Present prospects and future perspectives of intestinal and multivisceral transplantation

Innovative surgical techniques in the intestine and multivisceral transplant

PURPOSE OF REVIEW

This timely review delves into the evolution of multivisceral transplantation (MVT) over the past six decades underscoring how advancements in surgical techniques and immunosuppression have driven transformation, to provide insight into the historical development of MVT, shedding light on its journey from experimentation to a valuable clinical approach.

RECENT FINDINGS

The review presents contemporary enhancements in surgical methods within the context of intestinal transplantation. The versatility of MVT is emphasized, accommodating diverse organ combinations and techniques. Both isolated intestinal transplantation (IIT) and MVT have seen expanded indications, driven by improved parenteral nutrition, transplantation outcomes, and surgical innovations. Surgical techniques are tailored based on graft type, with various approaches for isolated transplantation. Preservation strategies and ostomy techniques are also covered, along with graft assessment advancements involving donor-specific antibodies.

SUMMARY

This review's findings underscore the remarkable evolution of MVT from experimental origins to a comprehensive clinical practice. The progress in surgical techniques and immunosuppression has broadened the spectrum of patients who can benefit from intestinal transplant, including both IIT and MVT. The expansion of indications offers hope to patients with complex gastrointestinal disorders. The detection of donor-specific antibodies in graft assessment advances diagnostic accuracy, ultimately improving patient outcomes.

Simultaneous Serial Transverse Enteroplasty (STEP) in Size Mismatch Small Bowel Transplantations

BACKGROUND

Small bowel transplantation (SBTX) in children receiving larger grafts from adults can be challenging because of size mismatch. The aim of the present study was to assess whether a simultaneous serial transverse enteroplasty (STEP) can address the problem of size mismatch.

METHODS

Three different size ratio groups between donors and recipients were compared in a porcine model with a 14-day follow-up. The groups were size matched, size mismatched (1:3.8 weight ratio), and size mismatched + STEP (each n = 8).

RESULTS

It was technically feasible to simultaneously perform a STEP and SBTX of a mismatched intestinal segment. The postoperative clinical course was uneventful. No signs of bleeding, leakage, stenosis, or ileus were observed and the intestinal segment was well perfused at relaparotomy. Body weight decreased in all groups, but the percentage decrease was lowest in the mismatched + STEP group. Vital enterocyte masses were similar in all the groups (citrulline levels) and the nutritional status was best in the STEP group (transferrin levels, p = 0.04).

CONCLUSIONS

We have demonstrated that a simultaneous STEP and SBTX procedure is technically feasible and clinically useful in overcoming the challenges associated with size mismatched SBTX. Our short-term findings justify further investigation in a larger series to elucidate the long-term outcomes of this procedure.

Nutritional Challenges in Patients After Intestinal Autotransplantation and Ex Vivo Surgery

BACKGROUND

Intestinal autotransplantation (IATx) and ex vivo resection is a novel surgical strategy to treat patients with unresectable abdominal neoplasms involving the mesenteric root. Nutritional challenges after IATx and ex vivo surgery have not been well described.

METHODS

Eleven patients, aged 7-68 years (median, 49 years) underwent IATx and ex vivo resection at our center from 2009 to 2016. A retrospective chart review was performed to evaluate nutrition status, tolerance of an oral diet, and need for parenteral nutrition (PN) and enteral (EN) nutrition. These factors were assessed preoperatively and at 3 months postoperatively.

RESULTS

Prior to surgery, 10 of 11 patients were tolerating oral diets without need for additional PN or EN. Postoperatively, PN was initiated in all patients from 1-15 days after surgery (median, 5 days) and continued from 12-122 days (median, 32.5 days), except for of 1 patient who underwent a total enterectomy and required subsequent allotransplantation with ongoing PN. EN was initiated in 9 patients from 4-117 days after surgery (median, 17 days) and has been ongoing in 5 patients. Oral diets were initiated in all patients from 5-115 days (median, 14 days) postoperatively; at 3 months, 11 of 12 patients were tolerating oral diets.

CONCLUSION

IATx and ex vivo resection presents a unique challenge with respect to nutrition management. Patients undergoing these complex surgeries may have difficulty maintaining adequate nutrition with an oral diet alone in the immediate postoperative period and beyond and may require prolonged nutrition support.

The optimal intestinal segment length for experimental size-mismatched intestinal transplantation: Defining the maximum length with the lowest blood flow needs in a porcine model

Transplanted Intestinal Segments (IS) must match the perfusion capacities of the recipient. This can be challenging during a size-mismatched SBTX. In this study, we defined the maximum IS length with lowest blood flow needs in a porcine model by evaluating the physiological perfusion rates of different IS lengths. Blood flow in the SMA, aorta segment four, and general circulatory parameters were monitored before and after sequential intestinal resection. IS lengths of 30 cm, 60 cm, 120 cm, and 300 cm (n = 8 each) were compared. The IS blood flow requirements increased with IS length (30 cm: 19.5 ± 3.4 mL/min; 60 cm: 16.9 ± 6.7 mL/min; 120 cm: 34.9 ± 8.5 mL/min; 300 cm: 62.9 ± 11.6 mL/min). Absolute IS blood flow (P = .004), percentage IS blood flow uptake from the SMA (P = .001), and percentage IS blood flow uptake from the aorta (P = .005) increased significantly between 60 cm and 120 cm. We concluded that 60 cm was the maximum IS length before blood flow demands significantly increased in a porcine model.

Diagnostic Lessons from a Complex Case of Postintestinal Transplantation Enteropathy

Recent advances in the field of intestinal transplantation have been mitigated by the incidence of allograft rejection. In such events, early identification and appropriate timing of antirejection therapy are crucial in retaining graft function. We present the case of a patient who suffered severe postintestinal transplantation allograft enteropathy, primarily characterized by extensive mucosal ulcerations, and was refractory to all conventional therapy. This progressed as chronic rejection; however crucially this was not definitively diagnosed until allograft function had irreversibly diminished. We argue that the difficulties encountered in this case can be attributed to the inability of our current array of investigative studies and diagnostic guidelines to provide adequate clinical guidance. This case illustrates the importance of developing reliable and specific markers for guiding the diagnosis of rejection and the use of antirejection therapeutics in this rapidly evolving field of transplant surgery.

Long-Term Outcomes of Intestinal and Multivisceral Transplantation at a Single Center in Argentina

BACKGROUND

Intestinal failure (IF) patients received parenteral nutrition (PN) as the only available therapy until intestinal transplantation (ITx) evolved as an accepted treatment. The aim of this article is to report the long-term outcomes of a series of ITx performed in pediatric and adult patients at a single center 9 years after its creation.

PATIENTS AND METHODS

This is a retrospective analysis of the ITx performed between May 2006 and January 2015. Diagnoses, pre-ITx mean time on PN, indications for ITx, time on the waiting list for types of ITx, mean total ischemia time, and warm ischemia time, time until PN discontinuation, incidence of acute and chronic rejection, and 5-year actuarial patient survival are reported.

RESULTS

A total of 42 patients received ITx; 80% had short gut syndrome (SG); the mean time on PN was 1620 days. The main indication for ITx was lack of central venous access followed by intestinal failure-associated liver disease (IFALD) and catheter-related infectious complications. The mean time on the waiting list was 188 days (standard deviation, ±183 days). ITx were performed in 26 children and 14 adults. In all, 32 procedures were isolated ITx (IITX); 10 were multiorgan Tx (MOT; 3 combined, 7 multivisceral Tx (MVTx), 1 modified MVTx and 2 with kidney); 2 (4.7 %) were retransplantations: 1 IITx, 1 MVTx, and 5 including the right colon. Thirteen patients (31%) received abdominal rectus fascia. All procedures were performed by the same surgical team. Total ischemia time was 7:53 ± 2:04 hours, and warm ischemia time was 40.2 ± 10.5 minutes. The mean length of implanted intestine was 325 ± 63 cm. Bishop-Koop ileostomy was performed in 67% of cases. In all, 16 of 42 Tx required early reoperations. The overall mean follow-up time was 41 ± 35.6 months. The mean time to PN discontinuation after Tx was 68 days (P = .001). The total number of acute cellular rejection (ACR) episodes until the last follow-up was 83; the total number of grafts lost due to ACR was 4; and the total graft lost due to chronic rejection was 3. At the time of writing, the overall 5-year patient survival is 55% (65% for IITx vs 22% for MOT; P = .0001); 60% for pediatric recipients vs 47% for adults (P = NS); 64% when the indication for ITx was SG vs 25% for non-SG (P = .002).

CONCLUSIONS

At this center, candidates with SG, in the absence of IFALD requiring IITx, showed the best long-term outcomes, independent of recipient age. A multidisciplinary approach is mandatory for the care of intestinal failure patients, to sustain a rehabilitation and transplantation program over time.

Intestinal and multivisceral transplantation

Intestinal transplantation has shown exceptional growth over the past 10 years. At the end of the 1990’s, intestinal transplantation moved out of the experimental realm to become a routine practice in treating patients with severe complications related to total parenteral nutrition and intestinal failure. In the last years, several centers reported an increasing improvement in survival outcomes (about 80%), during the first 12 months after surgery, but long-term survival is still a challenge. Several advances led to clinical application of transplants. Immunosuppression involved in intestinal and multivisceral transplantation was the biggest gain for this procedure in the past decade due to tacrolimus, and new inducing drugs, mono- and polyclonal anti-lymphocyte antibodies. Despite the advancement of rigid immunosuppression protocols, rejection is still very frequent in the first 12 months, and can result in long-term graft loss. The future of intestinal transplantation and multivisceral transplantation appears promising. The major challenge is early recognition of acute rejection in order to prevent graft loss, opportunistic infections associated to complications, post-transplant lymphoproliferative disease and graft versus host disease; and consequently, improve results in the long run.

Fifteen years' experience of intestinal and multivisceral transplantation in the Nordic countries

OBJECTIVE

Intestinal and multivisceral transplantation have gained acceptance as treatment modalities for patients with: intestinal failure and life-threatening complications of parenteral nutrition (PN), rare cases of vascular abdominal catastrophes and selected cases of low-grade neoplastic tumors such as neuroendocrine pancreatic tumors and desmoids involving the mesenteric root. The aim was to describe the survival and nutritional outcome in the transplanted Nordic patients and the complications attributed to this procedure.

METHOD

The authors included all Nordic patients transplanted between January 1998 and December 2013. Information on patients transplanted outside the Nordic region was collected through questionnaires.

RESULTS

A total of 34 patients received different types of intestinal allografts. Currently, there are two Nordic transplant centers (n = 29) performing these procedures (Gothenburg, Sweden n = 24, Helsinki, Finland n = 5). The remaining five patients were transplanted in the USA (n = 3) and the UK (n = 2). Most patients were transplanted for life-threatening failure of PN (70%) caused primarily by intestinal motility diseases (59%). Allograft rejection was the most common complication and occurred in 79% of the patients followed by post-transplantation lymphoproliferative disorders (21%) and graft-versus-host disease (18%). The 1- and 5-year survival was 79% and 65% respectively for the whole cohort and nutritional autonomy was achieved in 73% of the adults and 57% of the children at 1 year after transplantation.

CONCLUSION

This collective Nordic experience confirms that intestinal transplantation is a complex procedure with many complications, yet with the possibility to provide long-term survival in selected conditions previously considered untreatable.

Organ bioengineering for the newborn

Regenerative medicine has recently been established as an emerging interdisciplinary field focused on the repair; replacement or regeneration of cells, tissues and organs. It involves various disciplines, which are focused on different aspects of the regeneration process such as cell biology, gene therapy, bioengineering, material science and pharmacology. In this article, we will outline progress on tissue engineering of specific tissues and organs relevant to paediatric surgery.

Multivisceral transplantation: where do we stand?

Intestinal transplantation is the definitive therapy for patients with irreversible intestinal failure and can be combined with transplantation of other abdominal organs, such as stomach, spleen, and pancreas with or without liver. There is an increasing trend in the volume of intestinal and multivisceral transplantation in the past few decades and there is also increasing trend in patient and graft survival primarily due to improved patient selection, advances in immunosuppression, and improved perioperative management. This review summarizes the various key elements in patient selection, types of grafts, and updates in the perioperative management involved in multivisceral transplantation.

Liver, pancreas and small bowel transplantation: current ethical issues

We describe the medical state of the art in liver, pancreas and small bowel transplantation, and portray the ethical issues. Although most ethical questions related to these transplantations are not specific for liver, pancreas and small bowel, they do challenge ethical analysis as well as new policies and clinical procedures. Firstly, outcomes continue to be of utmost concern, as information is only limited available, is developing over time and is surrounded by many uncertainties. Secondly, characteristics of donors and recipients should be carefully evaluated. The question of what qualifies a donor and a recipient should be considered against the background of a quest for extended criteria, embracing marginal cases, and a judgment with regard to what counts as a good enough outcome. Thirdly, ethical principles of autonomy and fairness are pushed, given the circumstance of severe scarcity, towards limits that can easily be crossed.

Intestinal transplantation: review of operative techniques

The improvement of outcomes in intestinal transplantation (ITx) over the last two decades has been made possible through standardization in surgical techniques, improvements in immunosuppressive and induction protocols, and post-operative patient care. From a surgical technical point of view, all different types of small bowel containing transplants can be categorized into three main prototypes, including isolated small bowel, liver-small bowel, and multivisceral transplantations. In this review, we describe these three main prototypes and discuss the most important technical modifications of each type, as well as donor and recipient procedures, and highlight the more recent operative technical topics of discussion in the literature.

Survival of patients evaluated for intestinal and multivisceral transplantation - the Scandinavian experience

OBJECTIVE

The current treatment of choice for patients with intestinal failure is parenteral nutrition, whereas medical therapy or resection is preferred for patients with neuroendocrine pancreatic tumors (NEPT) along with liver metastasis. As the survival of patients undergoing intestinal and multivisceral transplantation is improving, the discussion for expansion of treatment options has become a subject of debate. The aim was to investigate the outcome for patients referred for intestinal and multivisceral transplantation and to determine which patient group are the ones most likely to benefit the most from transplantation.

METHODS

The authors included all patients evaluated for intestinal and multivisceral transplantation at the Sahlgrenska University Hospital and The Queen Silvia Children's Hospital center between February 1998 and November 2009. Patients were classified according to proposed treatment strategy, and the outcome was evaluated.

RESULTS

A total of 43 adults and 19 children with either intestinal failure or NEPT with liver metastases were evaluated for transplantation. Of these patients, 15 adults and 5 children were transplanted. Transplantation was lifesaving for most children - all the children survived after transplantation, but 70% (4/6) died while awaiting transplantation. Among the adult patients with intestinal failure, the survival rate for patients considered to be stable on parenteral nutrition was higher than the transplanted adult patients. The survival rate of patients with NEPT was similar to the results seen among patients transplanted for intestinal failure.

CONCLUSION

The results confirm the poor prognosis of patients with intestinal failure awaiting transplantation and indicate that different transplantation criteria may be applied for adults and children, especially when early transplantation is the preferred treatment. The role of multivisceral transplantation in patients with NEPT remains uncertain.

Cutaneous graft versus host disease in pediatric multivisceral transplantation

Multivisceral transplantation (MvTx) is the concurrent transplantation of the stomach, pancreaticoduodenal complex, and intestine, with or without the liver. Its use is increasing worldwide as it has been considered as a therapy for patients with functional disturbance of several organs. Graft-versus-host disease (GvHD) has been a relevant clinical problem in MvTx ever since the procedure was first performed, but little has been reported about its specific cutaneous features. Our study included all pediatric patients with clinical and histopathologic evidence of cutaneous GvHD who received MvTx between October 1999 and December 2010 in University Hospital La Paz. Seventeen children underwent MvTx at our center during this period of time. Five patients developed cutaneous GvHD (29.4%). The median onset was 45.2 days after transplantation. Acute cutaneous GvHD, consisting of symmetrical maculopapular exanthema with prominent acral erythema and accentuated lesions on the face and pinnae, was clinically suspected and pathologically confirmed in four patients (80%). Three children (60%) experienced disease progression to a formation and a positive Nikolsky sign. Only one girl (20%) showed lichenoid GvHD. The first therapeutic approach was steroids and tacrolimus adjustment; many other drugs were used in refractory cases. Three of the five patients (60%) died with concomitant GvHD, the immediate cause of death being another comorbid disease. Knowledge of the features of cutaneous GvHD in MvTx allows clinicians early recognition and prompt therapeutic intervention that may prevent progression to higher-grade disease and improve outcomes for these patients.

Post-transplant critical care outcomes for pediatric multivisceral and intestinal transplant patients

This study reviews the post-operative management of pediatric intestinal transplant patients at a single center with reporting of standard PICU benchmarks for quality of care. It is a retrospective, descriptive, chart review describing our institution's experience between 2006 and 2010. Twenty patients were included. Median age at transplant was 1.6 yr. Median length of PICU stay was 12 days. Median ventilation time was two days. Median time for continuous sedation infusion was two days, with median continuous pain medication infusion of three days. All patients were placed on parental nutrition and started on enteral feedings between days 3 and 4. Forty percent of patients required hemodynamic support. Only 35% of patients required insulin therapy. Diuretics were frequently used in this patient population. There were no episodes of early rejection. The survival rate to PICU discharge was 95%. Our institution's experience over the past four yr has been very successful with a short duration of mechanical ventilation, limited use of pain and sedation drips, early initiation of enteral feedings, minimal hemodynamic support, and a low mortality rate to PICU discharge despite a preponderance of complex MVTx recipients.

Small-Bowel Allograft Biopsies in the Management of Small-Intestinal and Multivisceral Transplant Recipients: Histopathologic Review and Clinical Correlations

Context.—Intestinal transplant has become a standard treatment option in the management of patients with irreversible intestinal failure. The histologic evaluation of small-bowel allograft biopsy specimens plays a central role in assessing the integrity of the graft. It is essential for the management of acute cellular and chronic rejection; detection of infections, particularly with respect to specific viruses (cytomegalovirus, adenovirus, Epstein-Barr virus); and immunosuppression-related lymphoproliferative disease.

Objective.—To provide a comprehensive review of the literature and illustrate key histologic findings in small-bowel biopsy specimen evaluation of patients with small-bowel or multivisceral transplants.

Data Sources.—Literature review using PubMed (US National Library of Medicine) and data obtained from national and international transplant registries in addition to case material at Columbia University, Presbyterian Hospital, and Mount Sinai Medical Center, New York, New York.

Conclusions.—Key to the success of small-bowel transplantation and multivisceral transplantation are the close monitoring and appropriate clinical management of patients in the posttransplant period, requiring coordinated input from all members of the transplant team with the integration of clinical, laboratory, and histopathologic parameters.

Short bowel syndrome in children: current and potential therapies

Short bowel syndrome (SBS) reflects a state of malabsorption that occurs due to loss of a significant portion of the small bowel. The pathophysiology of SBS is determined largely by the process of adaptation, which is the innate attempt by the remnant portions of the intestine to increase fluid and nutrient reabsorption. In recent years, emphasis has been placed on intestinal rehabilitation with multidisciplinary teams as a comprehensive approach to the management of patients with SBS. In our institution, the multidisciplinary team members include pediatric gastroenterologists, pediatric surgeons, pediatric dieticians, physical therapists, occupational therapists, neonatologists (especially for patients still under their care), transplant surgeons, transplant coordinators and social workers. Parenteral nutrition plays a significant role in the management of SBS, but its use is associated with many potential complications, including cholestatic liver disease. Fish oil-based lipid emulsions have shown promise in their ability to reverse and also prevent the development of cholestasis in these patients. Clinical trials have shown that growth factors and other trophic hormones facilitate the process of adaptation. The most significant impact has been shown with the use of glucagon-like peptide-2 and its analog (teduglutide). Surgical interventions remain an important part of the management of SBS to facilitate adaptation and treat complications. Intestinal transplantation is a last resort option when the process of adaptation is unsuccessful. This review article is intended to provide an overview of the conventional and emerging therapies for pediatric SBS.

A rat decellularized small bowel scaffold that preserves villus-crypt architecture for intestinal regeneration

Management of intestinal failure remains a clinical challenge and total parenteral nutrition, intestinal elongation and/or transplantation are partial solutions. In this study, using a detergent-enzymatic treatment (DET), we optimize in rats a new protocol that creates a natural intestinal scaffold, as a base for developing functional intestinal tissue. After 1 cycle of DET, histological examination and SEM and TEM analyses showed removal of cellular elements with preservation of the native architecture and connective tissue components. Maintenance of biomechanical, adhesion and angiogenic properties were also demonstrated strengthen the idea that matrices obtained using DET may represent a valid support for intestinal regeneration.

Complications of enterocutaneous fistulas and their management

Complications related to enterocutaneous fistulas are common and include sepsis, malnutrition, and fluid or electrolyte abnormalities. Intestinal failure is one of the most feared complications of enterocutaneous fistula management and results in significant patient morbidity and mortality. The authors review emerging trends in the medical and surgical management of patients with intestinal failure.

Psychiatric issues in pediatric organ transplantation

Solid organ transplantation has become the first line of treatment for a growing number of life-threatening pediatric illnesses. With improved survival, research into the long-term outcome of transplant recipients has become important to clinicians. Adherence to medical instructions remains a challenge, particularly in the adolescent population. New immunosuppressant approaches promise to expand organ transplantation in additional directions. Extension of transplantation into replacement of organs such as faces and hands raises complex ethical issues.

[Small intestine, pancreas and islet cell transplantation]

The past decade has seen substantial improvements in patient and graft survival after intestinal transplantation. This improvement has been achieved by advances in donor and recipient selection, patient management, immunosuppression and surgical techniques. Intestinal transplantation is therefore considered a therapeutic option in the treatment of short bowel syndrome. Mile stones include the development of the calcineurin inhibitor Tacrolimus for immunosuppression as well as induction therapy using immune modulating substances like interleukin-2 receptor antagonists and antilymphocyte preparations. In addition to improvements in immunosuppression, antimicrobial prophylaxis and diagnosis of rejection, advances in surgical techniques have been crucial to achieving increased graft survival. Pancreas transplantation, generally with simultaneous kidney transplantation, is now available as a treatment option for patients with labile diabetes mellitus (usually type 1). Allogeneic islet transplantation was developed in the 1990s as a minimally invasive alternative to pancreas transplantation. Pancreatic islets are isolated enzymatically from the donor pancreas, in most cases infused into the portal vein and thus engrafted into the liver. Currently, technical and medical problems as well as high costs prevent the application of islet transplantation as a therapeutic option for a larger number of patients with diabetes mellitus.

Perioperative infliximab application ameliorates acute rejection associated inflammation after intestinal transplantation

As we have shown in the past, acute rejection-related TNF-α upregulation in resident macrophages in the tunica muscularis after small bowel transplantation (SBTx) results in local amplification of inflammation, decisively contributing to graft dysmotility. Therefore, the aim of this study is to investigate the effectiveness of the chimeric-monoclonal-anti-TNF-α antibody infliximab as perioperative single shot treatment addressing inflammatory processes during acute rejection early after transplantation. Orthotopic, isogenic and allogenic SBTx was performed in rats (BN-Lewis/BN-BN) with infliximab treatment. Vehicle and IV-immunoglobulin-treated animals served as controls. Animals were sacrificed after 24 and 168 h. Leukocyte infiltration was investigated in muscularis whole mounts by immunohistochemistry, mediator mRNA expression by Real-Time-RT-PCR, apoptosis by TUNEL and smooth muscle contractility in a standard organ bath. Both, infliximab and Sandoglobulin® revealed antiinflammatory effects. Infliximab resulted in significantly less leukocyte infiltration compared to allogenic controls and IV-immunoglobulin, which was accompanied by lower gene expression of MCP-1 (24 h), IFN-γ (168 h) and infiltration of CD8-positive cells. Smooth muscle contractility improved significantly after 24 h compared to all controls in infliximab treated animals accompanied by lower iNOS expression. Perioperative treatment with infliximab is a possible pharmaceutical approach to overcome graft dysmotility early after SBTx.

Lymphocyte depletion and repopulation in peripheral blood and small intestine of cynomolgus monkeys after alemtuzumab treatment

BACKGROUND

Alemtuzumab has been used as an induction agent in organ transplantation over 10 years, but the effect of alemtuzumab on lymphocytes in small intestine was not clear. We investigate lymphocyte depletion and repopulation phenomena both in peripheral blood and small intestine of cynomolgus monkeys, to assess the model using in preclinical transplantation.

MATERIALS AND METHODS

Monkeys without CD52 antigen on erythrocytes were selected. Lymphocyte depletion and repopulation was documented by flow cytometry. Sections of ileum were obtained for isolation of intestinal intraepithelial lymphocytes (IEL) and lamina propria lymphocytes (LPL), and also for immunofluorescence examination.

RESULTS

Powerful depletion of lymphocytes (>80%) from blood followed by gradual repopulation was observed. CD20(+) B cells, CD8(+) T cells, CD4(+) T cells returned to pretreatment levels by d 21, 35, 56. IEL, LPL reduced by 70%, 72% on d 9, recovered to 59%, 57% of pretreatment levels by d 35, and were completed by d 56. Depletion and repopulation of IEL and LPL were confirmed by immunofluorescence.

CONCLUSIONS

Depletion of lymphocytes in peripheral blood was less powerful and repopulation occurred faster than in patients. The lymphocyte depletion and repopulation occurred in small intestine. This model can be used in preclinical transplantation.

Psychiatric issues in pediatric organ transplantation

Solid organ transplantation has become the first line of treatment for a growing number of life-threatening pediatric illnesses. With improved survival, research into the long-term outcome of transplant recipients has become important to clinicians. Adherence to medical instructions remains a challenge, particularly in the adolescent population. New immunosuppressant approaches promise to expand organ transplantation in additional directions. Extension of transplantation into replacement of organs such as faces and hands raises complex ethical issues.