Intestinal Epithelial Stem Cells: Distinct Behavior After Surgical Injury and Teduglutide Administration

Impaired intestinal FXR signaling is involved in aberrant stem cell function leading to intestinal failure-associated liver disease in pediatric patients with short bowel syndrome

Intestinal failure-associated liver disease (IFALD) is a serious complication of long-term parenteral nutrition in patients with short bowel syndrome (SBS), and is the main cause of death in SBS patients. Prevention of IFALD is one of the major challenges in the treatment of SBS. Impairment of intestinal barrier function is a key factor in triggering IFALD, therefore promoting intestinal repair is particularly important. Intestinal repair mainly relies on the function of intestinal stem cells (ISC), which require robust mitochondrial fatty acid oxidation (FAO) for self-renewal. Herein, we report that aberrant LGR5+ ISC function in IFALD may be attributed to impaired farnesoid X receptor (FXR) signaling, a transcriptional factor activated by steroids and bile acids. In both surgical biopsies and patient-derived organoids (PDOs), SBS patients with IFALD represented lower population of LGR5+ cells and decreased FXR expression. Moreover, treatment with T-βMCA in PDOs (an antagonist for FXR) dose-dependently reduced the population of LGR5+ cells and the proliferation rate of enterocytes, concomitant with decreased key genes involved in FAO including CPT1a. Interestingly, however, treatment with Tropifexor in PDOs (an agonist for FXR) only enhanced FAO capacity, without improvement in ISC function and enterocyte proliferation. In conclusion, these findings suggested that impaired FXR may accelerate the depletion of LGR5 + ISC population through disrupted FAO processes, which may serve as a new potential target of preventive interventions against IFALD for SBS patients.

Lactobacillus reuteri maintains intestinal epithelial regeneration and repairs damaged intestinal mucosa

Little is known about the regulatory effect of microbiota on the proliferation and regeneration of ISCs. Here, we found that L. reuteri stimulated the proliferation of intestinal epithelia by increasing the expression of R-spondins and thus activating the Wnt/β-catenin pathway. The proliferation-stimulating effect of Lactobacillus on repair is further enhanced under TNF -induced intestinal mucosal damage, and the number of Lgr5⁺ cells is maintained. Moreover, compared to the effects of C. rodentium on the induction of intestinal inflammation and crypt hyperplasia in mice, L. reuteri protected the intestinal mucosal barrier integrity by moderately modulating the Wnt/β-catenin signaling pathway to avoid overactivation. L. reuteri had the ability to maintain the number of Lgr5⁺ cells and stimulate intestinal epithelial proliferation to repair epithelial damage and reduce proinflammatory cytokine secretion in the intestine and the LPS concentration in serum. Moreover, activation of the Wnt/β-catenin pathway also induced differentiation toward Paneth cells and increased antimicrobial peptide expression to inhibit C. rodentium colonization. The protective effect of Lactobacillus against C. rodentium infection disappeared upon application of the Wnt antagonist Wnt-C59 in both mice and intestinal organoids. This study demonstrates that Lactobacillus is effective at maintaining intestinal epithelial regeneration and homeostasis as well as at repairing intestinal damage after pathological injury and is thus a promising alternative therapeutic method for intestinal inflammation.

Teduglutide-induced stem cell function in intestinal repair

Malabsorption is a major and common clinical characteristics of short bowel syndrome (SBS) and inflammatory bowel diseases (IBD). Traditional treatment opportunities have focused on decreasing malabsorptive losses via dietary modifications and antisecretory/antidiarrheal agents. However, novel therapeutic modalities aim to enhance the absorptive capacity of the residual bowel by the administration of different intestinal growth factors including teduglutide. In a current study the existence of two distinct functional putative epithelial stem cell subpopulations (i.e. Lgr5+/Bmi1- and Lgr5-/Bmi1+) have been described in a rat model of ileal resection and anastomosis. The described epithelial stem cell subpopulations displayed distinct behaviour after surgical injury and teduglutide administration. Though teduglutide was found to be clinically effective, we must keep in mind that growth factors theoretically may provoke adenoma development and subsequent malignant transformation. The present results give us a better insight into the role of stem cell modulation in intestinal repair. Based on these results new perioperative adjuvant pharmacological approaches may be developed for SBS and IBD patients to reduce the clinical symptoms and complications of associated malabsorption.