RESUMEN
1. In systemic vessels, haem-oxygenase (HO) is induced during oxidative stress and known to modulate vasodilatation and vascular remodelling. At birth, with the transition from placental to air breathing, the pulmonary vessels are exposed to oxidative stress and undergo well-documented remodelling processes. Thus, we investigated the role of HO in the lung during adaptation to extra-uterine life using a pig and mouse model. In addition to the novel data presented with regard to one isoform, HO-1, this study is among the first to describe the pulmonary vascular remodelling in the mouse after birth. 2. We show, for the first time, that another isoform, HO-2, is present constitutively at birth and HO-1 protein is induced in the porcine and murine lung after birth in vascular and airway structures, peaking at 14 days in the pig and at about 4 days in the mouse. Furthermore, we show that HO-1 mRNA declines after birth in the mouse lung. 3. Inhibitors of HO did not modify vasodilator responses in vessels from 14-day-old pigs. 4. Moreover, lungs from HO-1-deficient mice developed normally after birth. 5. HO-1 is induced at birth but plays no role in the development of vasodilator responses or remodelling that occurs at this time. These data suggest that HO-1 expression at birth is a redundant response to oxidative stress in the lungs of healthy mammals. However, it remains possible that this pathway protects if complications occur during or after birth.
Asunto(s)
Adaptación Fisiológica/fisiología , Hemo Oxigenasa (Desciclizante)/biosíntesis , Pulmón/fisiología , Contracción Muscular/fisiología , Arteria Pulmonar/fisiología , Fenómenos Fisiológicos Respiratorios , Animales , Animales Recién Nacidos , Western Blotting , Hemo Oxigenasa (Desciclizante)/genética , Hemo-Oxigenasa 1 , Pulmón/irrigación sanguínea , Pulmón/enzimología , Pulmón/crecimiento & desarrollo , Proteínas de la Membrana , Ratones , Ratones Noqueados , Músculo Liso Vascular/crecimiento & desarrollo , Músculo Liso Vascular/fisiología , Arteria Pulmonar/crecimiento & desarrollo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , PorcinosRESUMEN
OBJECTIVE: We aimed to quantify concentrations of inducible heme oxygenase (HO)-1 in the lungs of patients with acute respiratory distress syndrome (ARDS) and to investigate its role as a source of ferrous iron and as a signaling agent for iron regulation. Control of such processes by heme oxygenase has implications for the onset, progression, and resolution of ARDS. DESIGN: Retrospective analysis of archived samples. SETTING: Adult intensive care unit of a postgraduate teaching hospital. PATIENTS: Patients admitted to the adult intensive care unit who fulfilled the American-European Consensus Conference criteria for ARDS. INTERVENTIONS: Biochemical and immunohistochemical studies using bronchoalveolar lavage fluid or lung tissue were performed in patients with established ARDS and in those undergoing lung resection (controls). MEASUREMENTS AND MAIN RESULTS: Concentrations of heme oxygenase protein were significantly elevated in lung tissue (193.7 +/- 13.27 vs. 81.0 +/- 16.0%, p < .01) and in bronchoalveolar lavage fluid (2.4 x 10(5) vs. 1.4 x 10(5) densitometric units, p = .047) taken from patients with ARDS compared with controls. Concentrations of heme oxygenase protein in bronchoalveolar lavage fluid from patients with ARDS correlated positively and significantly with changes in the concentrations of ferritin (r = .697, p = .02) and the iron saturation of transferrin (r = .8, p = .014) but correlated negatively and significantly with concentrations of bleomycin-detectable (redox-active) iron (r = -.73, p = .031). Significantly elevated (p < .05) concentrations of heme oxygenase staining in cell types expressing this protein were detected in patients with ARDS, compared with concentrations in the same cells taken from controls undergoing lung resection. CONCLUSIONS: Heme oxygenase protein is elevated in the lungs of patients with ARDS and may contribute to the changes in iron mobilization, signaling, and regulation seen in this condition.
Asunto(s)
Hemo Oxigenasa (Desciclizante)/análisis , Pulmón/enzimología , Síndrome de Dificultad Respiratoria/metabolismo , Adulto , Anciano , Western Blotting , Líquido del Lavado Bronquioalveolar , Causalidad , Progresión de la Enfermedad , Femenino , Ferritinas/análisis , Ferritinas/metabolismo , Hemo-Oxigenasa 1 , Homeostasis , Hospitales de Enseñanza , Humanos , Técnicas para Inmunoenzimas , Inmunohistoquímica , Hierro/análisis , Hierro/metabolismo , Proteínas Reguladoras del Hierro/análisis , Proteínas Reguladoras del Hierro/metabolismo , Pulmón/química , Masculino , Proteínas de la Membrana , Persona de Mediana Edad , Oxidación-Reducción , Síndrome de Dificultad Respiratoria/etiología , Síndrome de Dificultad Respiratoria/patología , Estudios Retrospectivos , Transducción de Señal , Transferrina/análisis , Transferrina/metabolismoRESUMEN
Endothelin-1 is a potent vasoconstrictor with mitogenic properties. This 21-amino-acid protein, released in the vasculature by endothelial and smooth muscle cells, has been implicated in pulmonary hypertension. More recently, evidence has accumulated for a role of the heme oxygenase system in pulmonary hypertension. Heme oxygenase catalyses the breakdown of heme to produce carbon monoxide, biliverdin and free iron. Here we show that a carbon monoxide-releasing molecule, but not biliverdin, inhibits endothelin-1 release from serum-stimulated human pulmonary artery smooth muscle cells. Under certain conditions, carbon monoxide appears to act as an endogenous break on endothelin-1 release.
Asunto(s)
Monóxido de Carbono/metabolismo , Endotelina-1/metabolismo , Miocitos del Músculo Liso/metabolismo , Arteria Pulmonar/metabolismo , Biliverdina/metabolismo , Biliverdina/farmacología , Monóxido de Carbono/farmacología , Células Cultivadas , Hemo Oxigenasa (Desciclizante)/metabolismo , Humanos , Interferón gamma/farmacología , Miocitos del Músculo Liso/citología , Arteria Pulmonar/citología , Suero , Factor de Necrosis Tumoral alfa/farmacologíaRESUMEN
Heme oxygenase is the rate-limiting enzyme in the catabolism of heme to carbon monoxide, bilirubin and free iron. Many cell types express heme oxygenase-2 constitutively while heme oxygenase-1 is induced at sites of inflammation and oxidative stress. In systemic blood vessels, carbon monoxide may have an important homeostatic role where, like its better-studied counterpart nitric oxide, it is emerging as a vasodilator and an inhibitor of proliferation. However, much less is known regarding the role of heme oxygenase and carbon monoxide in the pulmonary circulation where vascular responses are very different. Here, using primary cultures of human pulmonary artery smooth muscle cells, we present novel data showing that this cell type expresses heme oxygenase-2 constitutively and, in the presence of oxidants, can induce heme oxygenase-1. We also show that the carbon monoxide-releasing molecule, tricarbonyldichlororuthenium (II) dimer, potently and profoundly inhibits proliferation of human pulmonary artery smooth muscle cells. Pulmonary hypertension is a disease characterised by abnormal vascular smooth muscle cell growth and remodelling of the pulmonary vasculature. Our observations support the growing evidence that the heme oxygenase/carbon monoxide system may play a role in the pathology of pulmonary hypertension.
Asunto(s)
Monóxido de Carbono/fisiología , Hemo Oxigenasa (Desciclizante)/biosíntesis , Músculo Liso Vascular/enzimología , Arteria Pulmonar/enzimología , Western Blotting , Monóxido de Carbono/metabolismo , División Celular , Supervivencia Celular , Células Cultivadas , Hemo-Oxigenasa 1 , Humanos , Proteínas de la Membrana , Músculo Liso Vascular/ultraestructura , Arteria Pulmonar/ultraestructuraRESUMEN
Cytokine-stimulated vascular smooth muscle cells release the colony-stimulating factors (CSFs) granulocyte macrophage-CSF and granulocyte-CSF. We have investigated the effects of a range of cytokines on the release of CSFs from human vascular smooth muscle cells stimulated with interleukin-1beta. Interleukin-4 suppressed granulocyte macrophage-CSF release but potentiated granulocyte-CSF release; interferon-gamma inhibited the release of both, whilst interleukin-5 had no effect. Both interleukin-10 and interleukin-13 inhibited granulocyte macrophage-CSF release but did not affect granulocyte-CSF release. The ability of individual cytokines to differentially modulate CSFs has profound consequences for the populations of leukocytes present at the site of inflammation.