Intra-amniotic endotoxin induces lung maturation by direct effects on the developing respiratory tract in preterm sheep.

Abstract

OBJECTIVE:

Our purpose was to determine whether improved preterm lung function caused by intraamniotic endotoxin treatment requires endotoxin entry into the respiratory tract.

STUDY DESIGN:

We assessed lung inflammation 2 days after intra-amniotic endotoxin (10 mg, Escherichia coli 055:B5) or saline solution in preterm lambs (123 days' gestation) that had undergone surgery to isolate the gastrointestinal or respiratory systems from the amniotic sac. In other sheep longer-term effects were assessed 7 days after we isolated the fetal respiratory tract and gave endotoxin or saline solution directly to the lungs or into the amniotic sac. We measured pulmonary inflammation, lung function, and surfactant 1 week after treatment (approximately 125 days).

RESULTS:

Pulmonary inflammation was present after intra-amniotic endotoxin only if there was communication between the respiratory tract and the amniotic sac. Lung function was improved and surfactant was increased only in preterm lambs that received direct pulmonary endotoxin.

CONCLUSION:

Endotoxin causes functional improvement of the preterm lung by direct effects on the developing respiratory system.

• Authors: Timothy J M Moss, Ilias Nitsos, Boris W Kramer, Machiko Ikegami, John P Newnham, Alan H Jobe
• Journal: American journal of obstetrics and gynecology (Am J Obstet Gynecol) Vol. 187 Issue 4 Pg. 1059-65 (Oct 2002) ISSN: 0002-9378 [Print] United States
• PMID: 12389005 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Endotoxins
• Pulmonary Surfactants

Topics

• Amnion
• Animals
• Embryonic and Fetal Development
• Endotoxins (administration & dosage, pharmacology)
• Escherichia coli
• Female
• Fetal Organ Maturity (drug effects)
• Fetus (physiology)
• Injections
• Lung (embryology)
• Pneumonia (chemically induced)
• Pregnancy
• Pulmonary Surfactants (metabolism)
• Respiratory System (embryology)
• Sheep