Growth After Intestinal Transplant in Children

Nutrition support considerations in pediatric small bowel transplantation

Enteral autonomy is the primary goal of intestinal failure therapy. Intestinal transplantation (ITx) is an option when enteral autonomy cannot be achieved and management complications become life-threatening. The purpose of this review is to summarize existing medical literature related to nutrition requirements, nutrition status, and nutrition support after pediatric ITx. Achieving or maintaining adequate growth after intestinal transplant in children can be challenging because of episodes of rejection that require the use of corticosteroids, occurrences of infection that require a reduction or discontinuation of enteral or parenteral support, and fat malabsorption caused by impaired lymphatic circulation. Nutrient requirements should be assessed and modified regularly based on nutrition status, growth, ventilatory status, wound healing, and the presence of complications. Parenteral nutrition (PN) should be initiated as a continuous infusion early postoperatively. Enteral support should be initiated after evidence of graft bowel function and in the absence of clinical complications. Foods high in simple carbohydrates should be limited, as consumption may result in osmotic diarrhea. Short-term use of a fat-free diet followed by a low-fat diet may reduce the risk of the development of chylous ascites. Micronutrient deficiencies and food allergies are common occurrences after pediatric ITx. Enteral/oral vitamin and mineral supplementation may be required after PN is weaned. Nutrition management of children after ITx can be challenging for all members of the healthcare team. Anthropometric parameters and micronutrient status should be monitored regularly so that interventions to promote growth and prevent or reverse nutrient deficiencies can be implemented promptly.

Overview of Physical, Neurocognitive, and Psychosocial Outcomes in Pediatric Intestinal Failure and Transplantation

PURPOSE OF REVIEW

Intestinal failure and transplantation may significantly impact physical, neurocognitive, and psychosocial development in pediatric patients. Currently, there is a paucity of literature on the effects of intestinal failure and transplantation on these aspects of development. This article will review the current literature and discuss the short and long-term impacts as well as interventions to improve clinical outcomes in children with intestinal failure or those undergoing transplantation.

RECENT FINDINGS

Psychological disorders, neurodevelopmental delay, and social maladaptation are frequently encountered in this patient population. While the main focus is often on medical management, equal emphasis should be placed on other aspects of development such as increasing social support and improving school performance. The transition to adulthood also presents many obstacles for patients and healthcare providers should anticipate challenges such as childbirth, employment, and raising a family. The pre-operative, perioperative, and post-operative periods all represent opportunities for medical intervention. Frequent monitoring of physical, psychosocial, and neurocognitive status helps to improve clinical outcomes and long-term quality of life. Future research should emphasize continued development of multidisciplinary programs and specialized services to help address the physical and psychosocial needs of children with intestinal failure as well as transplant recipients.

Intestinal transplantation: current improvements and perspectives

PURPOSE OF REVIEW

This review summarizes the most recent relevant knowledge in clinical practice in the field of intestinal transplantation.

RECENT FINDINGS

Three important factors that have allowed improving results during the last few years are reviewed here. The first relates to the development of a different approach to tackle the underlying cause of intestinal failure and to the patient's characteristics in terms of liver function, age, and body size. The second involves immune modulation and especially the immunosuppressive regimen at induction. The third refers to posttransplantation monitoring, in particular the diagnosis and treatment of intestinal graft rejection and lymphoproliferative disorders. Patient status and referral for intestinal transplantation remain debated. The Intestinal Transplant Registry and a report from an individual program have demonstrated the relationship between a patient's pretransplant status and outcome. Candidacy for intestinal transplantation was analysed in a European survey of home parenteral nutrition patients. Early referral and listing are important for successful outcomes after intestinal grafting.

SUMMARY

Patient management should include therapies adapted to each stage of intestinal failure based on a multidisciplinary approach in centers involving surgery, gastroenterology, parenteral nutrition expertise, home parenteral nutrition programs, and liver-intestinal transplantation experience. Timing for referral of patients in specialized centers remains a crucial issue.

Long-term outcomes of living-related small intestinal transplantation in children: A single-center experience

Pediatric patients with irreversible intestinal failure present a significant challenge to meet the nutritional needs that promote growth. From 2002 to 2013, 13 living-related small intestinal transplantations were performed in 10 children, with a median age of 18 months. Grafts included isolated living-related intestinal transplantation (n=7), and living-related liver and small intestine (n=6). The immunosuppression protocol consisted of induction with thymoglobulin and maintenance therapy with tacrolimus and steroids. Seven of 10 children are currently alive with a functioning graft and good quality of life. Six of the seven children who are alive have a follow-up longer than 10 years. The average time to initiation of oral diet was 32 days (range, 13-202 days). The median day for ileostomy takedown was 77 (range, 18-224 days). Seven children are on an oral diet, and one of them is on supplements at night through a g-tube. We observed an improvement in growth during the first 3 years post-transplant and progressive weight gain throughout the first year post-transplantation. Growth catch-up and weight gain plateaued after these time periods. We concluded that living donor intestinal transplantation potentially offers a feasible, alternative strategy for long-term treatment of irreversible intestinal failure in children.

Energy expenditure and growth failure after intestinal transplantation: A case report

We present a 12-yr-old boy who received a combined liver-pancreas small bowel transplantation at the age of two. The post-operative period was complicated by wound closure problems resulting in a large asymptomatic abdominal wall defect. Further follow-up was uneventful, with the exception of new onset growth failure not explained by extensive routine investigations. An indirect calorimetry was performed. The resting energy expenditure (REE) was significantly increased (126% of predicted), demanding a daily caloric intake of 123 kcal/kg body weight (normal for age: 80 kcal/kg). In the absence of classic reasons for increased REE, a thermal camera revealed increased dermal heat loss at the abdominal wall defect (estimated surplus in energy loss of at least 29 kcal/day: 10.4% of the elevated REE). In addition, we found lower total lung capacity due to impaired abdominal breathing. In the exploration of growth failure in children after (ITx), increased REE must be taken into account. Indirect calorimetry can serve as a valuable diagnostic tool for evaluating individual energy requirements and nutritional support. In this child, exaggerated heat loss through an aberrant abdominal wall could be a potential important contributor to the patient's increased energy requirements.

Neurologic aspects of multiple organ transplantation

Complex multiorgan failure may require simultaneous transplantation of several organs, including heart-lung, kidney-pancreas, or multivisceral transplantation. Solid organ transplantation can also be combined with hematopoietic stem cell transplantation to modulate immunologic response to a solid organ allograft. Combined multiorgan transplantation may offer a lower rate of allograft rejection and lower immunosuppression needs. In recent years, intestinal and multivisceral transplantations became viable as a rescue treatment for patients with irreversible intestinal failure who can no longer tolerate total parenteral nutrition with 70% survival after 5 years which is comparable to other types of solid organ allografts. Post-transplant neurologic complications were reported in up to 86% of allograft recipients and greatly overlap in intestinal and multivisceral allograft recipients, without a significant effect on the outcome of transplantation. Other common organ combinations in multiorgan transplantation include kidney-pancreas, which is mostly used for patients with renal failure and uncontrolled diabetes, and heart-lung for patients with congenital heart disease and idiopathic pulmonary arterial hypertension. Kidney-pancreas transplantation frequently results in an improvement of diabetic complications, including diabetic neuropathy. Heart-lung allograft recipients have very similar clinical course and spectrum of neurologic complications to lung transplant recipients. At this time there are no reports of an increased risk of graft-versus-host disease with combined transplantation of solid organ allograft and hematopoietic stem cells. Chronic immunosuppression and complex toxic-metabolic disturbances after multiorgan transplantation create a permissive environment for development of a wide spectrum of neurologic complications which largely resemble complications after transplantations of individual components of complex multiorgan allografts.

Intestinal absorption rate in children after small intestinal transplantation

BACKGROUND

Small bowel transplantation has now become a recognized treatment of irreversible, permanent, and subtotal intestinal failure.

OBJECTIVE

The aim of this study was to assess intestinal absorption at the time of weaning from parenteral nutrition in a series of children after intestinal transplantation.

DESIGN

Twenty-four children (age range: 14-115 mo) received intestinal transplantation, together with the liver in 6 children and the colon in 16 children. Parenteral nutrition was slowly tapered while increasing enteral tube feeding. The absorption rate was measured from a 3-d stool balance analysis performed a few days after the child had weaned from parenteral nutrition to exclusive enteral tube feeding. Results were analyzed according to the resting energy expenditure (REE; Schofield formula).

RESULTS

All children were weaned from parenteral nutrition between 31 and 85 d posttransplantation. Median intakes were as follows: energy, 107 kcal · kg(-1) · d(-1) (range: 79-168 kcal · kg(-1) · d(-1)); lipids, 39 kcal · kg(-1) · d(-1) (range: 20-70 kcal · kg(-1) · d(-1)); and nitrogen, 17 kcal · kg(-1) · d(-1) (range: 11-27 kcal · kg(-1) · d(-1)). Median daily stool output was 998 mL/d (range: 220-2025 mL/d). Median absorption rates were 88% (range: 75-96%) for energy, 82% (range: 55-98%) for lipids, and 77% (range: 61-88%) for nitrogen. The ratios for ingested energy to REE and absorbed energy to REE were 2.2 (range: 1.6-3.6) and 1.8 (range: 1.3-3.3), respectively.

CONCLUSION

These data indicate a suboptimal intestinal graft absorption capacity with fat malabsorption, which necessitates energy intakes of at least twice the REE.

Growth pre- and postimplementation of a steroid-free induction protocol in a large pediatric intestinal transplant population

OBJECTIVES

Beginning in March 2002, we initiated steroid-free lymphocyte depleting immunosuppression with rabbit anti-human thymocyte globulin (rATG) for all children who received an intestinal transplant (ITx). The purpose of the present study was to determine whether this treatment regimen supported growth. Because steroids were used for rejection episodes only, we hypothesized that improved growth would be observed in steroid-free rATG-treated children.

PATIENTS AND METHODS

Nutrition outcomes in patients who received an ITx between December 1996 and February 2007 were retrospectively reviewed. Nutritional analysis included evaluation of differences in weight and height z scores between transplantation and 2 years post-ITx by the type of immunosuppressant therapy received.

RESULTS

A total of 109 children received an ITx during the evaluation period. Of these, 29 received a transplant before March 2002 and received an induction regimen that included anti-T-cell immunosuppressant, tacrolimus (TAC), with prednisone (steroid). The remaining 80 children received an induction regimen of rATG and TAC without steroids (steroid-free). Steroid-free children met their full nutritional requirements enterally or orally in a median of 2 months, whereas children treated with the steroid regimen reached nutritional autonomy 7 months after transplant (P < 0.001). A positive trend in z score values over time for height was observed in 48% of steroid-free patients versus 44% in the steroid regimen. The change in mean z score for linear growth over time was most positive (0.55) in the steroid-free group and <120 days of steroids during the follow-up period with 62% of patients in this group observed to have positive growth over time.

CONCLUSIONS

Nutritional autonomy was achieved rapidly, and positive growth was observed in the majority of patients with ITx who received steroid-free immunosuppression with rATG.

Catch-up and targeted growth following variable duration protein restriction: effects on bone and body mass

Protein malnutrition leads to growth retardation that can be reversed through catch-up growth, once normative nutrition is restored. Because growth is a dynamic process, catch-up capacity is likely influenced by the maturity of the animal and/or the duration of the insult, in addition to the type of insult experienced. We compared length of malnutrition, sexual dimorphism, body mass, and skeletal growth. Eighty Rattus norvegicus were divided into 10 treatment groups (five diets; male and female) and followed for more than 1 year. At weaning, animals were placed on either a control or low-protein isocaloric diet. Three experimental groups were switched to the control diet at 40, 60, or 90 days. Beginning with 21 days of age, animals were weighed daily and radiographed throughout the study. To determine the presence of catch-up growth, growth rates (GRs) were calculated (linear regression) for 20-day time spans before and after diet changes and compared among treatment groups. Targeted growth was measured as final size or as the coefficient of variation with age. These results show that 1) protein-restricted animals experience catch-up growth with dietary rehabilitation; 2) for females, catch-up GRs are proportional to GRs in control animals at the same age as the timing of dietary rehabilitation but not for males; and 3) targeted growth was observed in some, but not all, aspects of anatomy. The length of the tibia and humerus was indistinguishable from controls, regardless of length of malnutrition or gender, whereas the ulna and male body mass exceeded control sizes. Although most measures decreased in variation with ontogeny, the tibia failed to do so. These results support a complex biological regulation of catch-up and targeted growth. The implications for selection are that flexible and responsive developmental trajectories may have an advantage over those programed into a single size.

Intestine transplantation in children: update 2010

This article reviews the current status of pediatric intestinal transplantation, focusing on referral and listing criteria, surgical techniques, patient management, monitoring, complications after transplant, and short- and long-term patient outcome. Intestine transplantation has become the standard of care for children who develop life-threatening complications associated with intestinal failure. The results of intestinal failure treatment have significantly improved in the last decade following the establishment of gut rehabilitation programs and advances in transplant immunosuppressive protocols, surgical techniques, and posttransplant monitoring. The 1-year patient survival is now 80% and more than 80% of the children who survive the transplant are weaned off parenteral nutrition. Early referral for pretransplant assessment and careful follow-up after transplant with prompt recognition and treatment of transplant-related complications are key factors contributing to superior patient outcomes and survival. The best results are being obtained at high-volume centers with survival rates of up to 75% at 5 years.

Current status of small bowel and multivisceral transplantation

Intestinal transplantation has shown exceptional growth over the past 20 years with remarkable progress. As with other solid organ transplants, intestinal transplantation has moved out of the experimental realm to become the stan dard of care for many patients with intestinal failure. Intestinal transplantation may soon be extended routinely to patients who, although not strictly meeting the criteria for intestinal failure, may benefit from intestinal transplantation, such as patients who have nonresectable indolent tumors or diffuse thrombosis of the portomesenteric system. As clinical experience has increased with intestinal transplantation, outcomes have improved. The currently reported 1-year graft and patient survival rate is 80%, which approaches that for other solid abdominal organs. Unfortunately, most of the gains in survival are seen in the first postoperative year, with long-term survival remaining basically unchanged since the early 1990s. With improved outcomes, more centers have entered into the intestinal transplant arena. In the United States alone, 20 centers performed at least one intestinal transplant in 2007. Increase in access to intestinal transplantation and more widespread awareness of this option likely will result in a consistent increase in the number of yearly transplants for the foreseeable future. Immunosuppressive regimens continue to evolve, with induction therapy being the major change in the past 5 years. Although rejection rates in the first year after transplant have been reduced by induction therapy, long-term side effects of heavy immunosuppression continue to weigh negatively on transplant outcomes. The future for immunosuppression lies in two areas: (1) individual monitoring of the immunosuppression level for each individual patient and (2) development of serum and tissue markers for the early identification of rejection. It is likely that a combination of technologies will allow immunosuppression to be tailored to each recipient. Development of these approaches to immunosuppression is necessary to predict graft dysfunction ahead of irreversible graft injury and allows adjustments in immunosuppression before the onset of rejection. Intestinal transplantation continues to be performed only in situations in which all other therapeutic modalities have failed. No randomized trials compare intestinal transplantation to long-term PN to establish guidelines for a timely referral for this treatment option. Late referral remains a crippling problem in the field of intestinal transplantation, with a great number of patients in need of simultaneous liver transplantation at the time of listing for intestinal transplantation. Early referral for isolated intestinal transplant will reduce the need for simultaneous multiorgan transplants and increase the residual organs available for patients in need of (primarily) liver transplantation.