Selective IL-1α exposure to the fetal gut, lung, and chorioamnion/skin causes intestinal inflammatory and developmental changes in fetal sheep

Lab Invest. 2016 Jan;96(1):69-80. doi: 10.1038/labinvest.2015.127. Epub 2015 Oct 26.

Abstract

Chorioamnionitis, caused by intra-amniotic exposure to bacteria and their toxic components, is associated with fetal gut inflammation and mucosal injury. In a translational ovine model, we have shown that these adverse intestinal outcomes to chorioamnionitis were the combined result of local gut and pulmonary-driven systemic immune responses. Chorioamnionitis-induced gut inflammation and injury was largely prevented by inhibiting interleukin-1 (IL-1) signaling. Therefore, we investigated whether local (gut-derived) IL-1α signaling or systemic IL-1α-driven immune responses (lung or chorioamnion/skin-derived) were sufficient for intestinal inflammation and mucosal injury in the course of chorioamnionitis. Fetal surgery was performed in sheep to isolate the lung, gastrointestinal tract, and chorioamnion/skin, and IL-1α or saline was given into the trachea, stomach, or amniotic cavity 1 or 6 days before preterm delivery. Selective IL-1α exposure to the lung, gut, or chorioamnion/skin increased the CD3+ cell numbers in the fetal gut. Direct IL-1α exposure to the gut impaired intestinal zonula occludens protein-1 expression, induced villus atrophy, changed the expression pattern of intestinal fatty acid-binding protein along the villus, and increased the CD68, IL-1, and TNF-α mRNA levels in the fetal ileum. With lung or chorioamnion/skin exposure to IL-1α, intestinal inflammation was associated with increased numbers of blood leukocytes without induction of intestinal injury or immaturity. We concluded that local IL-1α signaling was required for intestinal inflammation, disturbed gut maturation, and mucosal injury in the context of chorioamnionitis.

MeSH terms

  • Animals
  • Chorioamnionitis / immunology*
  • Cytokines / immunology
  • Cytokines / metabolism
  • Disease Models, Animal
  • Female
  • Fetus / immunology*
  • Interleukin-1alpha / immunology*
  • Interleukin-1alpha / metabolism*
  • Intestinal Mucosa / immunology*
  • Lung / immunology*
  • Pregnancy
  • Sheep
  • Skin / immunology

Substances

  • Cytokines
  • Interleukin-1alpha