Intestinal stem cells contribute to the maturation of the neonatal small intestine and colon independently of digestive activity

The murine intestine, like that of other mammalians, continues to develop after birth until weaning; however, whether this occurs in response to an intrinsic developmental program or food intake remains unclear. Here, we report a novel system for the allotransplantation of small intestine and colon harvested from Lgr5^{EGFP-IRES-CreERT2/+}; Rosa26^rbw/+ mice immediately after birth into the subrenal capsule of wild-type mice. By histological and immunohistochemical analysis, the developmental process of transplanted small intestine and colon was shown to be comparable with that of the native tissues: mature intestines equipped with all cell types were formed, indicating that these organs do not require food intake for development. The intestinal stem cells in transplanted tissues were shown to self-renew and produce progeny, resulting in the descendants of the stem cells occupying the crypt-villus unit of the small intestine or the whole crypt of the colon. Collectively, these findings indicate that neonatal intestine development follows an intrinsic program even in the absence of food stimuli.