Pediatric small bowel transplantation

Present state of intestinal transplantation in Japan

INTRODUCTION

Intestinal transplantation (ITx) is the ultimate treatment for intestinal failure (IF). In Japan, most cases of IF are a result of pediatric disease, including secondary or congenital intestinal disease or allied disorders of Hirschsprung's disease. Here, we report the results of the Japanese ITx registry.

METHODS

A web-based survey form was completed. We investigated the number, age, sex, indication, surgical procedure, immunosuppressants, postoperative course, and the effects of transplantation in patients who underwent cadaveric or living-donor ITx.

RESULTS

By the end of 2022, 42 cases of ITx have been performed in 38 patients in Japan. The donor sources included cadavers (29 cases) and living donors (13 cases). The surgical method was isolated ITx (N = 40) and combined liver and ITx (n = 2). Survival rates were 92%, 73%, and 59% at 1 year, 5 years, and 10 years, respectively. Ninety percent of patients completely discontinued parenteral nutrition. Approximately 80% of the patients had a performance status of 1 or less, indicating that the QOL of patients after ITx was extremely good.

CONCLUSION

The results of ITx are acceptable to treat IF patients and the QOL after transplantation is also good.

Deceased donor organ allocation in pediatric transplantation: A historical narrative

BACKGROUND

Since the earliest clinical successes in solid organ transplantation, the proper method of organ allocation for children has been a contentious subject. Over the past 30-35 years, the medical and social establishments of various countries have favored some degree of preference for children on the respective waiting lists. However, the specific policies to accomplish this have varied widely and changed frequently between organ type and country.

METHODS

Organ allocation policies over time were examined. This review traces the reasons behind and the measures/principles put in place to promote early deceased donor transplantation in children.

RESULTS

Preferred allocation in children has been approached in a variety of ways and with varying degrees of commitment in different solid organ transplant disciplines and national medical systems.

CONCLUSION

The success of policies to advantage children has varied significantly by both organ and medical system. Further work is needed to optimize allocation strategies for pediatric candidates.

Operational tolerance after pediatric composite liver-pancreas-intestine transplantation following severe graft-versus-host disease

BACKGROUND

While operational tolerance has been previously described in isolated intestinal transplant, reports of this phenomenon in combined liver-intestine transplant are lacking.

CASE DESCRIPTION

We detail a unique case of a patient who received a composite allograft including liver, pancreas, and small bowel due to short gut syndrome secondary to gastroschisis complicated by volvulus. The indication for transplantation was permanent dependence on total parenteral nutrition, end-stage liver disease, recurrent sepsis, and persistent stomal variceal hemorrhage. The patient developed severe graft-versus-host disease with grade 3 skin involvement, ophthalmic, and pulmonary involvement with 53% donor T-cell chimerism. She required aggressive therapy including high-dose methylprednisolone, rituximab, cyclophosphamide, and alemtuzumab. Due to infection concerns following depletion of her lymphocytes, immunosuppression was discontinued with close surveillance of her allograft. Nearly 10 years later, the patient has continued off all immunosuppression without evidence of rejection or graft dysfunction and demonstrates immunocompetence with normal functional immune assays and development of appropriate live vaccination titers.

CONCLUSION

This report of operational tolerance following pediatric composite liver-pancreas-intestine transplantation provides evidence that the complex immunologic balance in intestinal transplantation may on rare occasions favor immunosuppression reduction or even discontinuation. Future trials of immunosuppression minimization in this population may be warranted.

Proteomic biomarkers in short bowel syndrome : are we ready to use them in clinical activity?

Introduction: Short bowel syndrome (SBS) is a clinical condition that can affect childhood and adult patients. Biomarker research is expected to be a new frontier in the clinical application, helpful for patients and health-care systems.Areas covered: SBS is usually a consequence of a massive intestinal resection that leads to an intestinal failure because of the reduction of absorptive surface, bacterial overgrowth, and faster intestinal transit. This new condition requires a multidisciplinary expertise to achieve again digestive autonomy. Parental nutrition (PN) supports nutritional status in SBS patients while the new guidelines on intestinal transplantation confirm its strict indication only for patients at actual risk of death on PN. A PubMed literature review from the 1980s up to date was performed, highlighting proteomic biomarkers and growth factor therapies that have shown so far promising results in SBS patients.Expert opinion: Apart from a few specific biomarkers and growth factors, the discovery of specific molecular events is currently under investigation of the proteomic analysis and could potentially represent fundamental, future changes in prevention, diagnosis, therapeutic management, and experimental practices in SBS.

Effectiveness of a central line associated blood stream infection protocol in a pediatric population

BACKGROUND

Central line associated bloodstream infections are a common cause of bacteremia and sepsis in pediatric patients with intestinal failure, secondary to long-term CVC use.

METHODS

An IRB approved retrospective chart review was conducted on TPN-dependent patients with IF who had an identified CLABSI and presented to Children's of Alabama's emergency department (ED) and were admitted to the hospital.

RESULTS

Forty-four patients were included in the study, 28 in the first 18-month period and 26 in the second, with 10 in both populations. After implementation, mean time from ED presentation to antibiotic ordered and ED admission to antibiotic administered were lower. Mean time between antibiotic administration and admission to the floor was greater, and number of infectious disease consultations was greater. Floor-ICU transfers were lower, readmissions within 30 days was similar, and mean length of stay was similar.

CONCLUSION

A collaborative, multidiscipline-supported protocol for the care of patients with IF presenting to the ED enhances efficiency of antibiotic ordering/administration, as well as reduces the number of unplanned floor-ICU transfers.

Isolation and characterisation of mouse intestinal mesoangioblasts

AIMS AND OBJECTIVES

Children suffering from intestinal failure (IF) endure considerable morbidity and overall have poor survival rates, complicated by the shortage of organs available for transplantation. Therefore, new therapeutic approaches are pivotal if outcomes are to be improved. Over the past years, tissue engineering (TE) has emerged as a possible alternative treatment for many congenital and acquired conditions. TE aims at creating bioengineered organs by means of combining scaffolds with appropriate cell types, which in the intestine are organised within a multilayer structure. In order to generate functional intestine, this cellular diversity and organisation will need to be recreated. While the cells for the epithelial, neural and vascular compartments have been well defined, so far, less attention has been put on the muscular compartment. More recently, mesoangioblasts (MABs) have been identified as a novel source for tissue regeneration since they are able to give rise to vascular and other mesodermal derivatives. To date MABs have not been successfully isolated from intestinal tissue. Therefore, our aim was to demonstrate the possibility of isolating MABs from adult mouse small intestine.

MATERIALS AND METHODS

All experiments were carried out using small intestinal tissues from C57BL/6J mice. We applied an established protocol for MAB isolation from the isolated neuromuscular layer of the small intestine. Cultured cells were stained for Ki67 to assess proliferation rates as well as for a panel of pericyte markers to determine their phenotype.

RESULTS

Cells were successfully isolated from gut biopsies. Cultured cells showed good proliferative capacity and positivity for at least three pericytes markers found in vessels of the gut neuromuscular wall: neuron-glial antigen 2, alkaline phosphatase and platelet-derived growth factor β.

CONCLUSION

This proof-of-principle study lays the foundation for further characterization of MABs as a possible cell source for intestinal smooth muscle regeneration and TE.

Antibody-mediated rejection in pediatric small bowel transplantation: Capillaritis is a major determinant of C4d positivity in intestinal transplant biopsies

The diagnostic criteria for antibody-mediated rejection (ABMR) after small bowel transplantation (SBT) are not clearly defined, although the presence of donor-specific antibodies (DSAs) has been reported to be deleterious for graft survival. We aimed to determine the incidence and prognostic value of DSAs and C4d in pediatric SBT and to identify the histopathologic features associated with C4d positivity. We studied all intestinal biopsies (IBx) obtained in the first year posttransplantation (N = 345) in a prospective cohort of 23 children. DSAs and their capacity to fix C1q were identified by using Luminex technology. Eighteen patients (78%) had DSAs, and 9 had the capacity to fix C1q. Seventy-eight IBx (22.6%) were C4d positive. The independent determinants of C4d positivity were capillaritis grades 2 and 3 (odds ratio [OR] 4.02, P = .047 and OR 5.17, P = .003, respectively), mucosal erosion/ulceration (OR 2.8, P = .019), lamina propria inflammation grades 1 and 2/3 (OR 1.95, P = .043 and OR 3.1, P = .016, respectively), and chorion edema (OR 2.16, P = .028). Complement-fixing DSAs and repeated C4d-positive IBx were associated with poor outcome (P = .021 and P = .001, respectively). Our results support that capillaritis should be considered as a feature of ABMR in SBT and identify C1q-fixing DSAs and repeated C4d positivity as potential markers of poor outcome.

[Infections in immunocompromised patients (II). The transplanted patient]

Los receptores de los diferentes tipos de trasplante presentan un riesgo elevado de infección. En los trasplantados de precursores hematopoyéticos predominan las infecciones nosocomiales. Durante el periodo posprendimiento temprano (30-100 días tras la infusión del trasplante), la incidencia de infección es más elevada en pacientes con enfermedad de injerto contra huésped. En el pulmón pueden aparecer lesiones nodulares por infección fúngica invasora o bien un patón difuso habitualmente secundario a infección vírica o a neumonía por P. jirovecii. Después de los primeros 100 días persiste un moderado riesgo de infección por microorganismos convencionales y oportunistas, como la infección tardía por CMV. Los avances en las técnicas quirúrgicas y el empleo de calcineurínicos han reducido la mortalidad por infecciones en trasplantados de órgano sólido. Durante el primer mes, son frecuentes las infecciones nosocomiales; entre el primer y sexto mes son más frecuentes las infecciones oportunistas dependientes de la inmunidad celular y a partir de sexto mes el riesgo baja y predominan las infecciones comunitarias semejantes a las de los pacientes inmunocompetentes.

Current treatment paradigms in pediatric short bowel syndrome

Pediatric short bowel syndrome (SBS) is a serious condition which occurs in children with congenital or acquired reduction in length of the small intestine. SBS results in excessive fluid loss, nutrient malabsorption, electrolyte abnormalities, increased susceptibility to infections, parenteral nutrition associated complications and affects weight gain and growth. In children, SBS is debilitating and uniformly fatal without treatment. The primary goal of treatment is to restore enteral autonomy and reduce long-term dependence on parenteral support by increasing the absorptive potential of the remnant intestine. In this review, the medical and surgical management of SBS including pharmacologic agents, parenteral nutrition, dietary strategies, surgical lengthening procedures, and small bowel transplant will be discussed.

Gut Permeability and Glucose Absorption Are Affected at Early Stages of Graft Rejection in a Small Bowel Transplant Rat Model

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Background

Intestinal transplantation (ITx) faces many challenges due to the complexity of surgery and to the multiple immunological reactions that lead to the necessity of rigorous follow-up for early detection of acute cellular rejection (ACR). Our aim was to determine the kinetics of ACR using an experimental ITx model, with emphasis in the characterization of the process using different approaches, including the use of functional assays of absorptive and barrier function.

Methods

ITx in rats conducting serial sampling was performed. Clinical monitoring, graft histology, proinflammatory gene expression, and nitrosative stress determination were performed. Also, glucose absorption, barrier function using ovalbumin translocation, and contractile function were analyzed.

Results

The model used reproduced the different stages of ACR. Allogeneic ITx recipients showed signs of rejection from postoperative day (POD) 5, with increasing severity until 12 POD. Histological evaluation showed mild rejection in early sampling and severe rejection at late stages, with alterations in all graft layers. IL-6, CXCL 10, IFNg, and nitrite plasmas levels showed behavior coincident with histopathology. Remarkably, allogeneic grafts showed a marked alteration of glucose absorptive capacity from POD 5 that was sustained until endpoint. Coincidently, barrier function alteration was evidenced by luminal ovalbumin translocation to serum. Contractile function was progressively impaired along ACR.

Conclusions

Glucose absorption and barrier function are altered at early stages of ACR when histological alterations or gene expression changes were much subtle. This observation may provide simple evaluation tools that could be eventually translated to the clinics to contribute to early ACR diagnosis.

Adipose-derived mesenchymal stem cells suppress of acute rejection in small bowel transplantation

BACKGROUND/AIMS

Adipose-derived mesenchymal stem cells (ADSCs) possess immunosuppressive activity and hold promise in autologous cell-based therapies. The aim of this study was to determine whether autologous ADSCs can improve outcomes in the rat small bowel transplantation (SBT) model.

MATERIALS AND METHODS

Allogeneic SBT followed by implantation of autologous ADSCs through the penile vein was conducted in Brown-Norway (BN) donor rats with Lewis (LEW) recipient rats infused with phosphate buffered solution as the control. Allograft and recipient peripheral blood were obtained. We assessed histopathology, apoptosis, cytokines, and regulatory T cells (Tregs). One-way analysis of variance was applied to assess the significance of the data.

RESULTS

It was found that ADSCs significantly reduced acute rejection and improved the allograft's survival rate. In addition, there were significantly fewer apoptotic cells in allograft mucosae in the ADSC group in comparison with the control group. Furthermore, levels of interleukin (IL)-10 and transforming growth factor-β1 were significantly elevated, whereas those of IL-2 and IL-17 levels were significantly reduced in the ADSC group when compared to the control group. Moreover, flow cytometry analysis revealed that there were significantly more peripheral Tregs after the infusion of ADSCs.

CONCLUSIONS

These results demonstrate that implanted autologous ADSCs improve allogeneic small bowel allograft outcomes by attenuating the acute rejection and reducing inflammatory responses.

Intestinal transplantation in children: current status

Intestinal transplantation (IT) is the least common form of organ transplantation; however, it has shown exceptional growth and improvement in graft survival rates over the past two decades mainly due to better outcomes achieved during the first year of transplantation (76 % at 1 year), due to improvement in surgical techniques and the development of better immunosupressive therapies as we understand more about the relationship between the recipient and host immune system. There are still ongoing issues with chronic rejection and long-term survival. Intestinal transplantation is still an acceptable therapy for patients with intestinal failure (IF), but it is generally reserved for patients who develop severe and life-threatening complications despite standard therapies, or those who are not able to maintain a good quality of life. The purpose of this review is to describe the current status, indications, outcomes and advances in the field of intestinal transplantation.