In vitro growth techniques for intestinal crypts and single intestinal stem cells have been recently described, but several questions of translational importance remain unaddressed. The purpose of this study was to: first, evaluate if intestinal crypts reproducibly expand in vitro; second, determine the impact of age and region of intestine on crypt growth in vitro; and third, determine the effects of cryopreservation on crypt growth in vitro.
Methods and Materials
Crypts were harvested, from 5 cm of proximal, middle and distal small intestine of C57BL/6J mice aged 4wk, 6-8wk, 12-14wk, and 18-20wk (n = 4-6 animals), and cultured. For each region, we determined the efficiency of crypts forming enterospheres (Day 1), and progressing to enteroids (Day 7). Subsequently, enteroids were passaged and cryopreserved to determine if growth was changed by these manipulations.
43-99% of intestinal crypts formed enterospheres, with higher efficiency in proximal small intestine and in younger mice. 25-64% of enterospheres progressed to budding enteroids within 7 days. In vitro expansion was greater in proximal enteroids. This expansion continued in a logarithmic fashion, with ~97% replating efficiency of isolated enteroid crypt buds. Following cryopreservation, ~90% of enteroids recovered normal proliferative capacity.
Intestinal crypt culture is efficient and significantly expands intestinal tissue in a reproducible manner. Regional and age growth differences may reflect distinct stem cell characteristics or differences in support cells. The ability to culture and expand intestinal tissue in vitro provides a potential translational approach toward understanding and treating patients with short bowel syndrome.