Bronchopulmonary dysplasia (BPD) is a chronic lung disease that affects prematurely born infants and appears to evolve in part from early inflammatory responses in the lung. The inflammatory responses have been associated with protein and lipid oxidation in tracheal aspirate fluids. The present study was designed to test the hypothesis that in the first week of life specific oxidations and/ or altered expressions of proteins would be observed in tracheal aspirate fluids in infants who would subsequently develop BPD. We obtained tracheal aspirate fluids on Days of life 1, 3, and 6 from infants born at < or = 29 wk gestation, incubated the fluids with 2,4-dinitrophenylhyrazine (DNPH), separated the proteins electrophoretically, and assessed DNPH reactivity by immunonblots. DNPH reactivity of a protein that was identified as Clara cell secretory protein (CCSP) was observed more consistently in tracheal aspirate fluids from infants who later developed BPD than from infants who did not develop BPD. Tracheal aspirate fluid levels of immunoreactive CCSP were also lower on Day of life 1 in infants who developed BPD than in those who did not develop BPD. Increased CCSP oxidation and decreased immunoreactive CCSP expression in infants who subsequently developed BPD suggest that Clara cell function and CCSP expression may be critical for normal bronchoalveolar fluid homeostasis and that maintaining CCSP expression and function may be useful goals for targeted therapies for inhibition of the development of BPD.

Bronchopulmonary dysplasia (BPD) is recognized as an important cause of morbidity and mortality in preterm infants. Because the role of congenital infections in BPD has been debated, the purpose of this study was to test the hypothesis that detection of infectious agents in tracheal aspirate samples was associated with the development of BPD. Tracheal aspirate samples were obtained within the 1st week of life and screened by polymerase chain reaction for adenovirus, cytomegalovirus, parvovirus, enteroviruses, Ureaplasma urealyticum, Mycoplasma hominis, Mycoplasma pneumoniae, and Chlamydia species. BPD was defined as persistent oxygen dependence at 28 d of age and 36 wk postconceptional age (PCA). Infants that expired before these time points were excluded from statistical analysis. Out of 89 infants studied, at 28 d of life, 13 had expired, 45 had BPD, and 31 had no BPD (controls). At 36 wk PCA, 15 infants expired, 39 still had BPD, and 35 did not. A significant increase in the frequency of adenovirus genome was identified in BPD patients compared with controls, both at 28 d of life (12/45 = 27% versus 1/31 = 3%: p< or =0.01) and at 36 wk PCA (10/39 = 29% versus 2/35 = 6%: p = 0.01). Other microorganisms were rarely detected and not associated with the development of BPD. This is the first study reporting the frequency of detection of adenovirus DNA in tracheal aspirate samples obtained during the 1st week of life from infants with BPD and suggests that prenatal acquisition may be important in the development of BPD.

Because neutrophil attachment to endothelial cell adhesion molecules is a key event in the initiation of an inflammatory response, the association of higher early concentrations of soluble E-Selectin with the development of BPD suggests that E-Selectin may play a key role in the pathogenesis of lung inflammation and the development of BPD. This association also suggests that inflammatory events or effects leading to inflammatory responses occurring in the prenatal and/or very early perinatal periods contribute significantly to the pathogenesis of BPD.

Interferon gamma (IFN-gamma), a potent cytokine inducing a wide range of immunologic activities, is increased in the airway secondary to viral infection or during an inflammatory response. This increase in IFN-gamma concentration may alter the expression of specific airway epithelial cell genes that regulate adaptation of airway inflammatory responses. One protein induced by IFN-gamma is Clara cell secretory protein (CCSP), which may contribute to the attenuation of airway inflammation. This study was done to investigate the molecular mechanism by which IFN-gamma stimulates the expression of the CCSP gene in mouse transformed Clara cells and transgenic mice. Deletion mapping and linker-scanning mutations demonstrated that IFN-gamma-induced expression of CCSP was regulated, in part, at the level of transcription. In vitro and in vivo studies verified that the minimal IFN-gamma-responsive segment was localized to the proximal 166 bp of the 5'-flanking region. Additionally, IFN-gamma-induced expression of CCSP was mediated indirectly through an interferon regulatory factor-1-mediated increase in hepatocyte nuclear factor-3beta.

Uteroglobin/CCSP is expressed specifically in the Clara cells. This allows the gene to be used as a marker to identify the elements regulating the physiologic and cell-specific expression of this gene. The regulation of UG/ CCSP by IFN-␥ was shown to be at the level of the proximal promoter by the upregulation of HNF3␤. This has allowed the determination of the factors responsible for the expression of UG/CCSP.

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Coenzyme A (CoASH) is compartmentalized preferentially in the mitochondria, and CoASH and its mixed disulfide with glutathione (CoASSG) undergo thiol/disulfide exchange reactions with glutathione (GSH) and glutathione disulfide (GSSG) in vitro. We measured CoASH and CoASSG in freeze-clamped lung tissues from Fischer-344 and Sprague-Dawley rats maintained in room air or exposed to Ͼ95% O 2 for 48 h to test the hypothesis that oxidant stresses on lung thiol status would be observed in the CoASH/CoASSG redox couple, suggesting oxidant stress responses in the mitochondria. Lung tissue concentrations of CoASSG in the Fischer-344 rats declined from 0.89 Ϯ 0.15 to 0.51 Ϯ 0.13 nmol/g of lung after 48 h of hyperoxia. CoASH levels declined from 6.40 Ϯ 0.84 to 3.0 Ϯ 0.65 nmol/g of lung, and acetyl CoA levels also were lower in the lungs of animals exposed to hyperoxia. CoASH/CoASSG ratios were lower in animals exposed to hyperoxia, satisfying our previously defined criteria for an oxidant stress on this thiol/disulfide redox couple, but absolute CoASSG levels were not increased, as would be expected for oxidant stresses driven simply by increases in reactive oxygen species or other oxidants. Pulmonary edema was observed in the hyperoxic rats and accounted for some of the declines in CoASH concentrations, but CoASH contents per total lung also declined. Lung mitochondrial succinate dehydrogenase activities were not diminished in rats exposed to hyperoxia, indicating that the decreases in CoASH concentrations are not attributable to general destruction of lung mitochondria. Lung GSSG contents were greater in the hyperoxia animals, but GSH/GSSG ratios, which are dominated by extramitochondrial pools, did not decrease in these animals. The mechanisms responsible for, and the possible pathophysiologic consequences of, the decreases in lung CoASH concentrations are not evident from the data available at the present time, but the loss of more than half the tissue contents of CoASH is likely to generate additional metabolic effects that could have significant pathophysiologic consequences. Administration of supplemental oxygen remains an important therapy in the care of patients with pulmonary insufficiency, as is encountered in many prematurely born infants or in adults with acute respiratory distress. However, this supplemental oxygen can cause adverse effects, as has been observed in the lungs of experimental animals and humans exposed to elevated oxygen tensions (1-4). Cellular injury is manifested when the rates of generation of the reactive species are increased beyond the capacities of the antioxidant defense mechanisms, such as with exposure to hyperoxia (1,5,6), or when the functions of the antioxidant defense mechanisms are deficient, compromised, or developmentally unprepared, such as in prematurely born infants (3,7,8).In the course of exposure of experimental animals to Ͼ95% oxygen, a relatively prolonged period usually is observed in

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