Crypt cell production rates at various sites around the colon in Wistar rats and humans.

The crypt cell production rate (CCPR) is considered the most robust estimate of cell turnover. The CCPR was determined at various sites around the colon in the Wistar rat (using an in vivo technique) and in six healthy humans (using in vitro organ culture). In both the rat and human colon, the CCPR increased proximally from the rectum to the caecum. The caecum had a significantly higher cell turnover than any other site in the colon (p < 0.05 in the rat, p < 0.01 in humans, Student's t test). These findings are of interest when considering cellular proliferation studies in both inflammatory bowel disease and colorectal cancer, and draw attention to the importance of choosing a constant reference site for comparative studies. This is the first time the CCPR had been measured along the length of the human colon.