Chorioamnionitis-induced fetal gut injury is mediated by direct gut exposure of inflammatory mediators or by lung inflammation.
Intra-amniotic exposure to proinflammatory agonists causes chorioamnionitis and fetal gut inflammation. Fetal gut inflammation is associated with mucosal injury and impaired gut development. We tested whether this detrimental inflammatory response of the fetal gut results from a direct local (gut derived) or an indirect inflammatory response mediated by the chorioamnion/skin or lung, since these organs are also in direct contact with the amniotic fluid. The gastrointestinal tract was isolated from the respiratory tract and the amnion/skin epithelia by fetal surgery in time-mated ewes. Lipopolysaccharide (LPS) or saline (controls) was selectively infused in the gastrointestinal tract, trachea, or amniotic compartment at 2 or 6 days before preterm delivery at 124 days gestation (term 150 days). Gastrointestinal and intratracheal LPS exposure caused distinct inflammatory responses in the fetal gut. Inflammatory responses could be distinguished by the influx of leukocytes (MPO(+), CD3(+), and FoxP3(+) cells), tumor necrosis factor-α, and interferon-γ expression and differential upregulation of mRNA levels for Toll-like receptor 1, 2, 4, and 6. Fetal gut inflammation after direct intestinal LPS exposure resulted in severe loss of the tight junctional protein zonula occludens protein 1 (ZO-1) and increased mitosis of intestinal epithelial cells. Inflammation of the fetal gut after selective LPS instillation in the lungs caused only mild disruption of ZO-1, loss in epithelial cell integrity, and impaired epithelial differentiation. LPS exposure of the amnion/skin epithelia did not result in gut inflammation or morphological, structural, and functional changes. Our results indicate that the detrimental consequences of chorioamnionitis on fetal gut development are the combined result of local gut and lung-mediated inflammatory responses.
Division of Neonatology, the Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati School of Medicine, Cincinnati, Ohio;
Tim G A M
TG
Wolfs
Boris W
BW
Kramer
Geertje
G
Thuijls
Matthew W
MW
Kemp
Masatoshi
M
Saito
Monique G M
MG
Willems
Paranthaman
P
Senthamarai-Kannan
John P
JP
Newnham
Alan H
AH
Jobe
Suhas G
SG
Kallapur
D000653:Amniotic Fluid; D000818:Animals; D002454:Cell Differentiation; D049109:Cell Proliferation; D002821:Chorioamnionitis / Q000139:chemically induced / Q000473:pathology*; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects; D005260:Female; D005315:Fetal Diseases / Q000139:chemically induced / Q000209:etiology*; D005767:Gastrointestinal Diseases / Q000196:embryology / Q000209:etiology* / Q000473:pathology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D007079:Ileitis / Q000139:chemically induced / Q000196:embryology / Q000473:pathology; D007082:Ileum / Q000196:embryology / Q000473:pathology; D007249:Inflammation / Q000139:chemically induced / Q000150:complications / Q000473:pathology; D007413:Intestinal Mucosa / Q000166:cytology; D008070:Lipopolysaccharides / Q000633:toxicity; D011014:Pneumonia / Q000139:chemically induced / Q000150:complications* / Q000473:pathology; D011247:Pregnancy; D011897:Random Allocation; D012756:Sheep; D050378:T-Lymphocytes, Regulatory; D051193:Toll-Like Receptors
D016207:Cytokines; D008070:Lipopolysaccharides; D051193:Toll-Like Receptors
endotoxin; fetal inflammatory response; necrotizing enterocolitis; sheep