Kallapur SG, Nitsos I, Moss TJM, Polglase GR, Pillow JJ, Cheah FC, Kramer BW, Newnham JP, Ikegami M, Jobe AH. IL-1 mediates pulmonary and systemic inflammatory responses to chorioamnionitis induced by lipopolysaccharide.
Am J Respir Crit Care Med 2009;
179:955-61. [PMID:
19234101 DOI:
10.1164/rccm.200811-1728oc]
[Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
RATIONALE
Chorioamnionitis frequently associates with preterm delivery and increased amniotic fluid IL-1, and causes fetal lung and systemic inflammation. However, chorioamnionitis is also associated with a paradoxical reduction in the incidence of surfactant deficiency-related respiratory distress syndrome in preterm infants.
OBJECTIVES
To identify the role of IL-1 signaling in the mediation of pulmonary and systemic inflammation and lung maturation in a fetal sheep model of lipopolysaccharide (LPS) induced chorioamnionitis.
METHODS
After confirming the efficacy of recombinant human IL-1 receptor antagonist (rhIL-1ra), fetal sheep were exposed to intraamniotic (IA) injections of Escherichia coli LPS with or without prior IA injections of rhIL-1ra. Preterm lambs were delivered at 82% of term gestation.
MEASUREMENTS AND MAIN RESULTS
rhIL-1ra decreased IA LPS-induced lung inflammation assessed by decreased lung neutrophil and monocyte influx, inducible nitric oxide synthase expression, lung IL-6 and IL-1beta mRNA expression, and airway myeloperoxidase concentrations. rhIL-1ra inhibited IA LPS-induced fetal systemic inflammation assessed by decreased plasma IL-8, protein carbonyls, blood neutrophilia, and the expression of serum amyloid A3 mRNA in the liver. rhIL-1ra also partially blocked the lung maturational effects of IA LPS. Therefore blockade of IL-1 signaling in the amniotic compartment inhibited fetal lung and systemic inflammation and lung maturation in response to LPS-induced chorioamnionitis.
CONCLUSIONS
IL-1 plays a central role in the pathogenesis of chorioamnionitis-induced fetal inflammatory responses.
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