Mapping of cell cycle distribution in normal human urinary bladder epithelium.

A method is described by which urothelial cells from well defined areas in the urinary bladder mucosa can be obtained. At cystoscopy epithelial cells are aspirated by means of a ureteral catheter. The cells obtained by this selective sampling technique are well suited for morphology and for quantitative single cell measurements by flow cytometry (FCM). In the present study the cell cycle distribution has been measured by FCM. Twenty-five patients (13 males and 12 females) had urothelial cells collected from well defined areas in the mucosa and the DNA content measured from different sites separately. The distribution of bladder mucosa cells in the different parts of the cell cycle (G1, S-phase and G2 + M) is reported. No significant differences were found with regard to sex and age of the patients. Also, a low regional variation was found in the bladder mucosa indicating that the method should enable the discrimination of even small abnormal cell populations in tumour disease. No evidence of polyploidy in the human urothelium was found.