camundongos , Camundongos Knockout , Neutrófilos/citologia , Estresse Oxidativo/efeitos dos fármacos , Pneumonia/tratamento farmacológico , Pneumonia/imunologia , Superóxido Dismutase/genéticaRESUMO
Extracellular superoxide dismutase (EC-SOD) is an abundant antioxidant in the lung and vascular walls. Previous studies have shown that EC-SOD attenuates lung injury in a diverse variety of lung injury models. In this study, we examined the role of EC-SOD in mediating lipopolysaccharide (LPS)-induced lung inflammation. We found that LPS-induced neutrophilic lung inflammation was exaggerated in EC-SOD-deficient mice and diminished in mice that overexpressed EC-SOD specifically in the lung. Similar patterns were seen for bronchoalveolar lavage cytokines, such as tumor necrosis factor-alpha, keratinocyte-derived chemokines, and macrophage inflammatory protein-2 as well as expression of lung intercellular adhesion molecule-1, vascular cell adhesion molecule-1, endothelial cell selectin, and platelet selectin. In a macrophage cell line, EC-SOD inhibited LPS-induced macrophage cytokine release, but did not alter expression of intercellular adhesion molecules in endothelial cells. These results suggest that EC-SOD plays an important role in attenuating the inflammatory response in the lung most likely by decreasing release of proinflammatory cytokines from phagocytes.