Intestinal transplantation in composite visceral grafts or alone

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.

Ileostomy After Intestinal Transplantation: The First in Depth Report on Techniques, Complications, and Outcomes

BACKGROUND

Temporary ileostomy during intestinal transplantation (ITx) is the standard technique for allograft monitoring. A detailed analysis of the ITx ileostomy has never been reported.

METHODS

A retrospective review of a single-center ITx database was performed. The analysis was divided into ileostomy formation and takedown episodes.

RESULTS

One hundred thirty-five grafts underwent ileostomy formation, and 79 underwent ileostomy takedown. Median age at ITx was 7.7 years and weight was 23 kg. Allograft types were intestine (22%), liver/intestine (55%), multivisceral (16%), and modified multivisceral (7%). Sixty-four percent had 1-stage ITx, whereas 36% required 2-staged ITx. Final ileostomy types were end (20%), loop (10%), distal blowhole (59%), and proximal blowhole (11%). Ileostomy formation: Thirty-one grafts had complications (23%), including prolapse (26%), ischemia (16%), and parastomal hernia (19%). Twelve required surgical revision. There were no significant differences in graft type, ileostomy type, survival, and ileostomy takedown rate between grafts with and without complications. Colon inclusive grafts had higher complication rates (P = 0.002). Ileostomy takedown: Ileostomy takedown occurred at a median of 422 days post-ITx. Twenty-five complications occurred after 22 takedowns (28%), including small bowel obstruction (27%) and abscess (18%). Fifteen grafts required surgical correction. Recipients with complications had longer hospital stay (17 versus 9 d; P = 0.001) than those without complications. Graft type, ileostomy type, and survival were not different.

CONCLUSIONS

The first of its kind analysis of the surgical ileostomy after ITx reveals that most recipients can undergo successful ileostomy formation/takedown, complication rates are significant but within an acceptable range, and complications do not affect survival. This study demonstrates that the routine use of transplant ostomies remains an acceptable practice after ITx. However, true analysis of risk and benefit will require a randomized control trial.

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.

Composite and Multivisceral Transplantation: Nomenclature, Surgical Techniques, Current Practice, and Long-term Outcome

The successful development of multivisceral and composite visceral transplantation is among the milestones in the recent history of human organ transplantation. All types of gastrointestinal transplantation have evolved to be the standard of care for patients with gut failure and complex abdominal pathologic conditions. The outcome has markedly improved over the last 3 decades owing to technical innovation, novel immunosuppression, and better postoperative care. Recent data documented significant improvement in the long-term therapeutic indices of all types of visceral transplantation close to that achieved with thoracic and solid abdominal organs.

Composite and Multivisceral Transplantation: Nomenclature, Surgical Techniques, Current Practice, and Long-term Outcome

The successful development of multivisceral and composite visceral transplantation is among the milestones in the recent history of human organ transplantation. All types of gastrointestinal transplantation have evolved to be the standard of care for patients with gut failure and complex abdominal pathologic conditions. The outcome has markedly improved over the last 3 decades owing to technical innovation, novel immunosuppression, and better postoperative care. Recent data documented significant improvement in the long-term therapeutic indices of all types of visceral transplantation close to that achieved with thoracic and solid abdominal organs.

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.

Liver and Kidney Transplantation: A Half-Century Historical Perspective

This article describes the evolution of solid organ kidney and liver transplantation and expounds on the challenges and successes that the early transplant researchers and clinicians encountered. The article highlights the surgical pioneers, delves into the milestones of enhanced immunosuppression protocols, discusses key federal legislative and policy changes, and expounds on the ongoing disparities of organ supply and demand and the need for extended criteria and live donor organs to combat these shortages. Finally, recent changes in organ allocation and distribution policies are discussed. The authors also spotlight novel interventions that will further revolutionize abdominal transplantation in the next 50 years.

The concept of gut rehabilitation and the future of visceral transplantation

In the 1990s, the introduction of visceral transplantation fuelled interest in other innovative therapeutic modalities for gut rehabilitation. Ethanol lock and omega-3 lipid formulations were introduced to reduce the risks associated with total parenteral nutrition (TPN). Autologous surgical reconstruction and bowel lengthening have been increasingly utilized for patients with complex abdominal pathology and short-bowel syndrome. Glucagon-like peptide 2 analogue, along with growth hormone, are available to enhance gut adaptation and achieve nutritional autonomy. Intestinal transplantation continues to be limited to a rescue therapy for patients with TPN failure. Nonetheless, survival outcomes have substantially improved with advances in surgical techniques, immunosuppressive strategies and postoperative management. Furthermore, both nutritional autonomy and quality of life can be restored for more than two decades in most survivors, with social support and inclusion of the liver being favourable predictors of long-term outcome. One of the current challenges is the discovery of biomarkers to diagnose early rejection and further improve liver-free allograft survival. Currently, chronic rejection with persistence of preformed and development of de novo donor-specific antibodies is a major barrier to long-term graft function; this issue might be overcome with innovative immunological and tolerogenic strategies. This Review discusses advances in the field of gut rehabilitation, including intestinal transplantation, and highlights future challenges. With the growing interest in individualized medicine and the value of health care, a novel management algorithm is proposed to optimize patient care through an integrated multidisciplinary team approach.

Five hundred intestinal and multivisceral transplantations at a single center: major advances with new challenges

OBJECTIVE

To assess the evolution of visceral transplantation in the milieu of surgical technical modifications, new immunosuppressive protocols, and other management strategies.

SUMMARY BACKGROUND DATA

With the clinical feasibility of intestinal and multivisceral transplantation in 1990, multifaceted innovative tactics were required to improve outcome and increase procedural practicality.

METHODS

Divided into 3 eras, 453 patients received 500 visceral transplants. The primary used immunosuppression was tacrolimus-steroid-only during Era I (5/90–5/94), adjunct induction with multiple drug therapy during Era II (1/95–6/01), and recipient pretreatment with tacrolimus monotherapy during Era III (7/01–11/08). During Era II/III, donor bone marrow was given (n = 79), intestine was ex vivo irradiated (n = 44), and Epstein-Barr-Virus (EBV)/cytomegalovirus (CMV) loads were monitored.

RESULTS

Actuarial patient survival was 85% at 1-year, 61% at 5-years, 42% at 10-years, and 35% at 15-years with respective graft survival of 80%, 50%, 33%, and 29%. With a 10% retransplantation rate, second/third graft survival was 69% at 1-year and 47% at 5-years. The best outcome was with intestine-liver allografts. Era III rabbit antithymocyte globulin or alemtuzumab pretreatment-based strategy was associated with significant (P < 0.0001) improvement in outcome with 1- and 5-year patient survival of 92% and 70%.

CONCLUSION

Survival has greatly improved over time as management strategies evolved. The current results clearly justify elevating the procedure level to that of other abdominal organs with the privilege to permanently reside in a respected place in the surgical armamentarium. Meanwhile, innovative tactics are still required to conquer long-term hazards of chronic rejection of liver-free allografts and infection of multivisceral recipients.

Themes of liver transplantation

Liver transplantation was the product of five interlocking themes. These began in 1958-1959 with canine studies of then theoretical hepatotrophic molecules in portal venous blood (Theme I) and with the contemporaneous parallel development of liver and multivisceral transplant models (Theme II). Further Theme I investigations showed that insulin was the principal, although not the only, portal hepatotrophic factor. In addition to resolving long-standing controversies about the pathophysiology of portacaval shunt, the hepatotrophic studies blazed new trails in the regulation of liver size, function, and regeneration. They also targeted inborn metabolic errors (e.g., familial hyperlipoproteinemia) whose palliation by portal diversion presaged definitive correction with liver replacement. Clinical use of the Theme II transplant models depended on multiple drug immunosuppression (Theme III, Immunology), guided by an empirical algorithm of pattern recognition and therapeutic response. Successful liver replacement was first accomplished in 1967 with azathioprine, prednisone, and antilymphoid globulin. With this regimen, the world's longest surviving liver recipient is now 40 years postoperative. Incremental improvements in survival outcome occurred (Theme IV) when azathioprine was replaced by cyclosporine (1979), which was replaced in turn by tacrolimus (1989). However, the biologic meaning of alloengraftment remained enigmatic until multilineage donor leukocyte microchimerism was discovered in 1992 in long-surviving organ recipients. Seminal mechanisms were then identified (clonal exhaustion-deletion and immune ignorance) that linked organ engraftment and the acquired tolerance of bone marrow transplantation and eventually clarified the relationship of transplantation immunology to the immunology of infections, neoplasms, and autoimmune disorders. With this insight, better strategies of immunosuppression have evolved. As liver and other kinds of organ transplantation became accepted as healthcare standards, the ethical, legal, equity, and the other humanism issues of Theme V have been resolved less conclusively than the medical-scientific problems of Themes I-IV.

Lymphoproliferative disorders and de novo malignancies in intestinal and multivisceral recipients: improved outcomes with new outlooks

BACKGROUND

Early experience with intestinal and multivisceral transplantation was plagued with high risk of rejection and posttransplant lymphoproliferative disorders (PTLD). To improve outcome, innovative management and immunosuppressant strategies were sequentially evolved.

METHODS

With initiation of the program in 1990, serial monitoring of Epstein-Barr-Viral load was introduced in 1994 with adoption of preemptive antiviral therapy. In 1995, cyclophosphamide or daclizumab induction was added to the tacrolimus-steroid-based multiple drug immunosuppressions. Such a conventional approach was replaced in 2001 with a novel immunosuppressive protocol consisting of recipient pretreatment with a single dose of rabbit antithymocyte globulin or alemtuzumab and posttransplant tacrolimus monotherapy.

RESULTS

With a total of 395 consecutive primary recipients, de novo malignancy(s) developed in 61 (15%) patients, with PTLD in 52 (13%), and nonlymphoid cancer (NLC) in 13 (3.2%). Malignancy was donor driven in 3 (4.6%) recipients and associated with graft-versus-host disease in 7 (11.4%). Children were at a significantly higher risk (P<0.001) of PTLD, and adults were more vulnerable (P=0.01) to NLC. With multivariate analyses, type of immunosuppression, recipient age, splenectomy, and treatment of rejection were significant PTLD risk factors.

CONCLUSIONS

Despite pretransplant lymphoid depletion, preemptive antiviral therapy and minimization of posttransplant immunosuppression significantly reduced PTLD morbidity (P=0.0001) and mortality (P=0.001) with no impact on NLC. Patient survival was also improved (P=0.0001) with 91% at 1 year and 75% at 5 years.

Technical refinements in small bowel transplantation

PURPOSE OF REVIEW

This review focuses on the recently described or revised refinements or innovations in small bowel transplantation.

RECENT FINDINGS

Changes in donor selection criteria; cadaveric procurement techniques; organ preservation solutions; management of the recipient abdominal wall; technical modifications, pitfalls and recommendations to be applied during the engraftment as well as intestinal living donation will be covered.

SUMMARY

Intestinal transplantation has evolved over time to become a clinically accepted therapy for patients with intestinal failure. Short- and long-term results have improved. The surgical procedures have been standardized and the applications broaden, but there have been recently published refinements that might affect the future results of clinical intestinal transplantation and guide research.

Evolution of the immunosuppressive strategies for the intestinal and multivisceral recipients with special reference to allograft immunity and achievement of partial tolerance

Introduction of new innovative immunosuppressive strategies has been the milestone of the recent evolution of intestinal and multivisceral transplantation. With new insights into the mechanisms of organ engraftment and acquired tolerance, the Pittsburgh tolerogenic protocol was recently introduced and consisted of two main therapeutic principles: recipient pretreatment with lymphoid ablating antibodies and minimal post-transplant immunosuppression with tacrolimus monotherapy. The reported herein improved survival and the striking ability to wean immunosuppression among the intestinal and multivisceral recipients pretreated with a single-dose of Thymoglobulin (rATG) or Campath-1H (alemtuzumab) supports our working hypothesis with successful induction of variable tolerance. It is important, however, that careful monitoring of subtle histologic changes in serial endoscopic-guided mucosal biopsies be carried out for early diagnosis of allograft immune activation with prompt restoration of the baseline immunosuppressive therapy. Future scientific discoveries with better understanding of the mechanisms of immune tolerance and clinical introduction of reliable assays will increase the chance and safety of achieving complete tolerance among the intestinal and other solid organ recipients. This review will focus on the historic evolution of the immunosuppressive and other management strategies utilized for the intestinal and multivisceral recipients at the University of Pittsburgh with special reference to allograft immunity and the successful achievement of partial tolerance.

Therapeutic efficacy of intestinal and multivisceral transplantation: survival and nutrition outcome

The clinical introduction of intestinal transplantation has added a new dimension and offered a valid therapeutic option for patients with irreversible intestinal failure. In the year 2000, the Center for Medicare & Medicaid Services (CMS) recognized intestinal, combined liver-intestinal, and multivisceral transplantation as the standard of care for patients with irreversible intestinal and parenteral nutrition (PN) failure. Accordingly, the indications for the procedure are currently limited to those who develop life-threatening PN complications. However, a recent improvement in survival similar to other solid organ transplant recipients should justify lifting the current restricted criteria, and the procedure should be considered before the development of PN failure. Equally important is the awareness of the recent evolution in nutrition management and outcome after transplantation. Early and progressive enteral feeding using a complex polymeric formula is safe and effective after successful transplantation. Full nutrition autonomy is universally achievable among most intestinal and multivisceral recipients, with enjoyment of unrestricted oral diet. Such a therapeutic benefit is commonly maintained among long-term survivors, with full rehabilitation and restoration of quality of life.

Treatment of intestinal failure: intestinal transplantation

Over the past 15 years, intestinal transplantation for the treatment of intestinal failure has changed from a desperate last-ditch effort into a standard therapy for which a good outcome is expected. Patient survival after intestinal transplantation has improved in the past 3-5 years and now approaches that of other solid organ allograft recipients, including liver and kidney, and is similar to survival on permanent therapy with parenteral nutrition. Complications are more common and often more severe during the initial hospitalization period after intestinal transplantation than they are after transplantation of other solid organs. After intestinal transplantation the initial hospitalization period is, therefore, usually 3-8 weeks long. Nearly all patients discharged after intestinal transplantation have good allograft function and have been weaned from total parenteral nutrition. The cost of the initial hospitalization period is one to two times the cost of permanent total parenteral nutrition for 1 year, which means that, in most cases, intestinal transplantation is cost-saving within 2 years of transplantation. In addition, quality of life after intestinal transplantation, as determined by standardized quality of life measures, is good or normal.

Small intestine transplantation today

INTRODUCTION

Intestinal transplantation has become a life-saving therapy in patients with irreversible loss of intestinal function and complications of total parenteral nutrition.

DISCUSSION

The patient and graft survival rates have improved over the last years, especially after the introduction of tacrolimus and rapamycin. However, intestinal transplantation is more challenging than other types of solid organ transplantation due to its large amount of immune competent cells and its colonization with microorganisms. Moreover, intestinal transplantation is still a low volume procedure with a small number of transplanted patients especially in Germany. A current matter of concern is the late referral of intestinal transplant candidates.

CONCLUSION

Thus, patients often present after onset of life-threatening complications or advanced cholestatic liver disease. Earlier timing of referral for candidacy might result in further improvement of this technique in the near future.

Modified multivisceral transplantation with splenopancreatic preservation

A common requirement of multivisceral transplantation has been removal of the native duodenum, pancreas and spleen in the process of abdominal exenteration. Oftentimes, though, the indication for their removal has not been underlying disease states in those organs. In order to avoid adverse sequelae of pancreas and splenic removal for purely anatomic reasons, we have designed a new approach and have performed a multivisceral transplantation with splenopancreatic preservation. In this modified multivisceral technique, the native spleen and pancreas are preserved with venous outflow through a native portocaval shunt, and native pancreatic exocrine drainage is established to the donor jejunum. Risk of transplant pancreatic insufficiency, posttransplant lymphoproliferative disorder, and postsplenectomy sepsis may be avoided utilizing this technique. This new modification of multivisceral transplantation allows pancreaticosplenic preservation while facilitating stomach replacement for those patients requiring intestinal replacement therapy. It represents another step towards minimizing morbidities associated with these lifesaving transplants.

Novel application of ProteinChip technology exploring acute rejection markers of rat small bowel transplantation

BACKGROUND

Because no biomarker that reflects small bowel allograft rejection is available, we applied surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) to develop noninvasive markers required for routine diagnosis.

METHODS

Heterotopic small bowel transplantation (SBT) was performed in rats, and they were divided into four experimental groups: sham-operated rats (sham), syngeneic transplants (syngeneic), allogeneic transplants (allogeneic), allogeneic transplants received FK506 (allo+FK). Plasma samples were analyzed with SELDI ProteinChip arrays to detect peaks that predominated in the allogeneic model. Possible biomarkers were identified in combination with SELDI retentate chromatography mass spectrometry (RCMS) and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The identified protein was further analyzed by immunohistochemistry.

RESULTS

An increase in the level of a 14.8-kDa protein, identified as lysozyme, was observed specifically in the plasma of the allogeneic group; the levels of this protein remained unchanged in the plasma of the other groups. On the other hand, the levels of a 10.1-kDa and a 13.0-kDa protein, identified as migration inhibitory factor-related proteins (MRP), MRP-8 and MRP-14, respectively, began to increase from an early stage of acute rejection. We also observed that lysozyme-positive macrophages had strongly infiltrated the lamina propria during acute rejection.

CONCLUSIONS

We identified three plasma proteins-MRP-8, MRP-14, and lysozyme-that increased during small bowel allograft rejection. The identified proteins appeared to be markers for inflammation associated with allograft rejection. This proteomic approach will be useful for the identification of candidate biomarkers.

Incidence, clinical significance, and outcome of vascular alterations in intestinal biopsies after isolated small bowel transplantation: a single-center experience

BACKGROUND

Mild and moderate vascular alterations in intestinal biopsies after isolated small bowel transplantation (SBT) have uncertain clinical significance.

METHODS

We retrospectively investigated the incidence, association with acute cellular rejection (ACR), treatment, and outcome of mild and moderate vascular changes in 15 adult SBTs performed between December 2000 and October 2003. The semiquantitative Ruiz score for vascular changes in intestinal mucosa was used.

RESULTS

A total of 332 biopsies were analyzed. All patients had at least one sample showing mild or moderate vascular injury, which was globally found in 117 biopsies (35% of the total; 29% mild and 6% moderate). No cases of severe vascular injury were observed. First appearance of vascular alterations occurred 2 to 36 days after SBT (median: 6). Patients with vascular injury had a higher incidence of associated ACR than patients without this feature (16% vs 5%, P = .001). Patients with moderate vascular injury were also more likely to have moderate-to-severe ACR than patients showing no or mild vascular changes (14% vs 2%; P = .015). Treatment of rejection was more frequently administered with simultaneous diagnosis of ACR than in cases of isolated vascular alterations (84% vs 26%; P < .0001). Only one graft (7%) was lost due to severe ACR.

DISCUSSION

Mild and moderate vascular changes are common findings in early post-SBT biopsies. They are frequently associated with ACR and parallel its severity. The clinical impact of mild or moderate vascular injury appears to be of little relevance.

An up-date review on individualized dosage adjustment of calcineurin inhibitors in organ transplant patients

Calcineurin inhibitors, tacrolimus (FK506) and cyclosporine (ciclosporin A), are the primary immunosuppressive agents used on recipients of organ transplantations. The hepatic metabolism of these drugs by cytochrome P450 IIIA (CYP3A) subfamilies is considered a major eliminating process. The intestinal efflux-pump P-glycoprotein (Pgp) (multidrug resistance 1 [MDR1], ATP-binding cassette B1 [ABCB1]) and CYP3A4 have been demonstrated as important for the bioavailability of drugs, so called "absorptive barriers". Recently, an important role for CYP3A5 in the intestine for the oral clearance of drugs has been identified. Both tacrolimus and cyclosporine are substrates of Pgp, CYP3A4 and CYP3A5, and therefore, these molecules are potential pharmacokinetic factors with which to establish personalized dosage regimens for these drugs. Although the effect of single nucleotide polymorphisms in the MDR1/ABCB1 and CYP3A5 genes on the pharmacokinetics of immunosuppressant has been widely examined, some contradictions have been emerged. In living-donor liver transplant (LDLT) patients, the intestinal mRNA expression level of MDR1 and CYP3A5 genotyping both in the native intestine and in the grafted liver are suggested to be potential pharmacokinetic factors for adjusting initial dosage and predicting post-operative variation in the pharmacokinetics of tacrolimus. We review the pharmacokinetic and pharmacodynamic characteristics of these drugs including the large pharmacokinetic variation and potential individualized dosage adjustments based on the genomic information of transporters and metabolic enzymes as well as classical pharmacokinetic analyses based on therapeutic drug monitoring (TDM).

Advances in the management of short bowel syndrome

Short bowel syndrome (SBS) is the predominant cause of intestinal failure and is thus associated with a high degree of morbidity and mortality. One of the reasons this occurs is the dramatic reduction in nutrient absorptive capacity. Of the many causes of SBS, the most common cause is extensive surgical resection. The impressive ability of the bowel to adapt functionally and morphologically is critical for decreasing morbidity and mortality in these patients. The degree of adaptation is vital in decreasing the dependence on parenteral nutrition (PN) and for improving patient quality of life and long-term outcome. Provision of appropriate and sufficient nutritional and fluid support is essential for the management of these patients. The primary goal is to prevent or eliminate the need for PN. Recent developments have promoted a greater understanding of the process of intestinal adaptation. Various intestinal trophic factors have been recognized. These efforts have led to the early development of hormonal therapy to stimulate intestinal adaptation and enhance intestinal absorption. Intestinal transplantation remains an option for those who have developed life-threatening complications from PN and cannot be managed using more conservative techniques.

Hand transplantation. A future clinical option?

Transplantation of a vascularized limb or its components is defined as composite tissue allotransplantation, and is one of the newest areas in surgery. To date, 24 hands have been transplanted onto 18 recipients. The initial results have been promising, and hand transplantation may become an important procedure for functional restoration of upper limbs. However, the ethical aspects of using chronic immunosuppression for a condition which is not life threatening have been the subject of debate. In this article, we review the field of composite tissue allotransplantation.

Anesthetic management for small bowel transplantation

Small bowel transplantation is quickly becoming the therapy of choice for short-gut syndrome. Improvements in surgical techniques, immunosuppressants, and anesthetic management of patients have allowed this procedure to become the standard of care for patients with irreversible intestinal failure who are unable to continue total parenteral nutrition therapy. This article discusses the evaluation process for candidate selection, including work-up for vascular access and hypercoagulability, intraoperative management of patients (including appropriate monitoring, hemodynamic changes, fluid management, surgical techniques, and effects of immunosuppressants), and patient survival and outcome.

Intestinal transplantation in children: a summary of clinical outcomes and prognostic factors in 108 patients from a single center

We performed 124 intestinal transplants on 108 children (median age, 1.5 years) since 1994. Initial graft types included isolated intestine (I) (n=26), liver and intestine (LI) (n=26), multivisceral (MV) (n=50), and multivisceral without liver (MMV) (n=6). Four groups were defined by type of induction therapy: none, OKT3, or cyclophosphamide (August 1994-December 1997, n=25), early experience with daclizumab (January 1998-December 2000, n=26), recent experience with daclizumab (January 2001-April 2004, n=40), and Campath-1H (January 2001-April 2004, n=17). Actuarial patient survival at 1 year for groups 1-4 was 44%+/-10%, 54%+/-10%, 83%+/-6%, and 41%+/-12%, respectively, with group 3 having the most favorable survival (P=0.0004). Using Cox stepwise regression, the hazard rate of developing severe rejection was significantly higher in patients with transplant type I or LI (P=0.0002), with no difference between these groups (P=0.24) but a significantly higher rate for LI versus MV (P=0.005). Three factors associated with improved patient survival were recipient of MV or MMV (P=0.008), age at transplantation greater than 1 year (P=0.01), and use of daclizumab (P=0.0006). Cause-specific hazard analysis revealed a decreased rate of rejection-related mortality for recipients of MV or MMV (P=0.0007), whereas age greater than 1 year indicated a lower rate of infection-related mortality (P=0.0009). Pediatric intestinal transplantation provides an increasingly realistic chance of survival, particularly with the more recent use of daclizumab and multivisceral transplantation. A protective effect of multivisceral transplantation appears to exist with respect to the development of severe rejection.

Evolutionary experience with immunosuppression in pediatric intestinal transplantation

BACKGROUND/PURPOSE

Intestinal transplantation has developed to become the standard of care for patients with irreversible intestinal failure who are not responding to total parenteral nutrition. Once considered experimental, it has taken time and much effort for the procedure to become a clinical reality, with final acceptance primarily because of the vastly improved outcomes. Advances and novel modifications in immunosuppression have been at the forefront of these improvements. The authors review their evolutionary experience with intestinal transplantation, particularly relating changes in immunosuppression protocols to improved outcomes.

METHODS

From July 1990 to December 2003, 122 children received 129 intestinal containing allografts (70 liver/intestine, 42 isolated intestine, 17 multivisceral). Mean age was 5.3 +/- 5.2 years, and 55% were boys. Indications for transplantation were mostly short gut syndrome. The allografts were cadaveric, ABO identical (except one), with no immunomodulation. Bone marrow augmentation was used in 29% of the recipients since 1995. T-cell lymphoctytotoxic crossmatch was positive in 24% cases. Immunosuppression protocols can be divided into 3 categories: (i) maintenance tacrolimus and steroids (n = 52, 1990-1995, 1997-1998); (ii) addition of induction therapy with cyclophosphamide (n = 16, 1995-1997) then daclizumab (n = 24, 1998-2001). A third immunosuppressive agent was added in either group where increased immunosuppression was indicated; (iii) pretreatment/induction with antilymphocyte conditioning and steroid-free posttransplantation tacrolimus monotherapy (n = 37, 2002-2003). In this later group, if clinically stable at 60 to 90 days posttransplantation, and no recent rejection, the tacrolimus was weaned by decreasing frequency of dosing.

RESULTS

The overall Kaplan-Meier patient/graft survival was 81%/76% at 1 year, 62%/60% at 3 years, and 61%/51% at 5 years. Survival continues to improve, with 1-year patient/graft survival being 71%/62%, 77%/75%, and 100%/100% for groups (i), (ii), and (iii), respectively. Acute intestinal allograft rejection has decreased markedly in group (iii). The rate of infectious diseases, such as cytomegalovirus and Epstein-Barr virus, is lowest in group (iii). Graft-versus-host disease has not significantly increased with the latest protocol. Most importantly, the overall level of immunosuppression requirements has decreased markedly, with most patients in group (iii) being on monotherapy. Of these, most had their monotherapy weaned down to spaced doses, something never systematically attempted or achieved in pediatric intestinal transplantation.

CONCLUSIONS

Intestinal transplantation has progressed markedly over the last 13 years. Although there have been modifications in all aspects of the procedure, the story of intestinal transplantation has been the evolution of successful immunosuppression regimens. Our latest pretreatment/induction conditioning and posttransplantation monotherapy strategy improves graft acceptance and lowers subsequent immunosuppression dosing requirements. It is expected this will overcome many of the complications related to the previously high immunosuppression requirements. Minimization of immunosuppression with avoidance of steroid therapy offers profound long-term benefits, especially in the pediatric population. The patients still remain challenging and complex in every aspect; however, these advances offer significant hope to both patients and caregivers alike.

Time-dependent morphological alterations of cold-stored small bowel in Euro-Collins and Ringer's lactate solutions

Small bowel is one of the organs that can in principle be transplanted. Optimum preservation of the organ is essential for the success of transplantation. The aim of the present study is the investigation of time-related morphological changes of rat small bowel during preservation in hypothermic Euro-Collins (EC) and Ringer's lactate (RL) solution using light microscopy and transmission electron microscopy to evaluate the integrity of intercellular complexes of mucosal epithelium, one of the tissues of the intestine that is most susceptible to ischemia. Small bowels were perfused with either EC, RL solution or physiological saline solution and were placed in the different preservation solutions at 4 degrees C for 0, 3, 6 and 12 h. The results of our study suggest that both preservation solutions are suitable for short-term preservation of the small bowel although RL solution is more effective than EC solution. However, we conclude that further improvement of preservation solutions and/or techniques are needed to perform long-term preservation.

Intestinal transplantation for chronic intestinal pseudo-obstruction in adult patients

Intestinal transplantation (ITx) has become a life-saving procedure for patients with irreversible intestinal failure who can no longer be maintained on parenteral nutrition (PN). This report presents the results of our experience on ITx in patients suffering from chronic intestinal pseudo-obstruction (CIPO). Between December 30, 2000 and May 30, 2003 six adult patients affected by CIPO underwent primary ITx at our Center. Pre-transplant evaluation, indication for ITx and surgical technique are reported. On December 30 2003, the mean follow-up was 25.0 months. No peri-operative deaths occurred in the study population and five out of six patients are alive, with 1-year patient and graft survival of 83.3% and 66.6%. Although our series is limited by the number of patients, our experience suggests that ITx transplantation should be considered in adult patients suffering from CIPO and PN life-threatening complication.

Gut failure and abdominal visceral transplantation

Despite the reported high survival with total parenteral nutrition (TPN) therapy for patients with intestinal failure, a considerable number of patients do not escape the potential risks of TPN-associated complications, including hepatic failure, vanishing of central venous access and line sepsis. Thus, intestinal, liver-intestinal and multivisceral transplantation have recently emerged to rescue those who can no longer be maintained on TPN. Before this development, and for nearly three decades, small-bowel transplantation was plagued with uncontrolled rejection, graft v. host disease and fatal infection. These barriers stemmed from the large gut lymphoid mass and heavy microbial load contained in the intestinal lumen. The recent improvement in survival after the clinical introduction of tacrolimus with achievement of full enteric nutritional autonomy qualified the procedure by the US Health Care Financing Administration as the standard of care for patients with intestinal and TPN failure. The decision was supported by a decade of clinical experience with cumulative improvement in patient and graft survival. In addition, the introduction of new effective immunoprophylactic agents and novel therapeutic approaches has contributed to a further increase in the therapeutic advantages of the procedure. The present review article outlines the current clinical practice of intestinal transplantation and defines new management strategies with the aim of raising the level of the procedure to be a better alternative therapy for TPN-dependent patients.

Three-year experience in clinical intestinal transplantation

BACKGROUND

The purpose of this study was to evaluate the outcome of 19 patients who underwent intestinal transplantation (ITx) for intestinal failure.

METHODS

The 19 patients who underwent primary ITx between December 2000 and May 2003 were prescribed three different immunosuppressive protocols that included daclizumab, alemtuzumab, and antithymocyte globulin induction, respectively. A mucosal surveillance protocol for early detection of rejection consisted of zoom video endoscopy and serial biopsies associated with orthogonal polarization spectral imaging. Retrospective review of the clinical records was performed to assess the impact of new modalities of immunosuppression and intestinal mucosal monitoring on patient outcomes.

RESULTS

All patients were adults (mean age 35.8 years). Etiology of intestinal failure included chronic intestinal pseudo-obstruction (n = 6), intestinal angiomatosis (n = 1), Gardner syndrome (n = 2), intestinal infarction (n = 8), radiation enteritis (n = 1), and intestinal atresia (n = 1). All patients experienced complications from total parenteral nutrition (TPN). Thirteen patients (68.4%) received isolated small bowel, whereas six (31.6%) received multivisceral grafts with or without the liver. Thirteen of 19 patients experienced at least one episode of rejection (68.4%). Most ACR episodes were treated with steroid boluses and resolved completely within 5 days. The overall 1-year patient survival was 82%. All living patients are in good health with functioning grafts having been weaned off TPN after a mean of 23.7 days post-ITx.

DISCUSSION

Advances in immunosuppressive therapy with early detection and prompt treatment of rejection episodes make ITx a valuable treatment option for patients with intestinal failure and TPN-related life-threatening complications.

Modifications in combined liver-small bowel transplantation in pigs

AIM: To introduce combined liver-small bowel transplantation in pigs.

METHODS: Eighteen transplantations in 36 large white pigs were performed. Three modifications in combined liver-small bowel transplantation model were applied: Veno-venous bypass was not used. Preservation of the donor duodenum and head of pancreas in continuity with the combined graft to avoid biliary reconstruction. The splenic vein of donor was anastomosed end-to-end with the portal vein of recipients by the formation of a “cuff”.

RESULTS: Without immunosuppressive therapy, 72-hour survival rate of the transplanted animals was 72% (13/18). Five of 18 pigs operated died of respiratory failure (3 cases) and bleeding during hepatectomy (2 cases). The longest survival time of animals was 6 days.

CONCLUSION: Our surgical modifications are feasible and reliable, which have made the transplantation in pigs simpler and less aggressive, and thus these can be used for preclinical study.

Isolated intestinal transplantation: proof of clinical efficacy

BACKGROUND AND AIMS

Isolated intestinal transplantation has been limited by poor patient and graft survival. If high survival could be achieved and if parenteral nutrition-associated liver disease were reversible, this procedure could be more widely applied, with early liver dysfunction indicating the need for transplant evaluation.

METHODS

Twenty-six patients who had failed parenteral nutrition received 28 isolated intestinal transplants. We analyzed patient and graft survival, the effect of sirolimus on the severity and frequency of rejection, and the reversibility of liver dysfunction after transplant.

RESULTS

Three-year actuarial patient and primary graft survival were 88% and 71%, respectively. Two patients underwent successful retransplants. Twenty-two patients are alive at a mean of 21+/-15 (median 18; range 3-51) months. Actuarial survival with freedom from parenteral support is 81% at 3 years (21 of 26 patients). Actuarial freedom from parenteral support among survivors is 95.5% at 3 years (21 of 22 patients). Early rejection was less frequent with sirolimus (34% vs. 70% without sirolimus) (P=0.007). Moderate and severe rejection was less frequent with sirolimus (1/11 episodes vs. 9/17 episodes without sirolimus) (P=0.05). No grafts were lost after introduction of sirolimus. In all four patients with advanced liver dysfunction, fibrosis and cholestasis regressed within 1 year.

CONCLUSIONS

High patient survival and parenteral nutrition-free survival can be achieved after isolated intestinal transplantation. Sirolimus treatment has eliminated graft loss. Parenteral nutrition-associated liver disease is reversible with intestinal transplantation. Refractory liver dysfunction in patients receiving parenteral nutrition should prompt consideration for isolated intestinal transplantation.

Morphology and function of canine small intestinal autografts: with particular interest in the influence of ex vivo graft irradiation

The intestinal transplantation procedure obligates an early functional deficit in intestinal grafts. Graft irradiation has been used to modulate post-transplant immune reactions; however, irradiation may cause further deterioration of the function of the transplanted intestine. Using the canine model, we investigated the influence of the transplant procedures, with and without ex vivo graft irradiation, on early intestinal graft function and histopathology. Outbred hound dogs underwent autointestinal transplantation with (n=8) or without (n=5) 7.5 Gy ex vivo graft irradiation. Mucosal cytochrome P450 and P-glycoprotein, routine immunohistopathology, and intestinal absorptive function were studied. Weight gain was slow after surgery, but was comparable in the irradiated and nonirradiated groups. During the early post-transplant period, both groups showed defects in intestinal absorption, associated with decreased cytochrome P450 3A4 activity and reduced P-glycoprotein expression, regardless of graft irradiation. These changes returned to normal in both groups by day 28. Histopathologically, epithelial apoptosis showed a slight increase 1 hour after transplantation; however, there was no evidence of histopathologic abnormalities including arterial changes associated with irradiation. In addition, the frequency of T and B lymphocytes in the lamina propria were not significantly influenced by the transplant surgery or ex vivo irradiation. Thus, early after transplantation, intestinal function was impaired and effectiveness of orally administered immunosuppressive drugs was significantly altered. Graft irradiation did not induce further defects in intestinal function or cause histopathologic abnormalities.

Scanning electron microscopic study of cold-stored small bowel: comparison of Euro-Collins and Lactated Ringer's solutions

The increasing use of the small bowel for transplantation necessitates the development of optimum preservation techniques. The aim of our study was to investigate time-related morphological changes of the rat small bowel during preservation of the organ in hypothermic Euro-Collins and Lactated Ringer's solutions. It is the only study comparing these widely used preservation solutions with scanning electron microscopy, which is especially suitable to show the intestinal mucosa, one of the tissues of the intestine most susceptible to ischemia. Small bowels were perfused with either Euro-Collins, Lactated Ringer's or physiological saline solution and placed in respective preservation solutions at 4 degrees C for 0, 3, 6 and 12 hours. Biopsy samples were prepared for examination at the light and scanning electron microscopic levels. According to the results of this study we conclude that, even Lactated Ringer's solution showed better tissue preservation than Euro-Collins solution, both preservation solutions are suitable for short term preservation of the small bowel and that further ameliorations of the preservation solutions and/or techniques are required for long term preservation.

Mucosal vascular alterations in isolated small-bowel allografts: relationship to humoral sensitization

Acute vascular rejection (AVR) in human small-bowel transplantation is an inadequately characterized entity whose frequency and severity is not well understood. As compared to severe AVR, changes identifying early, mild or evolving AVR are not known. We created a scoring system to evaluate subtle mucosal vascular changes and examined 188 biopsies from 21 patients obtained in the first 3 months post transplant. A majority of patients had a transient rise in vascular injury, often within 30 days of transplant. Small-vessel congestion and erythrocyte extravasation were the most common alterations. The vascular injury score was not related to acute cellular rejection, HLA type or HLA antigen disparities. However, the patients with the vascular changes had significantly higher peak panel reactive antibodies (PRA) and a higher incidence of positive T-cell and B-cell crossmatch. Finally, graft survival was significantly lower in the patients demonstrating the early vascular lesions. These data suggest that the vascular injury is partially associated with humoral presensitization of the recipient and may be a form of acute vascular rejection. Since these vascular changes are frequent, we advocate early post-transplant monitoring to identify and manage potentially high-risk patients.

Combined small bowel and reduced auxiliary liver transplantation: Case report

AIM: To present a case of combined small bowel and reduced auxiliary liver transplantation.

METHODS: A 55-year-old patient with short bowel syndrome and TPN-related liver dysfunction received small bowel transplantation combined with a reduced auxiliary liver graft. A liver was added to restore the patient's liver function and to protect the intestinal allograft from rejection. His own liver was not removed.

RESULTS: Without donor pretreatment and by conventional immunosuppresive therapy following transplantation, the patient experienced had only one episode of mild intestinal rejection, which was easily reversed by treatment with Methylprednisolone. No liver rejection occurred. Unfortunately, the patient died of heart and lung failure 30 d after transplantation, despite successful graft replacement. Histopathologic examination of specimens after death demonstrated normal structure in both intestinal and liver grafts.

CONCLUSION: The auxiliary liver graft might play a role in preventing intestinal allograft rejection. However, the observation period in this case is short. Further study is needed to determine the risks, effect on the protecting the small-bowel from rejection, and feasibility of general application of this procedure.