ABSTRACT
This chapter focuses on the elevation of calcium levels in tissue culture medium that induces differentiation in colonocytes as it does in other types of epithelial cells. It determines whether decreasing the calcium level to micromolar levels will prevent this differentiation. A method was developed for the routine primary culture of human colonic epithelial cells from biopsies. The cultured cells exhibited characteristic epithelial structures, including a brush border and junctional complexes, as shown by electron microscopy. The serum-free culture method then was used to study the effect of alterations in culture medium calcium levels on the proliferation of isolated colonocytes in primary tissue culture. Calcium complexes of these compounds are readily seen to form and to precipitate out of the culture medium, showing that the protection occurred through a chemical, not a biological, mechanism. While ionized calcium levels are very closely controlled within the blood, the levels in the fecal stream and tissues vary widely.
