Immunohistochemical study of neuroendocrine cells at the gastric cardia mucosa.

BACKGROUND/AIMS The gastric cardia mucosa is a narrow band of tissue between the oesophagus and the stomach. The physiological role of this tissue is unknown. This study examined the presence and characteristics of neuroendocrine cells at this site. METHODS Biopsy samples were obtained from across normal appearing squamocolumnar junctions. The cardiac mucosa was defined as the presence of special type mucosa composed of mucous secreting glands in the immediate vicinity of oesophageal squamous epithelium. Biopsy specimens were stained with haematoxylin and eosin, alcian blue (pH 2.5) periodic acid Schiff, and modified Giemsa. The chromogranin A and Fontana-Masson stains were used to identify neuroendocrine cells, which were also stained immunohistochemically for gastrin, serotonin, glucagon, pancreatic polypeptide, somatostatin, and vasoactive intestinal peptide. RESULTS Chromogranin positive cells were seen in 18 cases with adequate biopsy specimens from the gastric cardia mucosa. These cells were all serotonin positive, but stains for other peptide hormones remained negative. Serotonin positive cells were detected only at the base of foveolae at the periphery of mucous secreting cardiac glands, giving a microscopic appearance resembling that of endocrine cells at the gastric antrum. The presence and numbers of serotonin positive cells did not correlate with chronic inflammation or intestinal metaplasia of the cardiac mucosa. These cells were seen both in Helicobacter pylori positive and negative patients. CONCLUSIONS Serotonin positive cells appear to be the sole neuroendocrine cell type at the gastric cardia mucosa. These cells may have a role in regulating the physiology of the gastric cardia mucosa and the lower oesophageal sphincter.