A 14-kDa cathepsin L-derived carboxyl IGFBP-2 fragment is sequestered by cultured rat ileal crypt cells.

IGF-II gut drives mucosal growth during gestation. IGF binding protein-2 (IGFBP-2) has a high affinity for IGF-II and tightly regulates IGF-II availability during fetal and early neonatal growth. We have previously demonstrated that glucocorticoids alter IGF homeostasis in the neonatal ileum, but the mechanism(s) by which this occurs is poorly understood.

A methodology for distinguishing divergent cell fates within a common progenitor population: adenoma- and neuroendocrine-like cells are confounders of rat ileal epithelial cell (IEC-18) culture.

Background: IEC-18 cells are a non-transformed, immortal cell line derived from juvenile rat ileal crypt cells. They may have experimental advantages over tumor-derived gastrointestinal lineages, including preservation of phenotype, normal endocrine responses and retention of differentiation potential. However, their proclivity for spontaneous differentiation/transformation may be stereotypical and could represent a more profound experimental confounder than previously realized.

Insulin-like growth factor-I governs submucosal growth and thickness in the newborn mouse ileum.

Spontaneous intestinal perforations in extremely premature infants are associated with glucocorticoid-induced thinning of the ileal bowel wall. We have previously demonstrated that insulin-like growth factor-1 (IGF-1) is abundant within the submucosa of the newborn mouse ileum but is diminished by glucocorticoid exposure, concomitant with bowel wall thinning. These findings prompted us to hypothesize that IGF-I governs submucosal growth during neonatal gut development and that diminished IGF-I abundance results in submucosal thinning.

Igf-I accelerates ileal epithelial cell migration in culture and newborn mice and may be a mediator of steroid-induced maturation.

We have previously hypothesized that IGF-I is a mediator of dexamethasone (DEX) effect in the newborn mouse ileum-a model designed to mimic the precocious mucosal maturation associated with spontaneous ileal perforations in extremely premature neonates. We have further investigated this hypothesis using in vivo and in vitro models of accelerated epithelial migration (a transient property, temporally associated with mucosal maturation). These experiments include a steroid-treatment model comparing IGF-I immunolocalization with bromo-deoxyuridine (BrdU)-pulse-labeling, as a means of assessing epithelial cell migration, within the ileum of newborn mice that received either daily intraperitoneal injections of DEX (1 microg/gm) or vehicle.