Intestinal lengthening and reversed segment in a piglet short bowel syndrome model

Segmental reversal of the distal small intestine in a short bowel syndrome model in piglets showed detrimental effect on weight gain

Background

To investigate the effects of a reversed segment of the distal small intestine to improve weight gain in an experimental short bowel syndrome (SBS) model in piglets.

Methods

Twenty-four piglets underwent resection of 70% of the distal small intestine. In half of the animals a conventional anastomosis was performed, and in the other half, the distal 25 cm of the remnant jejunum was reversed before the intestinal continuity was recreated. Weight was measured daily until day 28, where the animals were euthanized. Glucagon-Like Peptide-2 (GLP-2) and Glucose-dependent Insulinotropic Peptide (GIP) was measured pre- and postoperatively at day 28.

Results

The group with reversal of small intestine had a significant lower weight gain at 5.26 ± 3.39 kg (mean ± SD) compared to the control group with 11.14 ± 3.83 kg (p < 0.05). In the control group greater villus height and crypt depth was found distally, and greater muscular thickness was found proximally in the intervention group. GLP-2 and GIP levels increased significantly in the control group.

Conclusions

Treatment of short bowel syndrome with a reversed jejunal segment of 25 cm had a detrimental effect on the weight gain.

Ileostomy for steroid-resistant acute graft-versus-host disease of the gastrointestinal tract

Steroid-resistant acute graft-versus-host disease (GVHD) of the gastrointestinal tract associates with important morbidity and mortality. While high-dose steroids are the established first-line therapy in GVHD, no second-line therapy is generally accepted. In this analysis of 65 consecutive patients with severe, steroid-resistant, intestinal GVHD (92% stage 4), additional ileostomy surgery significantly reduced overall mortality (hazard ratio 0.54; 95% confidence interval, 0.36-0.81; p = 0.003) compared to conventional GVHD therapy. Median overall survival was 16 months in the ileostomy cohort compared to 4 months in the conventional therapy cohort. In the ileostomy cohort, both infectious- and GVHD-associated mortality were reduced (40% versus 77%). Significantly declined fecal volumes (p = 0.001) after surgery provide evidence of intestinal adaptation following ileostomy. Correlative studies indicated ileostomy-induced immune-modulation with a > 50% decrease of activated T cells (p = 0.04) and an increase in regulatory T cells. The observed alterations of the patients' gut microbiota may also contribute to ileostomy's therapeutic effect. These data show that ileostomy induced significant clinical responses in patients with steroid-resistant GVHD along with a reduction of pro-inflammatory immune cells and changes of the intestinal microbiota. Ileostomy is a treatment option for steroid-resistant acute GVHD of the gastrointestinal tract that needs further validation in a prospective clinical trial.

Autologous intestinal reconstruction surgery

The management of short bowel syndrome has mainly been focused on intestinal rehabilitation as part of multidisciplinary team approach in specialized centers. While some patients go through a process of bowel adaptation that allows them to reach enteral autonomy, others reach a plateau before this and require prolonged parenteral nutrition and/or intestinal transplantation. Various autologous intestinal reconstruction procedures centered on bowel tapering have been described to increase functional intestinal area and help gain enteral autonomy. This review discusses the surgical techniques, advantages, limitations, and general outcomes of each procedure.

Segmental reversal of distal small intestine in short bowel syndrome: a study on the influence on postoperative weight and intestinal topography in piglets

PURPOSE

The objective of the present study was to investigate the effect of segmental reversal of the distal 20 cm of the small intestine in piglets with induced SBS compared to controls with SBS alone. Primary endpoint was postoperative weight change over a period of 1 month. Secondary endpoints were the influence on cell proliferation and mucosal architecture shown by histological analysis.

METHODS

Sixteen piglets underwent a 60% resection of the distal small intestine and were randomized into two groups. Group 1 short bowel syndrome alone (SBS) (n = 8) and group 2 with reversal of a distal small intestinal segment (SBS-RS) (n = 8). Body weight was measured daily and the pigs were euthanized after 1 month. Crypt depths, villus heights and muscle layers thicknesses were measured. For the evaluation of microvilli of the brush border of the epithelium and cell proliferation, immunohistochemical staining with Villin and Ki-67 was performed.

RESULTS

No statistically significant differences were observed concerning weight gain. Mean ± SD weight gain was 2.31 ± 2.85 kg for SBS-RS and 2.03 ± 1.27 kg for SBS (p = 0.8). In the proximal jejunal segment a significant increase in villus heights was found in the SBS group and increase in the thickness of the circular and longitudinal muscle layers in the SBS-RS group. In the distal ileal segment the longitudinal muscle layer thicknesses were increased in the SBS group. Otherwise, no significant changes were found.

CONCLUSION

Reversal of a 20-cm distal segment showed no effect on weight gain, but there were some significant histological changes of unknown clinical significance.

Marked stem/progenitor cell expansion occurs early after murine ileostomy: a new model

BACKGROUND

Improving treatment for short bowel syndrome requires a better understanding of how intestinal adaptation is affected by factors like mechanoluminal stimulation. We hypothesized that in mice, luminal diversion via an ileostomy would drive adaptive changes similar to those seen in human intestine after diversion while offering the opportunity to study the immediate events after resection that precede intestinal adaptation.

MATERIALS AND METHODS

With Institutional Animal Care and Use Committee approval, a distal ileostomy with a long distal Hartman's was created in 9- to 14-week-old C57/B6 mice (n = 8). Control mice only had a midline laparotomy without stoma formation (n = 5). A rim of tissue from the proximal stoma was resected as a historical control for the proximal segment. Postoperatively, mice received a high-protein liquid diet and water ad libitum. On day 3, tissue from both the proximal and distal limbs were collected for histologic and RNA analysis. Morphometric measures, immunofluorescent antigen detection, and RNA expression were compared with Student paired t-tests with a P value < 0.05 considered significant.

RESULTS

At 3 d, survival for mice with an ileostomy was 87% and average weight loss was 12.5% of initial weight compared to 6.05% for control mice. Compared to the distal limb, the proximal limb in mice with an ileostomy demonstrated significantly taller villi with deeper and wider crypts. The proximal limb also had decreased expression of intestinal stem cell markers lgr5, bmi1, sox9, and ascl2. Fewer goblet and enteroendocrine cells per hemivillus were also noted in the proximal limb. In control mice, none of these measures were significant between proximal and distal ileum except for villus height.

CONCLUSIONS

This new murine ileostomy model allows study of intestinal adaptation without intestinal anastomosis, which can be technically challenging and morbid.

Creation of an animal model for long gap pure esophageal atresia

INTRODUCTION

Long gap pure esophageal atresia (LGPEA) is a congenital disorder in which the esophagus is in discontinuity, and the proximal and distal ends cannot be anastomosed in a primary fashion. No animal model for pure esophageal atresia exists. Here we describe a survival animal model for LGPEA, which will ultimately serve to test novel devices and techniques to restore continuity.

METHODS

A non-survival study was first conducted in six rabbits to refine a protocol for the survival model. An open gastrostomy tube was placed, followed by a partial esophagectomy. Next, a survival study was performed with seven rabbits in which the same procedures were performed. Finally, the procedure was optimized in domestic swine.

RESULTS

Despite developing the techniques and gaining valuable information in the non-survival study, none of the rabbits in the survival portion of the study lived beyond post-operative day four. Due to this complication with the rabbit, the LGPEA model was attempted in a porcine model. The pig survived to post-operative day ten, and was healthy enough to be used for further study.

CONCLUSION

A porcine model of long gap pure esophageal atresia was developed which is effective and feasible to be used for testing new methods of treatment of LGPEA.