Gastric ontogeny: clinical implications

This is the authors' abstract. We don't add key points for this paper.

The delivery of a preterm infant offers a unique opportunity to look directly upon the process of ontogeny, while at the same time organ immaturity is the basis of the clinical problems which challenge neonatal medicine.In recent years our knowledge of foregut ontogeny has increased, together with an increased body of clinical experience, yet the nutritional management of the preterm infant remains a con- tentious area, with wide variations in clinical practice.The compelling evidence of the importance of early nutritional management on neurodevelopmental outcome now focuses the debate sharply.Closer knowledge of the development of functional maturity in the gut may allow more rapid and rational advances to be made.In this paper we discuss the embryology, the development of secretory and digestive function, and the maturation of gastro-oesophageal motor activity as a background to the clinical management of nutrition in the preterm infant. General embryologyThe human stomach develops from a fusiform swelling of the foregut at about 4 weeks' gesta- tion.Originating in the neck, this swelling descends into the abdomen during the next eight weeks.Differential growth rates result initially in the formation of the greater and lesser curvatures, followed by a 900 clockwise rotation of the stomach which occurs at 6 weeks' gestation. 1The stomach is initially lined by stratified2 or pseudostratified3 columnar epithelial cells which are later replaced by cuboidal cells.Gastric pits have developed in the epithelium by 14 weeks' gestation, and develop a mature glandular structure over the following weeks.Structural maturity is reached before the fetus becomes viable, and by 20 weeks' gestation the fetal stomach macroscopically and microscopically resembles that of the newborn infant at term.Nerve fibres reach the gastric primordium at 5 weeks' gestation, four weeks before the first myoblasts are seen, and by 30 weeks' gestation both are morphologically and histologically mature.4