Few comparative and validated reports exist on the isolation and growth of colonoscopically obtained colonic epithelium. The aim of this study was to develop and validate a simple method for the cultivation of colonoscopically obtained colonocytes. Forty patients, who underwent routine colonoscopy and where the diagnosis of irritable bowel syndrome was later reached, were included. Seven colon biopsies were taken and incubated at varying time periods of 10-120 min and temperatures of 4-37 degrees C in a chelating buffer. The epithelium was then harvested and cultivated under three different conditions: 1) on a collagen coating, 2) embedded in a collagen gel, or 3) embedded in a gel put on a porous well insert. The effect of conditioned medium (CM), insulin, transferrin, selenium, and the oxygen content was assessed. Viability was tested by the metabolic dimethylthiazol-diphenyl-tetrazolium bromide assay, by flowcytometry, by phase contrast microscopy, and by transmission electron microscopy. Incubation at 21 degrees C for 75 min gave an optimal yield of 3 x 10(6) (2.0-3.8 x 10(6)) viable epithelial cells in intact crypts per seven biopsies. Embedding of crypts in a collagen gel put on a porous membrane was superior to the other methods applied [P < 0.003; median viability 71% (62-100%) compared with preculture values] after 24 h, which was a 160% increase in viability compared with coat-cultivated cells. CM had similar viability supporting effects to FCS. Other supplements had no effects. A simple method is presented, which makes cultivation of colonocytes obtained at endoscopy possible for up to 72 h.