Effects of Dietary Fibre on Mucosal Cell Proliferation

Abstract

The surface of the human small intestinal mucosa is covered by an array of finger-like or leaf-like processes, the villi. Each villus consists of an inner core of mesenchymal cells, blood and lymph vessels, nerves and connective tissue, and an outer surface layer or sheet of columnar epithelial cells. The epithelium contains both absorptive cells and mucus-secreting goblet cells. Beneath the villi are blind, glandular crypts, which open into the intestinal lumen at the bases of the villi. As early as 1892 the Italian pathologist Bizzozero had recognized that the mucosal surface was a dynamic tissue, containing transient elements or elementi labili, and that the whole structure was constantly in a state of renewal. He was the first to suggest that cells shed into the lumen from the tips of the villi were replaced by new cells migrating outwards from the crypts. This conjecture was confirmed with the advent of modern techniques such as autoradiography, which is used to detect and localize radioactively labelled DNA precursors within cells and tissues.