Basal processes on duodenal epithelial cells of man, mouse and rat

Localized ischaemia of duodenal mucosa induced either by ligation or cautery of a small branch of the coeliac artery resulted in the loss of epithelial cells of duodenal villi in young mature inbred mice. Biopsies from normal human duodenum and mouse duodenum placed in non-oxygenated physiological saline for 20 min showed a similar loss of epithelial cells. In all cases, scanning electron microscope (SEM) examination revealed that processes extended from the base of epithelial cells through the underlying basement membrane. When duodenal tissues were bathed in solutions of EDTA or sodium azide, basal processes were not seen by SEM. Transmission electron microscopy (TEM) of duodenal tissues from man, rat, and mouse revealed basal processes. Because all duodenal epithelial cells appear to have basal processes, it is proposed that they may play an important role in moving absorbed substances across the villous basement membrane barrier along an intracellular concentration gradient, and in thus facilitating absorption. There are no indications which would suggest that basal processes are the result of a pathological process, and the presence of similar basal processes in other tissues is noted.