Pediatric short-bowel syndrome: the cost of comprehensive care

Novel neonatal piglet models of surgical short bowel syndrome with intestinal failure

OBJECTIVES

Short bowel syndrome occurring after surgery for acquired or congenital intestinal abnormalities causes considerable neonatal morbidity and mortality. Animal models are a valuable research tool for this problem; however, few successful neonatal models have been developed and most do not include distal intestinal resection as seen commonly in human babies. We report novel piglet models addressing these gaps.

SUBJECTS AND METHODS

Neonatal piglets (1-6 days) underwent venous and gastric catheter insertion and 75% intestinal resection. Group 1 (n = 6) had midintestinal resection with jejunoileal anastomosis; group 2 (n = 5) had distal intestinal resection with jejunocolic anastomosis; group 3 (n = 5) were sham controls; and group 4 (n = 5) were sow reared. Postoperatively, groups 1 to 3 piglets commenced parenteral nutrition (PN), and enteral nutrition was introduced and advanced using a standard regimen. Data collection included days on PN, weight gain, fat absorption, small intestine lengthening, and bowel/liver histology.

RESULTS

Group 2 piglets had more days on PN (P = 0.008), less weight gain (P = 0.027), and greater malabsorption (P = 0.012). They did not show small intestine lengthening and had more cholestatic liver disease. Group 1 piglets had histological evident intestinal adaptation and 1.5-fold intestinal lengthening (P = 0.001).

CONCLUSIONS

These novel piglet models of short bowel syndrome are the first to represent the full clinical spectrum of intestinal failure as observed in human neonates. By considering the impact of different short bowel anatomy on potential for adaptation and growth, these animal models are a significant advance. They permit evaluation of new therapies to promote intestinal adaptation and reduce complications, such as cholestasis.

Elements of successful intestinal rehabilitation

PURPOSE

The optimal therapy for intestinal failure (IF) is unknown. The results of a systematic, protocol-driven management strategy by a multidisciplinary team are described.

METHODS

Intestinal failure was defined as bowel length of less than 40 cm or parenteral nutrition (PN) for more than 42 days. A multidisciplinary team and protocol to prevent PN-associated liver disease (PNALD) were instituted in 2006. Data were gathered prospectively with consent and ethics board approval.

RESULTS

From 1998 to 2006, 33 patients were treated (historical cohort) with an overall survival of 72%. Rotating prophylactic antibiotics for bacterial overgrowth were given to 27% of patients; 6% had lipid-sparing PN, and none received fish oil-based lipids. Median time to intestinal rehabilitation was 7 ± 3.1 months, and 27% of patients who developed PNALD died. From 2006 to 2009, 31 patients were treated. Seventy-seven percent received PAB; 60%, lipid-sparing PN; and 47%, parenteral fish oil emulsion. Eighty-seven percent weaned from PN at 3.9 ± 3.8 months, and no patients developed PNALD with 100% survival. Novel lipid therapies were associated with changes in essential fatty acid profile and one case of clinical essential fatty acid deficiency.

CONCLUSION

The institution of a multidisciplinary team and a protocol-driven strategy to prevent PNALD improves survival in IF. Further studies are recommended.

The feasibility of using an endoluminal device for intestinal lengthening

PURPOSE

Prior studies demonstrating the ability to lengthen intestinal segments with mechanical force required devices with extracorporeal components. The feasibility of using a completely implantable device for in vivo intestinal lengthening was evaluated in this study.

METHODS

Biocompatible Nitinol springs capable of 5-fold expansions were compressed using absorbable sutures and were implanted into isolated segments of proximal jejunum in rats. Springs compressed with nonabsorbable sutures served as controls. The animals were observed with serial abdominal x-rays until the springs became fully expanded. Intestinal segments were then retrieved for histologic analysis. Two-tailed and paired Student's t tests were used for statistical analysis.

RESULTS

Intestinal segments were successfully lengthened in the experimental group from 1.3 +/- 0.3 cm to 4.4 +/- 0.5 cm (P < .001). Maximum spring length was achieved on postoperative day 36 (range, 16-50 days). In the control group, there was also an increase in intestinal lengths, from 1.6 +/- 0.04 cm to 2.9 +/- 0.4 cm (P < .001) (Fig. 4). In percentages, a 250% increase in length was observed in the experimental group vs an 85% increase in the control group (P < .001). Microscopic evaluation of both control and experimental segments revealed gross preservation of intestinal architecture; however, muscular layer hypertrophy and villous atrophy were noted.

CONCLUSIONS

Continuous mechanical force with an implantable spring successfully lengthened isolated segments of small bowel in an animal model. Although similar results have been demonstrated using other devices, the current device is totally implantable and may be deployed endoscopically.

The rate of bloodstream infection is high in infants with short bowel syndrome: relationship with small bowel bacterial overgrowth, enteral feeding, and inflammatory and immune responses

OBJECTIVE

This pilot study in parenteral nutrition-dependent infants with short bowel syndrome (SBS) evaluated the impact of feeding route and intestinal permeability on bloodstream infection (BSI), small bowel bacterial overgrowth (SBBO), and systemic immune responses, as well as fecal calprotectin as a biomarker for SBBO.

STUDY DESIGN

Ten infants (ages 4.2-15.4 months) with SBS caused by necrotizing enterocolitis were evaluated. Nutritional assessment, breath hydrogen testing, intestinal permeability, fecal calprotectin, serum flagellin- and lipopolysaccharide-specific antibody titers, and proinflammatory cytokine concentrations (tumor necrosis factor-alpha [TNF-alpha], interleukin-1 beta, -6, and -8) were performed at baseline and at 60 and 120 days. Healthy, age-matched control subjects (n = 5) were recruited.

RESULTS

BSI incidence was high (80%), and SBBO was common (50%). SBBO increased the odds for BSI (>7-fold; P = .009). Calprotectin levels were higher in children with SBS and SBBO versus those without SBBO and healthy control subjects (P < .05). Serum TNF-alpha, was elevated at baseline versus controls. Serum TNF-alpha and interleukin-1 beta, -6, and -8 levels diminished with increased enteral nutrition. Anti-flagellin and anti-lipopolysaccharide immunoglobulin G levels in children with SBS were lower versus control subjects and rose over time.

CONCLUSION

In children with SBS, SBBO increases the risk for BSI, and systemic proinflammatory response decreases with increasing enteral feeding and weaning parenteral nutrition.

The influence of nutrients, biliary-pancreatic secretions, and systemic trophic hormones on intestinal adaptation in a Roux-en-Y bypass model

PURPOSE

The signals that govern the upregulation of nutrient absorption (adaptation) after intestinal resection are not well understood. A Gastric Roux-en-Y bypass (GRYB) model was used to isolate the relative contributions of direct mucosal stimulation by nutrients, biliary-pancreatic secretions, and systemic enteric hormones on intestinal adaptation in short bowel syndrome.

METHODS

Male rats (350-400 g; n = 8/group) underwent sham or GRYB with pair feeding and were observed for 14 days. Weight and serum hormonal levels (glucagon-like peptide-2 [GLP-2], PYY) were quantified. Adaptation was assessed by intestinal morphology and crypt cell kinetics in each intestinal limb of the bypass and the equivalent points in the sham intestine. Mucosal growth factors and expression of transporter proteins were measured in each limb of the model.

RESULTS

The GRYB animals lost weight compared to controls and exhibited significant adaptive changes with increased bowel width, villus height, crypt depth, and proliferation indices in the alimentary and common intestinal limbs. Although the biliary limb did not adapt at the mucosa, it did show an increased bowel width and crypt cell proliferation rate. The bypass animals had elevated levels of systemic PYY and GLP-2. At the mucosal level, insulin-like growth factor-1 (IGF-1) and basic fibroblast growth factor (bFGF) increased in all limbs of the bypass animals, whereas keratinocyte growth factor (KGF) and epidermal growth factor (EGF) had variable responses. The expression of the passive transporter of glucose, GLUT-2, expression was increased, whereas GLUT-5 was unchanged in all limbs of the bypass groups. Expression of the active mucosal transporter of glucose, SGLT-1 was decreased in the alimentary limb.

CONCLUSIONS

Adaptation occurred maximally in intestinal segments stimulated by nutrients. Partial adaptation in the biliary limb may reflect the effects of systemic hormones. Mucosal content of IGF-1, bFGF, and EGF appear to be stimulated by systemic hormones, potentially GLP-2, whereas KGF may be locally regulated. Further studies to examine the relationships between the factors controlling nutrient-induced adaptation are suggested. Direct contact with nutrients appears to be the most potent factor in inducing mucosal adaptation.

Interdisciplinary management of infantile short bowel syndrome: resource consumption, growth, and nutrition

BACKGROUND/PURPOSE

To date, there are hardly any data on the treatment costs of infantile short bowel syndrome (SBS), despite growing interest in evidence-based and cost-effective medicine. Therefore, the aim of the study was to evaluate resource consumption and costs, next to studying nutritional and growth outcomes, in children with SBS who were treated by an interdisciplinary short bowel team.

METHODS

Data were collected for 10 children with infantile SBS (<or=1 year of age) born between 2002 and 2007. Data included demographic and medical data of the first admission and data on resource consumption, growth, and type of nutrition for the total follow-up period. Real economic costs were calculated in Euro (euro) and US dollar ($).

RESULTS

Seven of the 10 patients were discharged with home parenteral nutrition. Total follow-up varied between 9 months and 5.5 years (median, 1.5 years). Six patients could be weaned off parenteral nutrition and 5 patients off enteral tube feeding, resulting in full oral intake. Seven patients had normal growth. Median duration of initial hospital admission was 174 days, and average costs of initial admission amounted to euro166,045 ($218,681). Average total costs were euro269,700 ($355,195), reaching to a maximum of euro455,400 ($599,762). These costs mainly comprised hospital admissions (82%), followed by nutrition (12%), surgical interventions (5%), and outpatient visits (1%).

CONCLUSIONS

This study is among the first to describe resource consumption and costs in infants with SBS, examining real economic costs and extending beyond the initial hospitalization. Treatment of SBS requires considerable resource consumption, especially when patients depend on parenteral nutrition. Because the costs mainly comprise those of hospital admissions, early home parenteral nutrition could contribute to costs reduction. Interdisciplinary teams have the potential to facilitate early home parenteral nutrition and thus may reduce health care costs.

Short bowel syndrome: epidemiology and etiology

Pediatric short bowel syndrome (SBS) is most commonly caused by congenital or acquired conditions of the newborn. SBS is associated with an inability of the bowel to adequately absorb water and nutrients in sufficient quantities to meet caloric, fluid, and electrolyte demands, thus necessitating dependence on parenteral nutrition (PN). It is this dependence on PN, that is responsible for the majority of morbidity and mortality associated with SBS, including central venous catheter infections and PN-induced cholestatic liver dysfunction. There are very few estimates of SBS incidence and mortality in the literature. The epidemiology of SBS is reviewed and the limitations of the published literature are discussed.

The assessment, and glucagon-like peptide-2 modulation, of intestinal absorption and function

The treatment of patients with short bowel syndrome is hampered by a lack of treatment and measurement methods. This article reviews our evolving understanding of the role of glucagon-like peptide 2 (GLP-2) in controlling the adaptive process. The ability of the remnant intestine to produce GLP-2 appears to be predictive of the adaptive process; exogenous GLP-2 may be a therapy to augment adaptation. Strategies for monitoring patients, including conventional means, such as anthropomorphic measurements, plasma levels of specific nutrients, and vitamins and radiological contrast studies are reviewed. Investigational methods, such as nutrient balance studies, plasma citrulline levels, and the absorption of inert sugars (3-0 methyl glucose, mannitol, and lactulose) are discussed with the evidence to support their use.

Growth factors: possible roles for clinical management of the short bowel syndrome

The structural and functional changes during intestinal adaptation are necessary to compensate for the sudden loss of digestive and absorptive capacity after massive intestinal resection. When the adaptive response is inadequate, short bowel syndrome (SBS) ensues and patients are left with the requirement for parenteral nutrition and its associated morbidities. Several hormones have been studied as potential enhancers of the adaptation process. The effects of growth hormone, insulin-like growth factor-1, epidermal growth factor, and glucagon-like peptide 2 on adaptation have been studied extensively in animal models. In addition, growth hormone and glucagon-like peptide 2 have shown promise for the treatment of SBS in clinical trials in human beings. Several lesser studied hormones, including leptin, corticosteroids, thyroxine, testosterone, and estradiol, are also discussed.

Clinical assessment of the child with intestinal failure

The management of the child with intestinal failure is complex, and it is developing into a multispecialty field of its own led by expert teams of both transplant and nontransplant surgeons, gastroenterologists, and dieticians. Patients are at risk for medical, surgical, and nutritional complications that should be anticipated so that they can be prevented or managed appropriately. Catheter associated infections and intestinal failure associated liver diseases are important complications that impact the likelihood of bowel adaptation and long-term survival. The clinical assessment of a pediatric intestinal failure patient should include evaluation of the child within the context of recognized prognostic factors.

Intestinal failure: A new era in clinical management

Only 50 years ago intestinal failure was considered incompatible with life. Since then, developments in parenteral nutrition, and, more recently, small intestinal transplantation, have provided new therapeutic options with the potential to offer long-term survival with a good quality of life. Current medical and surgical strategies are aimed at enhancing intestinal adaptation, improving absorption to achieve nutritional independence, and minimizing the complications of parenteral nutrition therapy. An integrated, multidisciplinary approach to the management of patients with intestinal failure, closely linked to a transplantation program to facilitate early referral, is recognized as a key factor in optimizing patient outcomes.

Nutritional deficiencies in intestinal failure

Intestinal failure (IF) is the ultimate malabsorption state, with multiple causes, requiring long-term therapy with enteral or intravenous fluids and nutrient supplements. The primary goal during management of children with potentially reversible IF is to promote intestinal autonomy while supporting normal growth, nutrient status, and preventing complications from parenteral nutrition therapy. This article presents how an improved understanding of digestive pathophysiology is essential for diagnosis, successful management, and prevention of nutrient deficiencies in children with IF.