Nutritional Management of Short Bowel Syndrome

Short bowel syndrome (SBS) of infancy is a cause of prolonged morbidity with intolerance to enteral feeding, specialized nutritional needs, and partial/total dependence on parenteral nutrition. These infants can benefit from individualized nutritional strategies to support and enhance the process of intestinal adaptation. Early introduction of enteral feeds during the period of intestinal adaptation is crucial, even though the enteral feedings may need to be supplemented with an effective, safe, and nutritionally adequate parenteral nutritional regimen. Newer generation intravenous lipid emulsions can be effective in preventing and treating intestinal failure-associated liver disease. Prevention of infection(s), pharmaceutical interventions to enhance bowel motility and prevent/mitigate bacteria overgrowth, and specialized multidisciplinary care to minimize the injury to other organs such as the liver, kidneys, and the brain can assist in nutritional rehabilitation and lower the morbidity in SBS.

Short Bowel Syndrome and Dysmotility

Due to recent advances, the mortality due to short bowel syndrome (SBS) has significantly decreased, but the morbidities are still high. Morbidities arising specifically due to dysmotility in SBS include feeding intolerance, prolonged dependence on parenteral nutrition, and associated complications such as intestinal failure associated liver disease, and bloodstream infections. The understanding of the pathogenesis of dysmotility in SBS has improved vastly. However, the tools to diagnose dysmotility in SBS in infants are restrictive, and the medical therapies to treat dysmotility are limited. Surgical techniques available for the treatment after failure of conservative management of dysmotility offer hope but carry their associated risks. The evidence to support either the medical therapies or the surgical techniques to treat dysmotility in SBS in children is scarce and weak. Development of newer therapies and efforts to build evidence to support currently available treatments in treating dysmotility in SBS is needed.

Self-expanding intestinal expansion sleeves (IES) for short gut syndrome

PURPOSE

Many disease processes (necrotizing enterocolitis, caustic esophageal injury, malrotation with volvulus), can result in short-gut syndrome (SGS), where remnant intestinal segments may dilate axially, but rarely elongate longitudinally. Here we mechanically characterize a novel model of a self-expanding mesh prototype intestinal expanding sleeve (IES) for use in SGS.

METHODS

Gut lengthening was achieved using a proprietary cylindrical layered polyethylene terephthalate IES device with helicoid trusses with isometric ends. The IES is pre-contracted by diametric expansion, deployed into the gut and anchored with bioabsorbable sutures. IES expansion to its equilibrium dimension maintained longitudinal gut tension, which may permit remodeling, increased absorptive surface area while preserving vascular and nervous supplies. We performed mechanical testing to obtain the effective force-displacement characterization achieved on these prototypes and evaluated minimal numbers of sutures needed for its anchoring. Furthermore, we deployed these devices in small and large intestines of New Zealand White rabbits, measured IES length-tension relationships and measured post-implant gut expansion ex vivo. Histology of the gut before and after implantation was also evaluated.

RESULTS

Longitudinal tension using IES did not result in suture failure. Maximum IES suture mechanical loading was tested using 4-6 sutures; we found similar failure loads of 2.95 ± 0.64, 4 ± 1.9 and 3.16 ± 0.24 Newtons for 4, 6 and 8 sutures, respectively (n = 3, n.s). Pre-contracted IES tubes were deployed at 67 ± 4% of initial length (i.l.); in the large bowel these expanded significantly to 81.5 ± 3.7% of i.l. (p = 0.014, n = 4). In the small bowel, pre-contracted IES were 61 ± 3.8% of i.l.; these expanded significantly to 82.7 ± 7.4% of i.l. (p = 0.0009, n = 6). This resulted in an immediate 24 ± 7.8% and 36.2 ± 11% increase in gut length when deployed in large and small bowels, respectively, with maintained longitudinal tension. Maintained IES induced tension produced gut wall thinning; gut histopathological evaluation is currently under evaluation.

CONCLUSION

IES is a versatile platform for gaining length in SGS, which may be simply deployed via feeding tubes. Our results need further validation for biocompatibility and mechanical characterization to optimize use in gut expansion.

Small Bowel Resection Increases Paracellular Gut Barrier Permeability via Alterations of Tight Junction Complexes Mediated by Intestinal TLR4

BACKGROUND

Short bowel syndrome resulting from small bowel resection (SBR) is associated with significant morbidity and mortality. Many adverse sequelae including steatohepatitis and bacterial overgrowth are thought to be related to increased bacterial translocation, suggesting alterations in gut permeability. We hypothesized that after intestinal resection, the intestinal barrier is altered via toll-like receptor 4 (TLR4) signaling at the intestinal level.

METHODS

B6 and intestinal-specific TLR4 knockout (iTLR4 KO) mice underwent 50% SBR or sham operation. Transcellular permeability was evaluated by measuring goblet cell associated antigen passages via two-photon microscopy. Fluorimetry and electron microscopy evaluation of tight junctions (TJ) were used to assess paracellular permeability. In parallel experiments, single-cell RNA sequencing measured expression of intestinal integral TJ proteins. Western blot and immunohistochemistry confirmed the results of the single-cell RNA sequencing.

RESULTS

There were similar number of goblet cell associated antigen passages after both SBR and sham operation (4.5 versus 5.0, P > 0.05). Fluorescein isothiocyanate-dextran uptake into the serum after massive SBR was significantly increased compared with sham mice (2.13 ± 0.39 ng/μL versus 1.62 ± 0.23 ng/μL, P < 0.001). SBR mice demonstrated obscured TJ complexes on electron microscopy. Single-cell RNA sequencing revealed a decrease in TJ protein occludin (21%) after SBR (P < 0.05), confirmed with immunostaining and western blot analysis. The KO of iTLR4 mitigated the alterations in permeability after SBR.

CONCLUSIONS

Permeability after SBR is increased via changes at the paracellular level. However, these alterations were prevented in iTLR4 mice. These findings suggest potential protein targets for restoring the intestinal barrier and obviating the adverse sequelae of short bowel syndrome.

Long-term surgical outcomes of apple-peel atresia

PURPOSE

The purpose of this study was to investigate (i) postoperative course of apple-peel atresia (APA), (ii) long-term follow-up of APA children, and (iii) risk factors for poor prognosis.

METHODS

We conducted a retrospective review of 39 APA neonates treated at our institution between 2008 and 2017. Patient characteristics, operative details, postoperative course, long-term outcomes, and prognostic factors were analyzed.

RESULTS

Of the 39 APA neonates, 30 (76.9%) were born preterm, and 20 (51.3%) were diagnosed prenatally. All patients underwent primary anastomosis within the first week after birth: 10 laparoscopic-assisted (25.6%) and 29 open (74.4%). Postoperative complications occurred in 28 patients (71.8%), of which 20 (71.4%) developed cholestasis. Survival at hospital discharge was 94.9%. Median parenteral nutrition period was 59 days. Reoperation was required in 7 children (17.9%) owing to anastomotic obstruction (n = 3) and adhesive intestinal obstruction (n = 4). 32 children (82.1%) were followed up for an average of 5.7 years, of which 23 children (71.9%) showed normal growth and development. APA patients with low birth weight and associated anomalies had significantly worse outcomes.

CONCLUSION

Most of the patients with apple-peel atresia have excellent long-term outcomes, though initial postoperative complications are common. Low birth weight and the presence of associated anomalies are independent prognostic factors in APA.

TYPE OF STUDY

Prognosis study (case series).

LEVEL OF EVIDENCE

Level IV.

Closing gastroschisis: The good, the bad, and the not-so ugly

PURPOSE

The diagnosis of "closing" or "closed gastroschisis" is made when bowel is incarcerated within a closed or nearly closed ring of fascia, usually with associated bowel atresia. It has been described as having a high morbidity and mortality.

METHODS

A retrospective review of closing gastroschisis cases (n = 53) at six children's hospitals between 2000 and 2016 was completed after IRB approval.

RESULTS

A new classification system for this disease was developed to represent the spectrum of the disease: Type A (15%): ischemic bowel that is constricted at the ring but without atresia; Type B (51%): intestinal atresia with a mass of ischemic, but viable, external bowel (owing to constriction at the ring); Type C (26%): closing ring with nonviable external bowel +/- atresia; and Type D (8%): completely closed defect with either a nubbin of exposed tissue or no external bowel. Overall, 87% of infants survived, and long-term data are provided for each type.

CONCLUSIONS

This new classification system better captures the spectrum of disease and describes the expected long-term results for counseling. Unless the external bowel in a closing gastroschisis is clearly necrotic, it should be reduced and evaluated later. Survival was found to be much better than previously reported.

TYPE OF STUDY

Retrospective case series with no comparison group.

LEVEL OF EVIDENCE

Level IV.

Mucous fistula refeeding decreases parenteral nutrition exposure in postsurgical premature neonates

BACKGROUND/PURPOSE

Premature neonates can develop intraabdominal conditions requiring emergent bowel resection and enterostomy. Parenteral nutrition (PN) is often required, but results in cholestasis. Mucous fistula refeeding allows for functional restoration of continuity. We sought to determine the effect of refeeding on nutrition intake, PN dependence, and PN associated hepatotoxicity while evaluating the safety of this practice.

METHODS

A retrospective review of neonates who underwent bowel resection and small bowel enterostomy with or without mucous fistula over 2years was undertaken. Patients who underwent mucous fistula refeeding (RF) were compared to those who did not (OST). Primary outcomes included days from surgery to discontinuation of PN and goal enteral feeds, and total days on PN. Secondary outcomes were related to PN hepatotoxicity.

RESULTS

Thirteen RF and eleven OST were identified. There were no significant differences among markers of critical illness (p>0.20). In the interoperative period, RF patients reached goal enteral feeds earlier than OST patients (median 28 versus 43days; p=0.03) and were able to have PN discontinued earlier (median 25 versus 41days; p=0.04). Following anastomosis, the magnitude of effect was more pronounced, with RF patients reaching goal enteral feeds earlier than OST patients (median 7.5 versus 20days; p≤0.001) and having PN discontinued sooner (30.5 versus 48days; p=0.001).

CONCLUSIONS

RF neonates reached goal feeds and were able to be weaned from PN sooner than OST patients. A prospective multicenter trial of refeeding is needed to define the benefits and potential side effects of refeeding in a larger patient population in varied care environments.