Lessons learned in pediatric small bowel and liver transplantation from living-related donors. Transplantation. 2009;87:1027-1030. [PMID: 19352122 DOI: 10.1097/tp.0b013e31819cc3bf]

Outcome After Intestinal Transplantation From Living Versus Deceased Donors: A Propensity-matched Cohort Analysis of the International Intestinal Transplant Registry

OBJECTIVE

To describe the worldwide experience with living donation (LD) in intestinal transplantation (ITx) and compare short-term and long-term outcomes to a propensity-matched cohort of deceased donors.

BACKGROUND

ITx is a rare life-saving procedure for patients with complicated intestinal failure (IF). Living donation (LD)-ITx has been performed with success, but no direct comparison with deceased donation (DD) has been performed. The Intestinal Transplant Registry (ITR) was created in 1985 by the Intestinal Transplant Association to capture the worldwide activity and promote center's collaborations.

METHODS

Based on the ITR, 4156 ITx were performed between January 1987 and April 2019, of which 76 (1.8%) were LD, including 5 combined liver-ITx, 7 ITx-colon, and 64 isolated ITx. They were matched with 186 DD-ITx for recipient age/sex, weight, region, IF-cause, retransplant, pretransplant status, ABO compatibility, immunosuppression, and transplant date. Primary endpoints were acute rejection and 1-/5-year patient/graft survival.

RESULTS

Most LDs were performed in North America (61%), followed by Asia (29%). The mean recipient age was: 22 years; body mass index: 19kg/m²; and female/male ratio: 1/1.4. Volvulus (N=17) and ischemia (N=17) were the most frequent IF-causes. Fifty-two percent of patients were at home at the time of transplant. One-/5-year patient survival for LD and DD was 74.2/49.8% versus 80.3/48.1%, respectively ( P =0.826). One-/5-year graft survival was 60.3/40.6% versus 69.2/36.1%, respectively ( P =0.956). Acute rejection was diagnosed in 47% of LD versus 51% of DD ( P =0.723).

CONCLUSION

Worldwide, LD-ITx has been rarely performed. This retrospective matched ITR analysis revealed no difference in rejection and in patient/graft survival between LD and DD-ITx.

25 Years of a Standardized Technique for Living Donor Intestinal Transplantation: A Systematic Review

A safe, reproducible and standardized surgical technique for intestinal procurement and transplantation from a living donor (LD) was introduced in 1997 and has been used in the majority of cases since. The key principles are: 1. procurement of 180-200 cm of distal ileum in adults (about 60-150 cm in pediatric recipients depending on age and weight) on a vascular pedicle comprising the LD ileocolic vessels or terminal branches of the superior mesenteric vessels, 2. the terminal ileum (30-40 cm of the most distal ileum), the ileocecal valve and the cecum remain with the donor to not interfere with B12-absorption and bowel transit time, 3. systemic venous drainage with anastomoses between the LD ileocolic vessels and the recipient's infrarenal aorta and vena cava, and 4. restoration of recipient bowel continuity through proximal anastomosis and distal graft ileostomy for biopsy access and graft monitoring. Recipients of a successful LD intestinal transplant become total parenteral nutrition (TPN)-independent within a few weeks posttransplant. LD vs deceased donor (DD) intestinal transplants can be performed in a more timely fashion. Hence, LD (in contrast to DD) intestinal transplants are also pre-emptive procedures in patients with advanced, but still reversible, TPN-induced liver disease and help reduce the wait-list mortality for combined DD intestinal and liver transplants. Life-saving combined LD intestinal and liver transplants, albeit rare, have also been successfully performed either simultaneously or subsequently. There have been no reported deaths or major complications of living intestinal donors. A better metabolic profile has been reported in some donors post-donation. In total, 85 documented LD intestinal transplants have been performed worldwide at over 20 different transplant centers in 12 different countries. In about 70 transplants, the standardized technique was used. There has been no difference in outcome between LD vs DD intestinal transplants. Long-term studies have shown that > 10 year of graft function is not uncommon. Since the introduction of the standardized surgical technique, LD intestinal transplantation has evolved from an experimental to an established and standardized procedure.

3D Bioprinting Strategies for the Regeneration of Functional Tubular Tissues and Organs

It is difficult to fabricate tubular-shaped tissues and organs (e.g., trachea, blood vessel, and esophagus tissue) with traditional biofabrication techniques (e.g., electrospinning, cell-sheet engineering, and mold-casting) because these have complicated multiple processes. In addition, the tubular-shaped tissues and organs have their own design with target-specific mechanical and biological properties. Therefore, the customized geometrical and physiological environment is required as one of the most critical factors for functional tissue regeneration. 3D bioprinting technology has been receiving attention for the fabrication of patient-tailored and complex-shaped free-form architecture with high reproducibility and versatility. Printable biocomposite inks that can facilitate to build tissue constructs with polymeric frameworks and biochemical microenvironmental cues are also being actively developed for the reconstruction of functional tissue. In this review, we delineated the state-of-the-art of 3D bioprinting techniques specifically for tubular tissue and organ regeneration. In addition, this review described biocomposite inks, such as natural and synthetic polymers. Several described engineering approaches using 3D bioprinting techniques and biocomposite inks may offer beneficial characteristics for the physiological mimicry of human tubular tissues and organs.

Update on Chronic Rejection After Intestinal Transplant: An Overview From Experimental Settings to Clinical Outcomes

Chronic rejection affects the long-term survival of solid-organ transplants, accounting for an incidence of between 5% and 10% after intestinal/multivisceral transplant. Because of unclear symptoms and signs and endoscopic findings, the diagnosis is often delayed. Presently, allograft removal represents the only available therapy due to the absence of effective pharmacologic approaches. Extensive research, through animal models, has been performed over the past 20 years to clarify the complex immune- and nonimmune-mediated mechanisms behind the development of chronic allograft enteropathy, with the aim of elucidating how to avert chronic rejection. The role of donor-specific antibodies and the way to challenge them in the clinic have gained acceptance among transplant centers as one of the main steps to prevent chronic rejection, although no common protocol exists that can be applied in a systematic fashion. The adjunct of a liver graft when retrans planting is needed in a sensitized recipient due to its protective effect against humoral immunity. Multicenter studies and clinical trials are required to better understand the pathogenesis of chronic rejection and to find the therapeutic answer to this clinical query.

Landscape of Living Multiorgan Donation in the United States: A Registry-Based Cohort Study

BACKGROUND

The donation of multiple allografts from a single living donor is a rare practice, and the patient characteristics and outcomes associated with these procedures are not well described.

METHODS

Using the Scientific Registry of Transplant Recipients, we identified 101 living multiorgan donors and their 133 recipients.

RESULTS

The 49 sequential (donations during separate procedures) multiorgan donors provided grafts to 81 recipients: 21 kidney-then-liver, 15 liver-then-kidney, 5 lung-then-kidney, 3 liver-then-intestine, 3 kidney-then-pancreas, 1 lung-then-liver, and 1 pancreas-then-kidney. Of these donors, 38% donated 2 grafts to the same recipient and 15% donated 2 grafts as non-directed donors. Compared to recipients from first-time, single organ living donors, recipients from second-time living donors had similar graft and patient survival. The 52 simultaneous (multiple donations during one procedure) multiorgan donors provided 2 grafts to 1 recipient each: 48 kidney-pancreas and 4 liver-intestine. Donors had median of 13.4 years (interquartile range, 8.3-18.5 years) of follow-up. There was one reported death of a sequential donor (2.5 years after second donation). Few postdonation complications were reported over a median of 116 days (interquartile range, 0-295 days) of follow-up; however, routine living donor follow-up data were sparse. Recipients of kidneys from second-time living donors had similar graft (P = 0.2) and patient survival (P = 0.4) when compared with recipients from first-time living donors. Similarly, recipients of livers from second-time living donors had similar graft survival (P = 0.9) and patient survival (P = 0.7) when compared with recipients from first-time living donors.

CONCLUSIONS

Careful documentation of outcomes is needed to ensure ethical practices in selection, informed consent, and postdonation care of this unique donor community.

Living Donor Intestinal Transplantation

Living donor intestinal transplantation (LDIT) has been improved leading to results comparable to those obtained with deceased donors. LDIT should be limited to specific indications and patient selection. The best indication is combined living donor intestinal/liver transplantation in pediatric recipients with intestinal and hepatic failure; the virtual elimination of waiting time may avoid the high mortality experienced by candidates on the deceased waiting list. Potentially, LDIT could be used in highly sensitized recipients to allow the application of de-sensitization protocols. In the case of available identical twins or HLA-identical sibling, LDIT has a significant immunologic advantage and should be offered.

Chronic Rejection After Intestinal Transplant: Where Are We in Order to Avert It?

Chronic rejection affects the long-term survival of all solid organ transplants and, among intestinal allografts, occurs in up to 10% of the recipients. The insidious clinical evolution of the chronic allograft enteropathy, the absence of noninvasive biomarkers, and the late endoscopic findings delay its diagnosis. No pharmacological approach has been proven effective, and allograft removal nowadays still represents the only available therapy. The inclusion of the liver in the visceral allograft appears to be the only intervention affecting the development of chronic rejection, as revealed by large-center studies and registry reports. A significant body of evidence emerged from the experimental setting and provided essential knowledge on the complex mechanisms behind the development of chronic allograft enteropathy. More recently, donor-specific antibodies have been suggested as an early, key element in the natural history of chronic allograft enteropathy and several novel approaches, tackling the antibody-mediated graft injury, have gained acceptance in clinical settings and are believed to impact on chronic rejection. The inclusion of a liver allograft is advocated when re-transplanting a sensitized recipient, due to its protective effect against humoral immunity. Multicenter trials are required to understand and tackle chronic rejection, and find the therapeutic answer to this clinical dilemma.

Advances in small bowel transplantation

Small bowel transplantation is a life-saving surgery for patients with intestinal failure. The biggest problem in intestinal transplantation is graft rejection. Graft rejection is the main reason for morbidity and mortality. Rejection has a negative effect on the survival of the graft. While 50%-75% of small bowel transplantation patients experience acute rejection, chronic rejection occurs in approximately 15% of patients. Immune monitoring is crucial after small bowel transplantation. Unlike other types of transplantation, there are no non-invasive or reliable markers to predict rejection in small bowel transplantation. The diagnosis of AR is confirmed by clinical symptoms, endoscopic appearance, and pathological specimens taken by endoscopy. Thus, histopathological examinations obtained by protocol biopsies remain as the gold standard for intestinal graft monitoring; however, biopsies have some complications, especially in small grafts. In addition to the high complication rate, biopsies are non-diagnostic; thus, multiple biopsies should be performed to exclude rejection. Therefore, auxiliary assays, such as measurements of citrulline and calprotectin in the blood, cytofluorographic examination of peripheral blood immune cells, cytokine profiling, and distinct gene-set-change measurements, are increasingly being used in small bowel transplantation. Developments in the understanding of genes seem to be promising that limited gene sets, taken from blood or from intestinal biopsies, will enhance pathological diagnosis. Bone marrow mesenchymal stem cell transplantation with SBT and tissue engineering are also promising procedures.

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.

Intestinal transplantation

Intestinal transplantation has now emerged as a lifesaving therapeutic option and standard of care for patients with irreversible intestinal failure. Improvement in survival over the years has justified expansion of the indications for intestinal transplantation beyond the original indications approved by Center for Medicare and Medicaid services. Management of patients with intestinal failure is complex and requires a multidisciplinary approach to accurately select candidates who would benefit from rehabilitation versus transplantation. Significant strides have been made in patient and graft survival with several advancements in the perioperative management through timely referral, improved patient selection, refinement in the surgical techniques and better understanding of the immunopathology of intestinal transplantation. The therapeutic efficacy of the procedure is well evident from continuous improvements in functional status, quality of life and cost-effectiveness of the procedure. This current review summarizes various aspects including current practices and evidence based recommendations of intestinal transplantation.

Intestinal Transplantation from Living Donors

Intestinal transplantation (ITx) represents the physiologic alternative to total parenteral nutrition (TPN) for patients suffering from life-threatening complications of irreversible intestinal failure. The number of transplants performed worldwide has been increasing for several years until recently. ITx has recently become a valid therapeutic option with a graft survival rate between 80 % and 90 % at 1 year, in experienced centers. These results have been achieved due to a combination of several factors: better understanding of the pathophysiology of intestinal graft, improved immunosuppression techniques, more efficient strategies for the monitoring of the bowel graft, as well as control of infectious complications and posttransplant lymphoproliferative disease (PTLD). In fact, this procedure is associated with a relatively high rate of complications, such as infections, acute rejection, graft versus host disease (GVHD), and PTLD, if compared to the transplantation of other organs. These complications may be, at least in part, the consequence of the peculiarity of this graft, which contains gut-associated lymphoid tissue and potentially pathogenic enteric flora. Furthermore, in these patients, the existing disease and the relative malnutrition could predispose them to infectious complications. Additionally, other factors associated with the procedure, such as laparotomy, preservation injury, abnormal motility, and lymphatic disruption, could all be implicated in the development of complications.

Use of tissue expansion to facilitate liver and small bowel transplant in young children with contracted abdominal cavities

Liver and small bowel transplant is an established treatment for infants with IFALD. Despite organ reduction techniques, mortality on the waiting list remains high due to shortage of size-matched pediatric donors. Small abdominal cavity volume due to previous intestinal resection poses a significant challenge to achieve abdominal closure post-transplant. Seven children underwent tissue expansion of abdominal skin prior to multiorgan transplant. In total, 17 tissue expanders were placed subcutaneously in seven children. All seven subjects underwent re-exploration to deal with complications: hematoma, extrusion, infection, or port related. Three expanders had to be removed. Four children went on to have successful combined liver and small bowel transplant. Two children died on the waiting list of causes not related to the expander and one child died from sepsis attributed to an infected expander. Tissue expansion can generate skin to facilitate closure of abdomen post-transplant, thus allowing infants with small abdominal volumes to be considered for transplant surgery. Tissue expansion in children with end-stage liver disease and portal hypertension is associated with a very high complication rate and needs to be closely monitored during the expansion process.

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.

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.

Long-term follow-up in adult living donors for combined liver/bowel transplant in pediatric recipients: a single center experience

Pediatric candidates for combined liver/bowel transplant (LBTx) experience a very high mortality on the cadaver waiting list. Our transplant center has successfully used adult living donors to treat pediatric candidates for LBTx. We report the long-term follow-up of this unique cohort of organ donors. The charts of six adult donors for LBTx performed between 2004 and 2007 were reviewed. All the pertinent clinical data were carefully reviewed and integrated with phone interviews of all donors. A total of six children (average age 13.5 months) received living donor LBTx. Average follow-up for the donors was 42 months (range 29-51). The donors' median age was 25 yr (19-32); five women and one man. The average median hospital stay was nine days. There were no peri-operative complications. At present all donors remain in good health. Three of the five mothers became pregnant after donation. Five of the six children are currently alive and well whereas one died with functioning grafts six months post-transplant due to plasmoblastic lymphoma. Living donor LBTx is an effective therapy for combined hepatic and intestinal failure in children less than five yr. The donor operation can be performed with minimal morbidity.

Current status of living donor small bowel transplantation

PURPOSE OF REVIEW

To analyze the current status of living donor intestinal transplantation (LDIT) as a treatment option for intestinal failure.

RECENT FINDINGS

Long-term outcomes from LDIT and combined living donor intestinal/liver transplantation (CLDILT) are comparable with those from transplantation using deceased donors. In certain life-threatening situations, especially in pediatric patients, this strategy may offer potential advantages.

SUMMARY

According United Network for Organ Sharing (UNOS) data children with intestinal failure affected by liver disease secondary to parenteral nutrition have the highest mortality on a waiting list compared with all candidates for solid organ transplantation. Elective nature of CLDILT offers multiple advantages for this patient population. LDIT also could be life-saving option for patients with intestinal failure who run out of venous access. Optimal timing, short ischemia time and good human leukocyte antigen (HLA) matching may contribute to lower postoperative complications. Current literature suggests that living intestinal donors experience very low morbidity and high level of satisfaction.

Intestinal transplantation: current outcomes and opportunities

PURPOSE OF REVIEW

This review highlights current outcomes in intestinal transplantation and summarizes advances that have recently occurred in five interrelated areas: progress in intestinal rehabilitation, immunologic and technical modifications, awareness of opportunities for improved allograft monitoring, and better assessment of long-term complications and morbidities.

RECENT FINDINGS

Improved long-term management of patients with intestinal failure as well as improved outcomes with intestine transplant are changing the previously established paradigms of timing for referral. For those requiring transplant, use of monoclonal and polyclonal antibody induction protocols have been associated with improved outcomes. Experience at centers of excellence demonstrates 1 and 5 year patient survival rates of 93 and 78%, respectively with ongoing investigations focusing on lowering long-term causes of graft loss such as chronic rejection or morbidities such as renal dysfunction. Descriptions of tissue, proteomic and genomic technologies to complement traditional methodologies to monitor graft function are emerging.

SUMMARY

Optimal timing for referral of children with intestinal failure and improved medical and surgical therapies increase the opportunity for intestinal adaptation without the need for transplant. For those undergoing transplant, technical and immunologic modifications, developments in graft monitoring, and reduction of long-term morbidities are leading to improved outcomes.