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Short bowel mucosal morphology, proliferation and inflammation at first and repeat STEP procedures
Annika Mutanen1, Meredith Barrett2, Yongjia Feng2
1Section of Pediatric Surgery, Pediatric Liver and Gut Research Group, Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
Insights
Repeat surgery for short bowel syndrome (SBS) after serial transverse enteroplasty (STEP) may be linked to persistent inflammation and lack of mucosal growth. These factors, especially after ileocecal valve removal, can hinder intestinal function.
Area of Science:
- Pediatric surgery
- Gastroenterology
- Intestinal adaptation
Background:
- Serial transverse enteroplasty (STEP) is used to improve function in children with short bowel syndrome (SBS).
- A significant number of patients require repeat surgeries after initial STEP.
- Understanding reasons for repeat surgery is crucial for improving outcomes.
Purpose of the Study:
- To compare small intestinal mucosal characteristics between initial and repeat STEP procedures in children with SBS.
- To identify factors contributing to unsuccessful STEP and the need for reoperation.
Main Methods:
- Retrospective analysis of 15 children with SBS who underwent initial and repeat STEP procedures.
- Histological examination of small bowel samples for mucosal morphology, inflammation, and muscular thickness.
- Immunohistochemical analysis of mucosal proliferation (MIB1) and apoptosis (Tunel).
Main Results:
- Repeat STEP showed less significant increases in small bowel length and enteral caloric intake compared to initial STEP.
- Abnormal mucosal inflammation was common in both initial (69%) and repeat (86%) surgeries.
- No significant differences in villus height, crypt depth, proliferation, apoptosis, or muscle thickness were found between initial and repeat STEP. Patients needing repeat STEP were younger and had fewer apoptotic crypt cells initially. Absence of the ileocecal valve correlated with increased inflammation and reduced crypt cell proliferation.
Conclusions:
- No adaptive mucosal hyperplasia or muscular changes were observed between first and repeat STEP.
- Persistent inflammation and inadequate mucosal growth may contribute to ongoing bowel dysfunction in SBS patients requiring repeat STEP.
- Ileocecal valve removal appears to exacerbate these issues, highlighting the need for targeted interventions.
Background:
Although serial transverse enteroplasty (STEP) improves function of dilated short bowel, a significant proportion of patients require repeat surgery. To address underlying reasons for unsuccessful STEP, we compared small intestinal mucosal characteristics between initial and repeat STEP procedures in children with short bowel syndrome (SBS).
Methods:
Fifteen SBS children, who underwent 13 first and 7 repeat STEP procedures with full thickness small bowel samples at median age 1.5 years (IQR 0.7-3.7) were included. The specimens were analyzed histologically for mucosal morphology, inflammation and muscular thickness. Mucosal proliferation and apoptosis was analyzed with MIB1 and Tunel immunohistochemistry.
Results:
Median small bowel length increased 42% by initial STEP and 13% by repeat STEP (p=0.05), while enteral caloric intake increased from 6% to 36% (p=0.07) during 14 (12-42) months between the procedures. Abnormal mucosal inflammation was frequently observed both at initial (69%) and additional STEP (86%, p=0.52) surgery. Villus height, crypt depth, enterocyte proliferation and apoptosis as well as muscular thickness were comparable at first and repeat STEP (p>0.05 for all). Patients, who required repeat STEP tended to be younger (p=0.057) with less apoptotic crypt cells (p=0.031) at first STEP. Absence of ileocecal valve associated with increased intraepithelial leukocyte count and reduced crypt cell proliferation index (p<0.05 for both).
Conclusions:
No adaptive mucosal hyperplasia or muscular alterations occurred between first and repeat STEP. Persistent inflammation and lacking mucosal growth may contribute to continuing bowel dysfunction in SBS children, who require repeat STEP procedure, especially after removal of the ileocecal valve.
Level Of Evidence:
Level IV, retrospective study.
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