Embryonic stem cells ameliorate piroxicam-induced colitis in IL10-/- KO mice.

The primary objective of this work is to determine the repairing potential of murine embryonic stem cells (ES) in murine model of Crohn's disease (CD). Colitis, induced in IL10-/- KO mice using piroxicam, was associated with the increased levels of IL-12. Enhanced yellow fluorescent protein (EYFP) marked murine ES cells (R1/129) and control non-fluorescent ES cells were subjected to in vitro differentiation into intestinal epithelial cells. IL 10-/- KO mice were injected with pre-differentiated ES-YFP cells and sacrificed after 2 and 3 months. Histopathological analysis of intestines demonstrated a progressive improvement in colitis (from grade-4 to grade-1 and -0) and decreased levels of IL-12 cytokine following transplantation. Fluorescent and confocal microscopy demonstrated presence of ES-EYFP cells in the colon, small intestine, liver, and thymus tissues but none in the spleen and bone marrow. The EYFP signal was not detected in sham (non-transplanted mice with induced colitis) and control IL10-/- KO mice. Engraftment, detected at 3 months post-transplant, correlated with markedly improved grading in colon histology (grade-1 or -0) and weight gain, as well as with decreased rectal prolapses. In vitro pre-differentiated ES cells migrated and homed exclusively into the colon, small intestine, and the liver, engrafted for long term, reduced inflammation and tissue damage, and restored immune balance. These findings suggest that pre-differentiated ES cells may become alternative source of stem cell therapy for CD with dual functions i.e. regenerating damaged epithelium and restoring immune imbalance occurring in this disease.