Current status of pediatric intestinal failure, rehabilitation, and transplantation: summary of a colloquium

Impact of Immunoglobulin Therapy in Intestinal Transplant Recipients With Posttransplantation Hypogammaglobulinemia

BACKGROUND

Severe hypogammaglobulinemia (HGG) (IgG <400 mg/dL) following intestinal transplantation is common. Although IgG replacement therapy is commonly used, clinical outcomes associated with increasing IgG levels to >400 mg/dL are not well described.

METHODS

Kaplan-Meier analysis was performed to estimate survival, the log-rank test to compare survival distributions between groups, and the Fisher exact test to determine the association between HGG and rejection.

RESULTS

A total of 23 intestinal transplant (IT) recipients with a median age of 2.3 years (range, 0.7-41 years) at the time of HGG diagnosis were included. The types of transplants were liver-small bowel (73.9%), liver-small bowel-kidney (8.7%), and small bowel only (17.4%). The 3-year survival after the diagnosis of HGG was 50.2% (95% confidence interval [CI] = 28.2%-68.7%). There was no difference in survival (P = .67) when patients were dichotomized based upon IgG level at last follow-up (IgG ≥400 mg/dL, n = 14; and IgG <400 mg/dL, n = 9). There was no also evidence of an association between survival and: total dose (P = .58), frequency (P = .11), and number of IgG doses administered (P = .8). There was no difference in survival between patients receiving (n = 12) or not receiving (n = 11) cytomegalovirus hyperimmunoglobulin (P = .10).

CONCLUSIONS

Improved survival rates were not found in our IT recipients with severe HGG with immunoglobulin therapy to IgG levels of ≥400 mg/dL, even when cytomegalovirus hyperimmunoglobulin was administered.

Early neurodevelopmental outcomes of infants with intestinal failure

BACKGROUND

The survival rate of infants and children with intestinal failure is increasing, necessitating a greater focus on their developmental trajectory.

AIMS

To evaluate neurodevelopmental outcomes in children with intestinal failure at 0-15months corrected age.

STUDY DESIGN

Analysis of clinical, demographic and developmental assessment results of 33 children followed in an intestinal rehabilitation program between 2011 and 2014. Outcome measures included: Prechtl's Assessment of General Movements, Movement Assessment of Infants, Alberta Infant Motor Scale and Mullen Scales of Early Learning. Clinical factors were correlated with poorer developmental outcomes at 12-15months corrected age.

RESULTS

Thirty-three infants (17 males), median gestational age 34weeks (interquartile range 29.5-36.0) with birth weight 1.98kg (interquartile range 1.17-2.50). Twenty-nine (88%) infants had abnormal General Movements. More than half had suspect or abnormal scores on the Alberta Infant Motor Scale and medium to high-risk scores for future neuromotor delay on the Movement Assessment of Infants. Delays were seen across all Mullen subscales, most notably in gross motor skills. Factors significantly associated with poorer outcomes at 12-15months included: prematurity, low birth weight, central nervous system co-morbidity, longer neonatal intensive care admission, necrotizing enterocolitis diagnosis, number of operations and conjugated hyperbilirubinemia.

CONCLUSION

Multiple risk factors contribute to early developmental delay in children with intestinal failure, highlighting the importance of close developmental follow-up.

Difficulties, guidelines and review of developing an acute rejection model after rat intestinal transplantation

Experimental small bowel transplantation (SBT) in rats has been proven to be a useful tool for the study of ischemia-reperfusion and immunological aspects related to solid organ transplantation. However, the model is not completely refined, specialized literature is scarce and complex technical details are typically omitted or confusing. Most studies related to acute rejection (AR) use the orthotopic standard, with small sample sizes due to its high mortality, whereas those studying chronic rejection (CR) use the heterotopic standard, which allows longer term survival but does not exactly reflect the human clinical scenario. Various animal strains have been used, and the type of rejection and the timing of its analysis differ among authors. The double purpose of this study was to develop an improved unusual AR model of SBT using the heterotopic technique, and to elaborate a guide useful to implement experimental models for studying AR. We analyzed the model's technical details and expected difficulties in overcoming the learning curve for such a complex microsurgical model, identifying the potential problem areas and providing a step-by-step protocol and reference guide for future surgeons interested in the topic. We also discuss the historic and more recent options in the literature.

The Surgical Approach to Short Bowel Syndrome - Autologous Reconstruction versus Transplantation

BACKGROUND

Short bowel syndrome (SBS) is a state of malabsorption resulting from massive small bowel resection leading to parenteral nutrition (PN) dependency. Considerable advances have been achieved in the medical and surgical management of SBS over the last few decades.

METHODS

This review discusses in detail the surgical approach to SBS.

RESULTS

Widespread use of PN enables long-term survival in patients with intestinal failure but at the cost of PN-associated life-threatening complications including catheter-associated blood stream infection, venous thrombosis, and liver disease. The goal of management of intestinal failure due to SBS is to enable enteral autonomy and wean PN by means of a multi-disciplinary approach. Availability of modified enteral feeding formulas have simplified nutrition supplementation in SBS patients. Similarly, advances in the medical field have made medications like growth hormone and glucagon-like peptide (GLP2) available to improve water and nutrient absorption as well as to enable achieving enteral autonomy. Autologous gastrointestinal reconstruction (AGIR) includes various techniques which manipulate the bowel surgically to facilitate the bowel adaptation process and restoration of enteral nutrition. Ultimately, intestinal transplantation can serve as the last option for the cure of intestinal failure when selectively applied.

CONCLUSION

SBS continues to be a challenging medical problem. Best patient outcomes can be achieved through an individualized plan, using various AGIR techniques to complement each other, and intestinal transplantation as a last resort for cure. Maximum benefit and improved outcomes can be achieved by caring for SBS patients at highly specialized intestinal rehabilitation centers.

Health-related quality of life in pediatric intestinal transplantation

To determine HRQOL after pediatric intestinal transplantation. Thirty-four IT survivors from 1999 to 2012 were asked to complete age-specific HRQOL non-disease-specific questionnaires: TAPQOL (0-4 yr), KINDL-R (5-7 yr; 8-12 yr; 13-17 yr), and SF-36v2 (>18 yr), all validated with Spanish population. Primary caregiver completed a SF-36 questionnaire and CBI. Thirty-one participants were included. Median age was 10.2 yr (1-29) and time after transplant 4.4 yr (0-13). Overall patient scores were 78.2 ± 10.6 (n = 8), 83.3 ± 9.7 (n = 6), 72.2 ± 9.21 (n = 6), 80.5 ± 12.4 (n = 7), and 82.2 ± 12.4 (n = 4) for each age group. Highest scores were obtained for vitality (group I), self-esteem (group IV), and physical and social functioning and emotions (group V). Lowest scores were obtained in appetite and behavior (I), family and school (III), and chronic disease perception (III, IV). No significant differences were found between caregivers and their children. CBI showed stress in 52%. SF-36 for caregivers was lower than general population. No significant differences were found depending on relevant clinical and sociodemographic data. HRQOL was acceptable and improved with age and time since transplantation. Parents had a slighter own QOL and worse perception of health than their children. When successful, intestinal transplantation allows a normal life in most patients and can be offered as an attractive option.

Non-transplant surgery for short bowel syndrome

The goal of any treatment programme for short bowel syndrome SBS is to achieve nutritional enteral autonomy. This must begin with conservation of as much bowel as possible from the time of first presentation. Frequent causes of the short bowel syndrome are intestinal atresia, necrotizing enterocolitis, midgut volvulus, extended intestinal aganglionosis, 'vanished gut' often associated with gastroschisis and occasionally catastrophic trauma. Atresia is more amenable to successful surgery than other causes, except when associated with gastroschisis. Intrinsic dysmotility has a poor prognosis. Intestinal lengthening procedures are only indicated if there is sufficient bowel dilatation. Extended intestinal aganglionosis is rarely amenable to any form of non-transplant surgery. Options available are to conserve bowel, close stomas early (use all available bowel to the maximum or even re-feed stoma effluent into the distal unused bowel), release adhesions causing obstruction, resect strictures, taper or excise localized dilatations and finally address dilated bowel with lengthening and tailoring operations. These procedures aim to improve effective peristalsis, thereby reducing bacterial overgrowth and improving nutrient contact with enteral mucosa to maximize absorption and intestinal adaptation. The Bianchi longitudinal splicing operation and the serial transverse enteroplasty operations have stood the test of time in providing considerable improvement in enteral nutritional autonomy in around 60% of cases. In SBS without dilatation attempts at 'mechanically' delaying transit (nipple valves, reversed bowel segments, colon interposition) have had inconsistent outcomes. Growing neomucosa and lengthening bowel by longitudinal stretch are still experimental.

Breast milk is better than formula milk in preventing parenteral nutrition-associated liver disease in infants receiving prolonged parenteral nutrition

BACKGROUND AND AIM

Breast milk has been shown to be associated with greater success with regard to weaning children with intestinal failure off parenteral nutrition (PN). There are only a few studies investigating the role of breast milk in decreasing PN-associated liver disease (PNALD). The aim of our study was to determine whether breast milk is better than formula milk in preventing PNALD in infants receiving PN for >4 weeks.

METHODS

We conducted a retrospective analysis of newborns requiring prolonged parenteral nutrition. We divided the sample into 3 different groups (exclusive breast-feeding, exclusive formula-feeding, and mixed feeding. We compared baseline characteristics, feeding profiles and liver function tests, and liver enzymes among the 3 groups.

RESULTS

Among infants receiving PN for >4 weeks, we found that infants who were fed only breast milk were significantly less likely to develop PNALD (34.6%) compared with those who were fed only formula milk (72.7%; P = 0.008). The mean maximum conjugated bilirubin (P = 0.03) and the mean maximum aspartate aminotransferase were significantly lower in the breast-fed group (P = 0.04) compared with the formula-fed group. Among the mixed-feeding group, infants who received a higher percentage of breast milk showed a significant negative correlation with the mean maximum conjugated bilirubin. (Pearson correlation -0.517, P = 0.027). The mean number of days receiving PN and the average daily lipid intake in the 2 groups was not significantly different.

CONCLUSIONS

As a modality for early enteral nutrition, breast milk is protective against the development of PNALD in infants receiving PN for >4 weeks.

Incidence, prevention, and treatment of parenteral nutrition-associated cholestasis and intestinal failure-associated liver disease in infants and children: a systematic review

BACKGROUND

Cholestasis is a significant life-threatening complication in children on parenteral nutrition (PN). Strategies to prevent/treat PN-associated cholestasis (PNAC) and intestinal failure-associated liver disease (IFALD) have reached moderate success with little supporting evidence. Aims of this systematic review were (1) to determine the incidence of PNAC/IFALD in children receiving PN for ≥ 14 days and (2) to review the efficacy of measures to prevent/treat PNAC/IFALD.

METHODS

Of 4696 abstracts screened, 406 relevant articles were reviewed, and studies on children with PN ≥ 14 days and cholestasis (conjugated bilirubin ≥ 2 mg/dL) were included. Analyzed parameters were (1) PNAC/IFALD incidence by decade and by PN length and (2) PNAC/IFALD prevention and treatment (prospective studies).

RESULTS

Twenty-three articles (3280 patients) showed an incidence of 28.2% and 49.8% of PNAC and IFALD, respectively, with no evident alteration over the last decades. The incidence of PNAC was directly proportional to the length of PN (from 15.7% for PN ≤ 1 month up to 60.9% for PN ≥ 2 months; P < .0001). Ten studies on PNAC met inclusion criteria. High or intermediate-dose of oral erythromycin and aminoacid-free PN with enteral whey protein gained significant benefits in preterm neonates (P < .05, P = .003, and P < .001, respectively). None of the studies reviewed met inclusion criteria for treatment.

CONCLUSIONS

The incidence of PNAC/IFALD in children has no obvious decrease over time. PNAC is directly correlated to the length of PN. Erythromycin and aminoacid-free PN with enteral whey protein have shown to prevent PNAC in preterm neonates. There is a lack of high-quality prospective studies, especially on IFALD.

Incidence, timing, and significance of early hypogammaglobulinemia after intestinal transplantation

BACKGROUND

Despite recent advances in intestinal transplantation (ITx), infection (INF) and acute cellular rejection (ACR) remain major causes of patient and graft loss. Studies in other solid-organ transplantations indicate that low levels of serum immunoglobulin G (IgG) negatively impact outcomes. To date, there have been no studies on IgG after ITx.

METHODS

A retrospective review of an IgG measurement protocol in primary ITx recipients between 2007 and 2011 was undertaken. IgG levels were measured at the time of evaluation, transplantation, and at weekly intervals for 2 months. Hypogammaglobulinemia (HGG) was defined as IgG levels below the lower limit of the 95% confidence interval for age. Associations between HGG, INF, and ACR were tested, and the incidence and timing of INF and ACR were compared.

RESULTS

Thirty-four patients were transplanted at a mean (SD) age of 12.4 (17.2) years. Most were Latino children with gastroschisis who received multivisceral grafts. Relative to pre-ITx levels, a statistically significant decrease in IgG levels was observed after ITx (P<0.05). Twenty patients (59%) developed HGG during the post-ITx period at a mean (SD) of 9.8 days. No significant associations were identified between HGG and INF or ACR.

CONCLUSIONS

This is the first study to describe serum IgG levels after ITx. A marked decrease in serum IgG levels was observed early on, in most patients. The etiology is potentially related to immunotherapy. HGG was not associated with INF or ACR, possibly related to the sample size and our practice of exogenous intravenous immunoglobulin replacement.

Intestinal transplantation in infants with intestinal failure

Intestinal failure (IF) occurs when a person's functional intestinal mass is insufficient. Patients with IF are placed on parenteral nutrition (PN) while efforts are made to restore intestinal function through surgical or medical intervention. Patients who fail standard IF therapies may be candidates for intestinal transplantation (IT). Clinical outcomes for IT have improved to make this therapy the standard of care for patients who develop complications of PN. The timing of referral for IT is critical because accumulated complications of PN can render the patient ineligible for IT or can force the patient to await multiorgan transplantation.

Mucosal plasma cell barrier disruption during intestine transplant rejection

BACKGROUND

Intestinal allograft mucosa undergoes repopulation with host immunocytes. However, critical changes within key immunocyte subsets are not known.

METHODS

To explain acute cellular rejection after intestine transplantation (ITx) on the basis of altered mucosal immunocytes, rejecting and rejection-free ITx allografts (n=17) were compared with genome-wide expression arrays. Cells identified by cell/lineage-specific genes were evaluated by immunohistochemistry. The corresponding phenotype and donor-specific alloreactivity were characterized in peripheral blood. Time-dependent changes in candidate cell(s) were evaluated in biopsies from an independent cohort of 12 children with ITx.

RESULTS

Among 107 differentially expressed genes, three B-cell lineage-specific genes, CCR10, STAP1, and IGLL1, were down-regulated during ITx rejection and were selected for and achieved technical quantitative reverse transcription polymerase chain reaction replication. Down-regulation of the immunoglobulin (Ig)A+ plasma cell-specific CCR10 gene correlated with decreased mature mucosal CD138+ plasma cell numbers in corresponding biopsy specimens (r=0.761, P=0.006) and inversely correlated with enhanced alloreactivity of CD154+ T-cytotoxic memory cells (r=-0.56, P=0.031), which predict acute cellular rejection with high sensitivity. An independent cohort of serial biopsy specimens from 12 ITx recipients (1) confirmed relative CD138+ plasma cell depletion during rejection (P=0.042) and (2) showed increased IgG+-to-IgA+ cell ratios within 4 hr of reperfusion in rejection-prone allografts (P=0.037) and during ITx rejection (P=0.025), compared with rejection-free allografts. No differences existed late after ITx. Increased peripheral IgG+ CD27+ CD19+ memory B cells (P=0.004) were seen during ITx rejection in archived peripheral blood lymphocyte from test and replication cohorts.

CONCLUSIONS

Protracted depletion of the mucosal CD138+ plasma cell barrier and early mucosal infiltration with memory IgG+ cells characterize the rejection-prone intestine allograft. Mucosal IgA+ plasma cell barrier reconstitution may augur resolution of ITx rejection.

How regenerative medicine and tissue engineering may complement the available armamentarium in gastroenterology?

The increasing shortage of donors and the adverse effects of immunosuppression have restricted the impact of solid organ transplantation. Despite the initial promising developments in xenotransplantation, roadblocks still need to be overcome and this form of organ support remains a long way from clinical practice. While hepatocyte transplantation may be effectively correct metabolic defects, it is far less effective in restoring liver function than liver transplantation. Tissue engineering, using extracellular matrix scaffolds with an intact but decellularized vascular network that is repopulated with autologous or allogeneic stem cells and/or adult cells, holds great promise for the treatment of failure of organs within gastrointestinal tract, such as end-stage liver disease, pancreatic insufficiency, bowel failure and type 1 diabetes. Particularly in the liver field, where there is a significant mortality of patients awaiting transplant, human bioengineering may offer a source of readily available organs for transplantation. The use of autologous cells will mitigate the need for long term immunosuppression thus removing a major hurdle in transplantation.

Preformed and de novo donor specific antibodies in visceral transplantation: long-term outcome with special reference to the liver

Despite improvement in early outcome, rejection particularly chronic allograft enteropathy continues to be a major barrier to long-term visceral engraftment. The potential role of donor specific antibodies (DSA) was examined in 194 primary adult recipients. All underwent complement-dependent lymphocytotoxic crossmatch (CDC-XM) with pre- and posttransplant solid phase HLA-DSA assay in 156 (80%). Grafts were ABO-identical with random HLA-match. Liver was included in 71 (37%) allografts. Immunosuppression was tacrolimus-based with antilymphocyte recipient pretreatment in 150 (77%). CDC-XM was positive in 55 (28%). HLA-DSA was detectable before transplant in 49 (31%) recipients with 19 continuing to have circulating antibodies. Another 19 (18%) developed de novo DSA. Ninety percent of patients with preformed DSA harbored HLA Class-I whereas 74% of recipients with de novo antibodies had Class-II. Gender, age, ABO blood-type, cold ischemia, splenectomy and allograft type were significant DSA predictors. Preformed DSA significantly (p < 0.05) increased risk of acute rejection. Persistent and de novo HLA-DSA significantly (p < 0.001) increased risk of chronic rejection and associated graft loss. Inclusion of the liver was a significant predictor of better outcome (p = 0.004, HR = 0.347) with significant clearance of preformed antibodies (p = 0.04, OR = 56) and lower induction of de novo DSA (p = 0.07, OR = 24). Innovative multifaceted anti-DSA strategies are required to further improve long-term survival particularly of liver-free allografts.

Long-term survival, nutritional autonomy, and quality of life after intestinal and multivisceral transplantation

OBJECTIVE

To assess long-term survival, graft function, and health-related quality of life (QOL) after visceral transplantation.

BACKGROUND

Despite continual improvement in early survival, the long-term therapeutic efficacy of visceral transplantation has yet to be defined.

METHODS

A prospective cross-sectional study was performed on 227 visceral allograft recipients who survived beyond the 5-year milestone. Clinical data were used to assess outcome including graft function and long-term survival predictors. The socioeconomic milestones and QOL measures were assessed by clinical evaluation, professional consultation, and validated QOL inventory.

RESULTS

Of 376 recipients, 227 survived beyond 5 years, with conditional survival of 75% at 10 years and 61% at 15 years. With a mean follow-up of 10 ± 4 years, 177 (92 adults, 85 children) are alive, with 118 (67%) recipients 18 years or older. Nonfunctional social support and noninclusion of the liver in the visceral allograft are the most significant survival risk factors. Nutritional autonomy was achievable in 160 (90%) survivors, with current serum albumin level of 3.7 ± 0.5 gm/dL and body mass index of 25 ± 6 kg/m(2). Despite coexistence or development of neuropsychiatric disorders, most survivors were reintegrated to society with self-sustained socioeconomic status. In parallel, most of the psychological, emotional, and social QOL measures significantly (P < 0.05) improved after transplantation. Current morbidities with potential impact on global health included dysmotility (59%), hypertension (37%), osteoporosis (22%), and diabetes (11%), with significantly (P < 0.05) higher incidence among adult recipients.

CONCLUSIONS

With new tactics to further improve long-term survival including social support measures, visceral transplantation has achieved excellent nutritional autonomy and good QOL.