Influence of amnioinfusion in a model of in utero created gastroschisis in the pregnant ewe.
OBJECTIVE: Recent studies on the management of human fetal gastroschisis have produced two major findings: (1) there is an inflammatory response in the amniotic fluid of these fetuses, and (2) amniotic fluid exchange designed to disrupt the inflammatory loop seems to have a favorable impact on the immediate and late outcome of these early operated neonates. To test this hypothesis, we used serial amniotic fluid exchanges in a model of gastroschisis developed in the ewe. METHODS: Gastroschisis was created at midgestation in 21 lamb fetuses by an in utero technique. Saline was amnioinfused in some fetuses every 10 days to term. Fetuses were sacrificed on day 145 by cesarean section. Extra-abdominal bowels with fibrous peel were processed for histologic examination. Comparisons were done between fetuses without gastroschisis (controls), fetuses with gastroschisis and amnioinfusion, and fetuses with gastroschisis without amnioinfusion. RESULTS: Of 21 fetuses operated, 8 died in utero or were stillborn; 5 were not amnioinfused, and 8 underwent amnioinfusion. Thickness of bowel muscularis (micrometer) was 92.6 +/- 20.2 for controls, 126.2 +/- 21 for the amnioinfused fetuses, and 182.8 +/- 58.3 for the nonamnioinfused fetuses (p = 0.001). The same significant results were obtained for thickness of serous fibrosis (p = 0.02) and plasma cell infiltration (p = 0.015). CONCLUSIONS: We have created a model of gastroschisis suitable for experimentation in the fetal sheep. Our amnioinfusion data in this model indicate a clear improvement of the deleterious process. This finding correlates well with recent data on amnioinfusion as a therapeutic approach to human gastroschisis.