Restoration of colorectal continuity reverses atrophy in human rectal mucosa.

Cell kinetic activity and adaptive response of rectal mucosa from patients with Hartmann's procedure were studied before and after restoration of colorectal continuity. Patients without colostomy and with normal rectal mucosa were used as controls. Autoradiography of in vitro labeled mucosal samples with [3H]thymidine was used. The proliferative activity in the rectal crypts was estimated by measuring labeling and mitotic indices, total DNA of isolated crypts, and total crypt cell numbers. One hundred forty days after creating a proximal end colostomy, labeling index (P less than 0.05), mitotic index (P less than 0.01), DNA content per crypt (P less than 0.05), and number of cells per crypt (P less than 0.05) decreased significantly compared to control values. Restoration of colorectal continuity resulted in a significant increase of the labeling index (P less than 0.05), the mitotic index (P less than 0.01), the DNA content per crypt (P less than 0.05), and the cell number per crypt (P less than 0.05). There were no significant differences between the postclosure values and the controls. These data indicated that excluding the human rectal mucosa from fecal stream determined a mucosal atrophy that could be reversed by restoration of colorectal continuity.