Cell loss from small intestinal mucosa: a morphological study.

Large numbers of cells are shed from small intestinal mucosa but they are so rapidly destroyed that there is little direct information about their morphological types. Material obtained by washing the human and rat small intestine was immediately processed and examined by light and electron microscopy. Small intestinal epithelial cells could not be identified by light microscopy but were readily recognized-by the presence of brush borders-using the electron microscope. Eighty to 85% of the cells from both rats and patients with normal small intestinal mucosa were intestinal absorptive cells. This was also the case in four patients with the coeliac syndrome and flat intestinal mucosa. These findings provide further support for the view that measurements of cell loss using intestinal washing techniques and the DNA-loss method, reflect predominantly small intestinal epithelial cell loss and turnover.