RESTITUTION OF SWALLOWING IN THE FETAL SHEEP RESTORES INTESTINAL GROWTH AFTER MIDGESTATION ESOPHAGEAL OBSTRUCTION

We have shown that, in the fetal sheep, abolition of fluid ingestion e arly in gestation results in a profound gastrointestinal tract (GIT)-s pecific growth retardation and that these effects can be reversed if f etal swallowing is restored, even for relatively short periods (15 day s). The fetal esophagus was ligated at 60-65 days of gestation in 11 f etal sheep (term is 145-148 days). At 136 days of gestation, body and tissue growth of six fetuses were compared to eight age-matched contro l fetuses. There were no effects on body growth, but the growth of the GIT was significantly retarded. The small intestine was the most seve rely affected region; villi were smaller in both proximal and distal r egions, and villus density was increased and crypt density decreased. The growth retarding effects are progressive such that they become mor e pronounced as the period of absence of swallowed input to the GIT is increased. Thus the effects observed in our study (ingestion abolishe d for similar to 80 days) are much more marked than those in our earli er short-term studies (40-50 days). Five of the fetuses with esophagea l ligations underwent further surgery at similar to 120 days' gestatio n to correct the esophageal obstruction so as to allow the resumption of fluid ingestion. By 136 days, the values of most intestinal morphol ogical parameters had begun to move toward control values. It is likel y that tissue growth factors or nutritional factors present in swallow ed fluid and/or the processes involved in the throughput of ingesta ar e involved in the regulation of GIT development before birth.