Expansion of intestinal stem cells associated with long-term adaptation following ileocecal resection in mice

Abstract

Sustained increases in mucosal surface area occur in remaining bowel following massive intestinal loss. The mechanisms responsible for expanding and perpetuating this response are not presently understood. We hypothesized that an increase in the number of intestinal stem cells (ISC) occurs following intestinal resection and is an important component of the adaptive response in mice. This was assessed in the jejunum of mice 2-3 days, 4-5 days, 6-7 days, 2 wk, 6 wk, and 16 wk following ileocecal resection (ICR) or sham operation. Changes in ISC following ICR compared with sham resulted in increased crypt fission and were assayed by 1) putative ISC population (SP) by flow cytometry, 2) Musashi-1 immunohistochemistry, and 3) bromodeoxyuridine (BrdU) label retention. Observed early increases in crypt depth and villus height were not sustained 16 wk following operation. In contrast, long-term increases in intestinal caliber and overall number of crypts per circumference appear to account for the enhanced mucosal surface area following ICR. Flow cytometry demonstrated that significant increases in SP cells occur within 2-3 days following resection. By 7 days, ICR resulted in marked increases in crypt fission and Musashi-1 immunohistochemistry staining. Separate label-retention studies confirmed a 20-fold increase in BrdU incorporation 6 wk following ICR, confirming an overall increase in the number of ISC. These studies support that expansion of ISC occurs following ICR, leading to an overall increase number of crypts through a process of fission and intestinal dilation. Understanding the mechanism expanding ISCs may provide important insight into management of intestinal failure.

Cell dynamics in fetal intestinal epithelium: implications for intestinal growth and morphogenesis

“…Numerous studies in rat, mouse, sheep, pig and rabbit have characterized the intestinal epithelium as stratified prior to villus remodeling (Cervantes et al, 2008;de Santa Barbara et al, 2003;Dekaney et al, 1997;Dekaney et al, 2007;Hashimoto et al, 1999;Kim et al, 2007;Madara et al, 1981;Mathan et al, 1976;Saotome et al, 2004;Sbarbati, 1982;Toofanian and Targowski, 1982;Toyota et al, 1989). In all of these studies, the histological and microscopic techniques used were unable to capture the entirety of the extremely long, thin epithelial cells that stretch from the basal to apical surfaces.…”

Recent insights into the integration of the intestinal epithelium within the mucosal environment in health and disease

“…Toward this goal, steps have been taken to isolate and characterize ISCs. Sorting of " side population " cells yielded a side population fraction that is far from pure, 19,20 but it appears that the number of CD45-negative side population cells is a reasonable surrogate for stem cell number. 21 Development of better isolation methods and functional assays of ISCs remains a pivotal challenge.…”

Murine Ileocolic Bowel Resection with Primary Anastomosis

“…The principles of this procedure may also apply to other models of disease. By removing 50% of the small bowel with ileocolic anastomosis, mouse models have been used to investigate the adaptive intestinal growth response in short gut syndrome [4][5][6] . In the future this may also become a useful model for studying the systemic and local effects of surgery in colorectal cancer.…”

“…They concluded that feeding with liquid diet in the perioperative period and using 9-0 monofilament sutures resulted in an optimal post-operative survival of 88%. Since this initial publication, ICR in mice removing 50% of the small bowel has been used in several studies to explore the dynamics of massive small bowel resection and the adaptive growth response in attempt to develop new therapies for short gut syndrome 5,6 . The first application of the ICR mouse model to Crohn's disease used the IL-10 -/-mouse model, which spontaneously develops colitis 7 .…”