EFFECTS OF DEXAMETHASONE ON BRONCHOALVEOL AR INFLAMMATORY REACTION INPRETERM INFANTS AT HIGH-RISK FOR BPD

Objectives: Dexamethasone improves lung function in infants with bronc hopulmonary dysplasia (BDP). The mechanism of this action, however, is not clear. In this study we investigated the effects of dexamethasone on bronchoalveolar inflammation and permeability. Methods: 24 very lo w birth weight infants (mean birthweight 892+/-36 g, mean gestational age 27.2+/-0.3 weeks) who developed signs of beginning BPD on day 10 o f postnatal age (FiO2>0.3 and/or PIP> 16 cm H2O), were randomly assign ed to dexamethasone treatment on day 10 or day 16. The effects of this treatment on inflammatory indicators in tracheobronchial secretions w ere evaluated. The following aspects of inflammation were assessed: 1) Chemotactic activity and number of neutrophils in lung effluent fluid . 2) Concentrations of the chemoattractants leukotrien B4, C5a, and in terleukin-8. 3) Concentrations of elastase-alpha1-proteinase inhibitor , and activity of elastase and alpha1-proteinase inhibitor. 4) Concent rations of albumin as a marker of mikrovascular permeability.Results: All inflammatory indicators significantly decreased after, treatment w ith dexamethason on day 10 and 16, with the exception of leukotrien B4 which decreased only after early treatment. Albumin concentrations al so significantly decreased after dexamethasone treatment. Conclusion: Dexamethasone decreases the inflammatory pulmonary response and microv ascular permeability in infants at risk for BPD.