Detrimental Effects of an Inhaled Phosphodiesterase-4 Inhibitor on Lung Inflammation in Ventilated Preterm Lambs Exposed to Chorioamnionitis Are Dose Dependent.
J Aerosol Med Pulm Drug Deliv 2019;
32:396-404. [PMID:
31573405 DOI:
10.1089/jamp.2019.1528]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background: Treatment of bronchopulmonary dysplasia in preterm infants is challenging due to its multifactorial origin. In rodent models of neonatal lung injury, selective inhibition of phosphodiesterase 4 (PDE4) has been shown to exert anti-inflammatory properties in the lung. We hypothesized that GSK256066, a highly selective, inhalable PDE4 inhibitor, would have beneficial effects on lung injury and inflammation in a triple hit lamb model of Ureaplasma parvum (UP)-induced chorioamnionitis, prematurity, and mechanical ventilation. Methods: Twenty-one preterm lambs were surgically delivered preterm at 129 days after 7 days intrauterine exposure to UP. Sixteen animals were subsequently ventilated for 24 hours and received endotracheal surfactant and intravenous caffeine citrate. Ten animals were randomized to receive twice a high (10 μg/kg) or low dose (1 μg/kg) of nebulized PDE4 inhibitor. Results: Nebulization of high, but not low, doses of PDE4 inhibitor led to a significant decrease in pulmonary PDE activity, and was associated with lung injury and vasculitis, influx of neutrophils, and increased proinflammatory cytokine messenger RNA levels. Conclusion: Contrary to our hypothesis, we found in our model a dose-dependent proinflammatory effect of an inhaled highly selective PDE4 inhibitor in the lung. Our findings indicate the narrow therapeutic range of inhaled PDE4 inhibitors in the preterm population.
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