Epithelial Phenotypic Expression of Human Foetal Gastrointestinal Mucosa: An Immunohistochemical Analysis

Epithelial phenotypic expression in the gastrointestinal mucosa of 20 human foetuses from the 4th to 10th month of gestation was examined immunohistochemically for glycoproteins, enzymes, peptide hormones and serotonin. Goblet cells with neutral and sialomucin and brush-bordered absorptive cells were scattered in the cardia and antrum of the foetal stomach. Lysozyme was present in Paneth cells of the small intestine but not in the colon throughout the foetal period, whereas in the stomach it was seen in the surface epithelium and gastric glands in the second trimester and then became confined to pyloric and cardiac glands with the development of foetus. Secretory component was not detected in the foetal gastric mucosa but expressed in apical and basolateral cell membranes of the intestinal epithelium from the 10th gestational month. Using monoclonal antibody to carcinoembryonic antigen (CEA), only apical and lateral cell membranes of colonic epithelium from the 6th to 8th month of gestation were immunoreactive for CEA, but the stomach and small intestine had no CEA. Alpha-1-antitrypsin and alpha-1-antichymotrypsin were observed scattered in the crypts of the small intestine but were not detected in the stomach and colon. Gastrin containing cells were less in number than somatostatin containing cells in the stomach but dramatically increased from the 8th month of gestation. Serotonin containing cells showed the closed type in the stomach, the open type in the small intestine and both in the colon of the foetus. Glicentin containing cells were present in the fundic mucosa from the 5th to the last gestational month. Calcitonin was not detected in the foetal gut mucosa. These results suggest that the expression of these tissue markers in intestinal metaplasia and adenocarcinoma of the stomach cannot be explained merely by the reversion to the foetal gastric phenotype.