Iatrogenic gastroschisis in an ovine model of left-sided congenital diaphragmatic hernia

To assess the effect of an iatrogenic gastroschisis on fetal pulmonary growth in an animal model of congenital left-sided diaphragmatic hernia (CDH).

Eighteen time-dated ewes were studied: Group I: healthy controls (H); Group II: CDH controls (untreated) (CDH); Group III: CDH and iatrogenic gastroschisis (CDH+GS). CDH was created in Groups II and III at a mean gestational age of 85 days as previously described. In Group III, a gastroschisis was created concomitantly with the creation of the CDH. A silo was placed around the intestines during the creation of the gastroschisis. Outcome variables included the lung-to-body weight ratio (LBWR) in unfixed and fixed lungs, as well as histological right and left radial alveolar counts (RAC), as previously described.

One animal miscarried, leaving 17 for analysis. One ewe had a twin gestation of which one fetus died in the womb after CDH creation, and the co-twin was used as a healthy control, leaving 17 fetuses for analysis. In six of the 8 ewes with CDH+GS, the silo prevented the intestines from protruding outside the abdomen. However, the CDH was confirmed in all 8 fetuses. Therefore, 6 fetuses with a failed gastroschisis but with a persistent CDH were crossed over to Group II (CDH), while the other two were kept in Group III. In three subsequent ewes, the silo was not placed during the creation of the gastroschisis (CDH+GS without silo). This resulted in 4 fetuses in Group I (H), 8 fetuses in Group II (CDH), and 5 fetuses in Group III (CDH+GS). The LBWR was significantly smaller in Group II, compared to the other two groups. There was no difference in the LBWR between groups I and III. In Group III, the LBWR in the fixed lungs was significantly higher than in Group II, and had a tendency to be significantly different in the unfixed lung (p = 0.057). The right and left RAC were significantly smaller in Group II compared to groups I and III, whereas they were not different between groups I and III. The RAC in Group III was significantly higher in Group III compared to Group II. The intestine of two CDH+GS fetuses was analyzed and showed fibrous tissue with chronic inflammation.

Gastroschisis prevents the development of pulmonary hypoplasia in an ovine model of CDH. Further studies are warranted to confirm these findings.