Clinical intestinal transplantation: new perspectives and immunologic considerations

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.

Indications for and outcomes after combined lung and liver transplantation: a single-center experience on 13 consecutive cases

BACKGROUND

Combined lung and liver transplantation (Lu-LTx) is a therapeutic option for selected patients with coexisting lung and liver disease. For several reasons, Lu-LTx is performed in few centers and information about the technical issues, posttransplant management and long-term outcomes associated with this procedure is limited.

METHODS

We analyzed data from 13 consecutive patients who underwent combined Lu-LTx at Hannover Medical School (Hannover, Germany) between April 1999 and December 2003. The main indications were cystic fibrosis, alpha1-proteinase inhibitor deficiency and portopulmonary hypertension. All patients had advanced cirrhosis and severe pulmonary disease manifestation.

RESULTS

Ten patients received a sequential double Lu-LTx, one patient received a single Lu-LTx, one received a double lung and split liver transplantation, and one received an en-bloc heart-lung and liver transplantation. Immunosuppression was based on cyclosporine in a triple/quadruple regimen. Postoperative surgical complications occurred in eight patients. There were two perioperative deaths; two patients died during the first year on day 67 and 354, respectively, and one patient died at month 53. The overall patient survival rates at 1, 3, and 5 years were 69%, 62%, and 49%, respectively.

CONCLUSION

Combined Lu-LTx is a therapeutic option for highly selected patients with end-stage lung and liver disease with acceptable long-term outcome.

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.

Urogenital Disorders Associated With Gut Failure and Intestinal Transplantation

PURPOSE

Intestinal transplantation has been increasingly performed in patients with short bowel syndrome and irreversible gut failure with successful outcomes. In parallel a common association was observed between gut failure and different urological disorders. To our knowledge this study is the first to address such an important clinical observation with special reference to the underlying disease.

MATERIALS AND METHODS

The medical records of 175 consecutive adult intestinal recipients were reviewed. Data were compiled and described according to the documented urogenital disorder, cause of intestinal failure and treatment modality, including transplantation.

RESULTS

Of the patients 43 experienced a total of 53 urogenital disorders for an overall incidence of 25%, including 24 (56%) who had the disorder before referral and 19 (44%) in whom the morbidity developed as a result of transplantation. Interestingly hypercoagulability, pseudo-obstruction, Crohn's disease and Gardner's syndrome were the underlying urogenital and intestinal disorder pathologies in 6.3% of the study patients. Treatment for prior urogenital disorders, including malignancy, precipitated intestinal failure in 3.4% of the referred patients. Reciprocally surgical treatment for the primary intestinal disease and management of gut failure by total parenteral nutrition, followed by transplantation, resulted in different urogenital complications in 17.7% of the total population with an 8.6% incidence of chronic renal failure.

CONCLUSIONS

Gut failure and intestinal transplantation are commonly associated with different urogenital disorders. Accordingly a designated urological service should be considered part of the multidisciplinary team required for treating this unique population.

The ?Blind Innsbruck Ostomy?, a cutaneous enterostomy for long-term histologic surveillance after small bowel transplantation

Intestinal transplantation has evolved into an established treatment for patients with intestinal failure. Although acute rejection episodes are reversible, late onset and chronic rejections remain major prognostic factors. We describe here our experience with endoscopic and histologic long-term monitoring through a cutaneous enterostomy. Between 1989 and 2003, 24 intestinal transplants were performed. After revascularization and reconstruction of proximal intestinal continuity, a side-to-end ileo-enterostomy was performed 20 cm from the stoma and the terminal allograft ileostomy left in the abdominal wall. Approximately after 2 months, in eight patients (nine transplants), the stoma was excluded from the gastrointestinal continuity, allowing ongoing endoscopy and histologic examination. Of 280 forceps biopsies, 64 (23%) were performed through the 'blind ostomy'. Eleven acute allograft rejections were diagnosed between days 3 and 51, with two episodes in three cases. Through the 'blind ostomy', a late mild acute rejection was diagnosed in five instances, three to 37 months after transplantation. In all these patients, basal immunosuppression was intensified. Chronic rejection was seen in three cases 4-26 months after transplantation. In one of the three patients, chronic rejection was diagnosed from the excluded blind enterostomy. A long-term cutaneous enterostomy, even if disconnected from the intestinal continuity, enables simple long-term monitoring of small bowel allografts.

The pig-to-primate immune response: relevance for xenotransplantation

BACKGROUND

The allotransplantation of some solid organs can be associated with a graft-vs.-host (GVH) response from the activity of donor B or T cells. We have investigated whether there is a risk of a GVH response following pig-to-primate organ xenotransplantation.

METHODS

The responses of 16 pigs (six farm-housed wild-type and five wild-type housed under high herd health conditions [all designated WT], and 5 alpha1,3-galactosyltransferase gene-knockout [GT-KO] housed under high herd health conditions) to human (n = 6) and baboon (n = 6) peripheral blood mononuclear cells (PBMC) were determined. Assays included flow cytometry, complement-dependent cytotoxicity, and mixed lymphocyte reaction.

RESULTS

Anti-primate cytotoxic IgM antibodies were detected in the sera of all pigs, but anti-primate IgG antibodies were minimal. All pigs demonstrated a cellular proliferative response to primate PBMC that was equivalent to, or greater than, the allo response. The strength of the pig-to-primate GVH responses was proportional to the health status of the pigs, those from a high health status herd, particularly from a specific pathogen-free herd maintained under clean husbandry conditions, where colonization of the gastrointestinal tract may be reduced, having lower responses.

CONCLUSIONS

After pig organ transplantation in a primate, if the organ is from an early-weaned, early-segregated GT-KO pig, the strength of a GVH response is likely to be relatively weak. Although not investigated here, any GVH response is likely to be suppressed by the immunosuppressive therapy administered to the recipient to suppress the anti-donor immune response.

Short bowel syndrome: parenteral nutrition versus intestinal transplantation. Where are we today?

Current management of short bowel syndrome (SBS) revolves around the use of home TPN (HPN). Complications include liver disease, catheter-related infections or occlusions, venous thrombosis, and bone disease. Patient survival with SBS on TPN is 86% and 75% at 2 and 5 years, respectively. Surgical management of SBS includes nontransplant surgeries such as serial transverse enteroplasty and reanastomosis. Small bowel transplant has become increasingly popular for management of SBS and is usually indicated when TPN cannot be continued. Posttransplant complications include graft-versus-host reaction, infections in an immunocompromised patient, vascular and biliary diseases, and recurrence of the original disease. Following intestinal-only transplants, patient and graft survival rate is 77% and 66% after 1 year. After 5 years the survival figures are 49% and 34%, respectively. Future improvements in survival and quality of life will enhance small bowel transplant as a viable treatment option for patients with SBS.

Two-step procedure of whole orthotopic intestinal transplantation in rats: considerations of techniques and graft functional adaptation

Intestinal transplantation may eventually become the definitive therapeutic modality for irreversible intestinal failure. To date, immunological, functional, and technical problems still hamper clinical success. In this paper, the technical aspects of a two-stage procedure for a whole orthotopic intestinal transplantation model of rats with systemic drainage are illustrated. Graft mucosal Na(+)/K(+)-ATPase and disaccharidase revealed recovery of graft function. From this study, we conclude that the present model may provide an excellent tool to further investigate the physiology and immunology of intestinal transplantation.

Absorption of orthotopically transplanted intestine in rats: evaluation of amino acid absorption

During the early phase of our intestinal transplant program, a low-lipid, amino acid-based feeding was employed for most recipients. However, relatively little is known regarding the amino acid absorption by a graft following intestinal transplantation. Sixty Wistar rats were randomly divided into two groups (n = 30). The animals received two-step orthotopic intestine transplantation (OIT), or the control; enterectomy with anastomoses. We measured mucosal Na(+)/K(+)-ATPase and intestinal absorption using stable isotope techniques in vivo. Compared with controls, mucosal Na(+)/K(+)-ATPase activity in OIT decreased by 38.3% and 38.4% at 2 and 4 weeks, and returned to baseline and control group values at 8 weeks. Glycine absorption decreased at 2 weeks and returned to baseline at 4 weeks in OIT compared with that in controls. These results suggested that absorption as assessed by mucosal Na(+)/K(+)-ATPase and glycine, returned to baseline at least 4 weeks after transplantation.

Histopathologic characteristics of human intestine allograft acute rejection in patients pretreated with thymoglobulin or alemtuzumab

BACKGROUND

We report herein the histopathologic characteristics of human intestine allograft acute rejection in a consecutive series of 48 patients receiving small bowel transplantations and treated with a preconditioning protocol between July 4, 2001 and January 31, 2004.

METHODS

Recipient pretreatment was with an i.v. infusion of 5-10 mg/kg thymoglobulin or 30-60 mg of alemtuzumab (Campath 1H) over several hours prior to revascularization. Postoperative treatment was limited to tacrolimus (target 12-h trough level 10-15 ng/mL) unless additional drugs were needed to treat breakthrough rejection.

RESULTS

A total of 3,497 biopsies of the allograft jejunum and/or ileum were obtained. A recently validated histological grading schema was prospectively utilized to grade acute rejection. A total of 116 acute rejection episodes were diagnosed (48 indeterminate, 36 mild, 11 moderate, and 21 severe). Several unique histopathologic features of allograft acute rejection were observed in the pretreated patients. First, scattered lamina propria neutrophilic inflammation often precedes the onset of acute rejection. Second, acute rejection is often associated with more prominent eosinophils in lamina propria or eosinophilic cryptitis. Third, certain acute rejection episodes are characterized by absence of crypts with intact surface villous epithelium. Finally, the mucosal damage associated with moderate or severe acute rejection can completely recover after additional immunosuppressive treatment.

CONCLUSION

This study describes several characteristic histopathologic features of allograft small bowel acute rejection associated with thymoglobulin or alemtuzumab preconditioning. Recognition of these unique histopathologic features will enable accurate diagnosis and ensure successful weaning of immunosuppressive drugs.

Intestinal replacement therapy: timing and indications for referral of patients to an intestinal rehabilitation and transplant program

Current treatment options for patients suffering from intestinal insufficiency include all forms of intestinal replacement therapy (IRT). Parenteral nutrition has achieved extended success for the majority of patients requiring interval treatment, however, complications leading to failure of this treatment increases with the duration of therapy. There is currently no consensus as to the appropriate timing for transplantation of the intestine or the timing of referral for evaluation at a center experienced with this therapy. Certain patient characteristics warrant evaluation. Those patients with no jejunoileum who have guaranteed lifelong parenteral dependence, both adult and pediatric, should be immediately referred to a transplant center due to the high likelihood of the development of liver disease. Patients with metastatic infectious complications from catheter sepsis, patients with cholestasis seen intermittently with sepsis episodes, patients who are not successfully weaning and who demonstrate progressive thrombocytopenia, and patients with motility disorder experiencing deterioration should also warrant early referral to an intestinal rehabilitation and transplant program. The objective of evaluation is to maximize the opportunities for rehabilitation while not missing the critical window of opportunity for successful transplantation when needed. We favor an aggressive directed approach to rehabilitation, coupled with psychological preparation for both transplantations and other options. Early referral requires trust between the patient, referring physician, and the transplant team to assure that a rush to judgment will not lead to a premature transplant. The current wait list mortality is high, mandating early referral and listing with an approach aimed at maximizing both the success of gastrointestinal support, as well as of transplantation when necessary.

Monitoring immune function during tacrolimus tapering in small bowel transplant recipients

Long term use of immunosuppressants impacts the cardiovascular system and increases the risk of infection and malignancy. To effectively reduce immunosuppression in a transplant recipient a tool is needed to directly monitor the level of immune function. The Cylex(R) Immune Cell Function Assay, approved by the FDA for the assessment of cell-mediated immunity, shows promise as an objective measure of a transplant recipient's immune function. In a blinded retrospective study, the immune function was compared to clinical courses and histological examinations of biopsies of 20 small bowel transplant recipients during periods of immunosuppressant tapering. Eight patients with no major adverse events or changes of immunosuppressive therapy had moderate to low immune function and were categorized as immunologically and clinically stable. Twelve patients displaying strong immune responses were immunologically and clinically volatile requiring addition of steroids and or OKT3. Results validate the clinical utility of the Cylex Immune Cell Function Assay as an objective tool for assessing immune function. By evaluating immune function, physicians now can identify those patients who are candidates for minimization of immunosuppressant therapy, manage the timing and rate of immunosuppressant weaning and be forewarned of increased patient risk.

Intestinal transplantation under tacrolimus monotherapy after perioperative lymphoid depletion with rabbit anti-thymocyte globulin (thymoglobulin)

Modifications in the timing and dosage of immunosuppression can ameliorate the morbidity and mortality that has prevented widespread use of intestinal transplantation (ITx) in children. Thirty-six patients receiving ITx, aged 5 months to 20 years were given 2-3 mg(kg of rabbit anti-thymocyte globulin (rATG, thymoglobulin) just before ITx, and 2-3 mg(kg postoperatively (total 5 mg(kg). Twice daily doses of tacrolimus (TAC) were begun enterally within 24 h after graft reperfusion with reduction of dose quantity or frequency after 3 months. Prednisone or other agents were given to treat breakthrough rejection. After 8-28 months follow-up (mean 15.8 +/- 5.3), 1- and 2-year patient and graft survival is 100% and 94%, respectively. Despite a 44% incidence of acute rejection in the first month, 16 of the 34 (47%) survivors are on TAC (n = 14) or sirolimus (n = 2) monotherapy; 15 receive TAC plus low dose prednisone; one each receive TAC plus sirolimus, TAC plus azathioprine and TAC plus sirolimus and prednisone. There was a low incidence of immunosuppression-related complications. This strategy of immunosuppression minimized maintenance TAC exposure, facilitated the long-term control of rejection, decreased the incidence of opportunistic infections, and resulted in a high rate of patient and graft survival.

Liver transplantation for severe hepatic graft-versus-host disease: an analysis of aggregate survival data

Graft-versus-host disease (GVHD) often occurs after bone marrow transplantation (BMT). GVHD may lead to cirrhosis or complete destruction of the bile ducts, and few effective treatment options exist for such cases. Orthotopic liver transplantation (OLT) has been described as an option, but to date the patient survival, graft survival, and GVHD recurrence rates after OLT have been unknown. Cases of OLT for GVHD were accumulated from several sources: (1) cases of OLT performed at a single institution, (2) the English-language medical literature, and (3) the United Network for Organ Sharing (UNOS) liver transplant registry. Descriptive data were derived from pre- and post-OLT information; survival analysis was performed using the Kaplan-Meier method. One case of OLT for GVHD after BMT was found at our institution, and another 6 cases were previously reported in the literature. Extrahepatic GVHD recurred in 2 cases, but no recurrence of hepatic GVHD was reported. The UNOS registry contained an additional 73 patients who underwent OLT for hepatic GVHD. The 1- and 5-year actuarial patient survival rates were 72.4% and 62.9%, respectively. Although 4 patients required retransplantation, no deaths or retransplants were attributed to the recurrence of hepatic GVHD. OLT is an effective treatment for hepatic GVHD after BMT or non-liver organ transplant. Long-term disease-free survival is obtainable in these cases, and recurrence of hepatic GVHD has not been reported. These findings suggest that OLT should be considered as an effective treatment option for cases of hepatic GVHD recalcitrant to medical treatment.

Intestinal transplantation: an update

PURPOSE OF REVIEW

As outcomes with intestinal transplantation continue to improve, its role in the management of intestinal failure patients becomes clearer. Some intestinal failure patients do well with long-term total parenteral nutrition (TPN), while others develop life-threatening complications and need to be evaluated for intestinal transplants (ITs). The purpose of this review is to update the current status of intestinal transplantation and its role in the management of intestinal failure patients.

RECENT FINDINGS

Current outcomes indicate that intestinal transplants should be considered earlier in intestinal failure patients that develop liver injury, to prevent irreversible liver disease that would mandate a simultaneous liver transplant. Due to the small bowel (SB) graft's unique immunobiologic features, it is especially challenging to transplant successfully. Although new immunosuppressive strategies have been developed that appear to improve short-term results, their impact on long-term outcomes has yet to be shown. A better understanding of the interactions that occur between the SB's inherent immune system and its luminal flora may be required to devise strategies that will significantly curtail the SB graft's immunogenicity.

SUMMARY

Intestinal transplantation remains a significant challenge. Ongoing efforts to better define the parameters that best predict total parenteral nutrition failure and the unique mechanisms that influence small bowel allograft outcomes are necessary before a broader application of small bowel transplantation can be indicated.

A clinicopathologic study of isolated intestinal allografts with preformed IgG lymphocytotoxic antibodies

Humoral rejection of human small bowel allografts has not been well documented. The aim of this study was to determine the significance of preformed IgG lymphocytotoxic antibodies, as determined by the modified Amos crossmatch technique, in 6 of 28 (21.4%) adult isolated intestinal allograft recipients treated with tacrolimus basal immunosuppression. The crossmatch with dithiothreitol (DTT) was strongly positive in 5 grafts and weakly positive in the remaining one. The strongly positive crossmatch grafts (n=5) developed severe mucosal injuries immediately after reperfusion. Within the first 10 days after transplantation, 3 of the 5 strongly positive crossmatch grafts developed clinically and endoscopically documented severe mucosal congestion, cyanotic discoloration, and focal hemorrhage within the allograft. Simultaneous mucosal biopsy specimens demonstrated severe congestion, neutrophilic margination, and fibrin-platelet thrombi within the lamina propria microvasculature, along with focal hemorrhage, but with no histological neutrophilic or necrotizing arteritis, and the immunofluorescent findings were unremarkable. The other 2 strongly positive crossmatch allograft recipients developed macroscopic congestion of mucosa with microscopic foci of congestion and hemorrhage. In contrast, the recipient with a weakly positive crossmatch, as well as the 22 crossmatch negative recipients, exhibited none of these characteristic clinical, endoscopic, or microscopic findings (P <.05). With prompt augmentation of the immunosuppression therapy, the 3 grafts with the characteristic clinicopathologic syndrome were successfully reversed with the monoclonal antilymphocyte preparation OKT3. Thus there was no statistical difference (P >.05) in early graft survival and the frequency of acute rejection episodes between the crossmatch-positive and the crossmatch-negative groups within the first 6 months after transplantation. We conclude that preformed IgG lymphocytotoxic antibodies in isolated intestinal recipients can be associated with a characteristic clinicopathologic syndrome during the early postoperative course, similar to that observed in experimental animal models and in other solid organ transplantation. If recognized and treated aggressively, early graft failure can be avoided. The long-term significance of these preformed antibodies has yet to be determined.

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.

Intestinal transplantation for total/near-total aganglionosis and intestinal pseudo-obstruction

Whether from anatomical short gut (such as after resection of extensive intestinal aganglionosis) or from a functional cause (such as intestinal pseudoobstruction), intestinal failure is a devastating disease process with profound morbidity and mortality. These patients require total parenteral nutrition (TPN) and are at risk of developing complications such as liver failure, catheter-related sepsis and loss of venous access. Intestinal transplantation, which has advanced markedly over the last 14 years, is now the accepted standard of care for patients failing TPN. Survival outcomes have improved significantly, infectious complications are better controlled, and new immunosuppressive therapies offer great hope for the future. In particular, the results of intestinal transplantation achieved with the motility disorders are equivalent to those experienced with other causes of intestinal failure. In themselves, the motility disorders present their own set of complicating factors, including determining the extent of the disease process (which may involve any part of the gastrointestinal tract), associated urological anomalies, and the type of organ transplantation required. Extensive workup and careful consideration is required before transplantation is undertaken. However, early referral is desirable once complications arise if these patients are to be offered optimal medical care before the chance of transplantation is lost.

Combined 'en bloc' liver and pancreas transplantation in patients with liver disease and type 1 diabetes mellitus

Liver disease alters the glucose metabolism and may cause diabetes, but this condition is potentially reversible with liver transplantation (LTx). Type 1 diabetes mellitus may be coincidentally present in a LTx candidate and immunosuppressive drugs will aggravate diabetes and make its management more difficult for posttransplant. In addition, diabetes negatively influences outcome after LTx. Therefore, the question arises as to why not transplanting the pancreas in addition to the liver in selected patients suffering from both liver disease and Type 1 diabetes. We report two cases of en bloc combined liver and pancreatic transplantation, a technique originally described a decade ago in the treatment of upper abdominal malignancies but rarely used for the treatment of combined liver disease and Type 1 diabetes. Both recipients are currently liver disease-free and insulin-free more than 2 and 4 years posttransplant, respectively. Surgical, medical and immunological aspects of combined liver-pancreas transplantation are discussed in the light of the existing relevant literature.

The impact of portal infusion with donor-derived bone marrow cells and intracellular cytokine expression of graft-infiltrating lymphocytes on the graft survival in rat small bowel transplant model

BACKGROUND

Intraportal administration of alloantigen is reported to reduce antigen-specific immune responses, although the underlying mechanisms for the reduced immunological reactions, especially those of the graft, are poorly understood. We examined intracellular cytokine production by graft-infiltrating lymphocytes (GILs) and peripheral blood lymphocytes (PBLs) to elucidate the underlying mechanisms of beneficial effects on intraportal infusion of donor cells in rat small bowel transplantation (SBT).

METHODS

Recipient rats (Lewis) were transplanted with small bowel from ACI rats. Tacrolimus (Tac) was injected daily from days 0 to 4. Bone marrow cells of ACI rats were infused via the portal or tail vein on the day of surgery. On day 5, both GILs and PBLs collected from SBT graft and peripheral blood, respectively, were analyzed for intracellular cytokine production of recipient-derived alphabeta-T cells. The Th1/Th2 balance in each group was designated as the ratio of the percentage of GILs or PBLs staining positive for intracellular IL-4 or IFN-gamma, respectively. The total cell numbers of GILs from SBT graft were also counted.

RESULTS

Survival of recipients was markedly prolonged by the combination of Tac and donor-specific bone marrow infusion via the portal vein (DSBMI-PV-Tac) compared with the untreated control, Tac alone, or DSBMI tail vein plus Tac. DSBMI-PV-Tac significantly decreased the total cell numbers of GILs and also induced remarkable Th2-type response in GILs.

CONCLUSIONS

Our results indicate that DSBMI-PV-Tac decreased GILs and enhanced Th2-type response in SBT graft, both of which are associated with a significant prolongation of graft survival in SBT.

Tolerogenic protocols for intestinal transplantation

The intestine has long been considered as a "forbidden" organ to transplant [Ann. Surg. 216 (1992) 223-33]. This is due to the particularly challenging nature of the immunological conflict that an intestinal graft may cause: a particularly vigorous rejection response, in addition to the capacity to mount a graft-versus-host disease (GVHD) [Transplantation 37 (1984) 429]. Currently, the short-term success of intestinal transplantation (Itx) depends upon the chronic delivery of profound immunosuppression but this causes infection, malignancies--in particular posttransplant lymphoproliferative disorder (PTLD)--and direct drug toxicity. For these reasons, the results of Itx remain inferior to those of other solid organ transplants in the middle and in the long term (Intestinal Transplant Registry: www.small-bowel-transplant.org). Improved results and wider application of Itx requires the development of protocols that would facilitate acceptance of the new intestine thereby allowing to reduce the need for immunosuppression with its attending complications. Relevant experimental data and the recent evolution in the clinical strategies used to promote acceptance of intestinal grafts are reviewed.

Crossing the bridge: large animal models in translational transplantation research

Many methods for reducing the immunosuppressive requirements of allotransplantation have been proposed based on a growing understanding of physiological and allospecific immunity. As these regimens are developed for clinical application, they require validation in models that are reasonably predictive of their performance in humans. This article provides an overview of the large animal models commonly used to test immunomodulatory organ transplant protocols. The rationale for the use of large animals and the effects of common immunosuppressants in the dog, pig, and non-human primate are reviewed. Promising methods for the induction of allospecific tolerance are surveyed with references to early human trials where appropriate.

Auxiliary en-bloc liver-small bowel transplantation with partial pancreas preservation in pigs

AIM

The aim of this study was to describe an auxiliary combined liver-small bowel transplantation model with the preservation of duodenum, head of pancreas and hepatic biliary system in pigs. The technique, feasibility, security and immunosuppression were commented.

METHODS

Forty outbred long-white pigs were randomized into two groups, and the auxiliary composite liver/small bowel allotransplantations were undertaken in 10 long-white pigs in each group with the recipient liver preserved. Group A was not treated with immunosuppressive drugs while group B was treated with cyclosporine A and methylprednisolone after operation. The hemodynamic changes and amylase of body fluid (including blood, urine and abdominal drain) were analyzed.

RESULTS

The average survival time of the animals was 10+/-1.929 d (6 to 25 d) in group A while more than 30 d in group B. The pigs could tolerate the hemodynamic fluctuation during operation and the hemodynamic parameters recovered to normal 2 h after blood reperfusion. The transient high amylase level was decreased to normal one week after operation and autopsy showed no pancreatitis.

CONCLUSION

Auxiliary en-bloc liver-small bowel transplantation with partial pancreas preservation is a feasible and safe model with simplified surgical techniques for composite liver/small bowel transplantation. This model may be used as a preclinical training model for clinical transplantation method, clinical liver-small bowel transplantation related complication research, basic research including immunosuppressive treatment, organ preservation, acute rejection, chronic rejection, immuno-tolerance and xenotransplantation.

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.

IP-10-induced recruitment of CXCR3 host T cells is required for small bowel allograft rejection

BACKGROUND & AIMS

Chemokines mediate cell trafficking in inflammatory states such as allograft rejection. However, their role in small-bowel allograft rejection has not been defined. The aim of this study was to examine the roles of type 1 helper T-cell chemokines in small-bowel allograft rejection.

METHODS

Mucosal histology, chemokine messenger RNA (real-time polymerase chain reaction), and cell isolates were examined in small-bowel allografts and isografts. Interferon-gamma-inducible protein-10/CXC chemokine receptor (CXCR) 3 interactions were specifically evaluated by using allografts from interferon-gamma-inducible protein-10(-/-) donors and adoptive transfer of CXCR3(-/-) T cells into recombination activating gene (RAG)-1(-/-) recipients of small-bowel allografts.

RESULTS

Type 1 helper T-cell cytokine (interferon-gamma) and chemokine (interferon-gamma-inducible protein-10, monokine induced by interferon-gamma, macrophage-inflammatory protein-1 alpha, and regulated on activation, normal T cells expressed and secreted) messenger RNA up-regulation was detected (real-time polymerase chain reaction) by postoperative day 3 in small-bowel allografts. Interferon-gamma-inducible protein-10(+/+) small-bowel allograft rejection was associated with a dramatic (>7-fold) increase in CXCR3(+) host T cells in the graft lamina propria. With interferon-gamma-inducible protein-10(-/-) small-bowel allografts, CXCR3(+) host T-cell infiltration of the graft lamina propria was markedly decreased and rejection was significantly delayed. Whereas adoptive transfer of wild-type B6 (CXCR3(+/+)) T cells into B6 (RAG-1(-/-)) recipients induced rapid rejection of CB6F1 small-bowel allografts, rejection was significantly delayed (29.2 +/- 8.7 days vs. 16.5 +/- 3.1 days; P < 0.01) in B6 (RAG-1(-/-)) mice reconstituted with T cells from B6 (CXCR3(-/-)) mice.

CONCLUSIONS

Recruitment of CXCR3(+) host T cells by donor derived interferon-gamma-inducible protein-10 may precipitate small-bowel allograft rejection. These data highlight the importance of type 1 helper T cell-related chemokines in promoting cell-mediated rejection responses in small-bowel allografts and suggest that interferon-gamma-inducible protein-10 is an attractive therapeutic target for humanized monoclonal antibody strategies.

Management of venous access problems before and after intestinal transplantation: case reports

Patients suffering irreversible loss of intestinal function require total parenteral nutrition (TPN). During long-term TPN, catheter infections are a common problem and intestinal transplantation (ITx) is indicated when patients experience loss of venous access. We report two patients with short bowel syndrome--one before and one after ITx. The patient listed for ITx had several catheter infections with septic temperatures. Staphylococcus aureus, detected in blood cultures, was treated with vancomycin. Packing of the central venous line (CVL) with vancomycin was not successful; the CVL was changed. Search for an infectious focus identified a septic femoral head destruction that was treated by incision and implantation of a hip endoprothesis. Thereafter, the patient was free from infection. The second patient underwent ITx on January 2, 2003, and is free from TPN. ITx was complicated by temporary acute renal failure and heparin-induced thrombocytopenia (HIT) syndrome. After compensation of kidney function, the patient required additional saline solution (1 to 2 L/d) to optimize renal perfusion. A CVL was placed in the external iliac vein (EIV) due to previous loss of venous access. At 2 months after ITx, the CVL was infected and the patient was septic. MR scan revealed only one jugular vein to provide vascular access. Therefore, the CVL was changed from the right to the left EIV. Postoperatively, the patient developed thrombosis of right iliac vein and a wound infection that is probably related to the nearby graft ileostomy. At present, the patient is in good condition with a functioning graft. In conclusion, recurrent CVL infections before ITx might reflect other infectious foci that require intensive diagnostic evaluation. After ITx, CVL infection may cause venous thrombosis. Therefore, a single upper venous access should be preserved for optimal care.

Quality of life after pediatric intestinal transplantation: the perception of pediatric recipients and their parents

The objective was to examine the perception of physical and psychosocial functioning of pediatric intestinal transplant recipients who are beyond the perioperative period and compare these with normal and chronically ill children. Child and parent forms of the Child Health Questionnaire were administered to all 29 pediatric intestinal transplant recipients between the ages of 5 and 18 years who had had a small bowel transplantation 1 year previous and had a functional allograft. Comparison was made with published norms and scores for pediatric patients on hemodialysis. Intestinal transplant recipients (on average 5 years after intestinal transplantation and at a mean age 11 years) reported similar scores in all domains compared with normal children. Parents of intestinal transplant recipients noted decreased function in several domains related to their child's general health, physical functioning, and the impact of the illness on parental time, emotions and family activities. Intestinal transplant recipients beyond the perioperative period perceive their physical and psychosocial functioning as similar to normal school children. Parental proxy assessments differ from the recipients, with the parent's perception of decreased general health and physical functioning for intestinal transplant recipients compared with norms.

Pancreatic transplantation at the University of Pittsburgh

Campath-1H preconditioning with tacrolimus monotherapy is an effective immunosuppressive regimen for pancreas transplantation, with acceptable patient and graft survival rates early after transplantation. Rejection rates are low under this protocol if the tacrolimus level is kept consistently >10 ng/ml. This immunosuppressive protocol, combined with recent technical refinements, has resulted in lower rates of thrombosis and overall complications. Pancreatic transplantation en-bloc with visceral grafts has the following unique features: Diabetes is a rare indication, and HLA matching is not required. The gland is immunologically protected by the simultaneously transplanted visceral organs. Disease gravity, surgical complexity and gut alloimmunity influence the overall pancreatic allograft survival. The current UNOS listing criteria and data registry should be modified for obvious logistic and scientific reasons.

Laser-Doppler flowmetry is reliable for early diagnosis of small-bowel acute rejection in the mouse

The purpose of the study was to investigate intestinal mucosal perfusion in mouse small-bowel transplantation (SBT), using laser-Doppler flowmetry. Heterotopic SBT was performed in syngeneic and allogeneic combinations. Mucosal perfusion was measured both in the native and in the grafted intestine at time of surgery and at 1, 3, 6, and 8 days postoperatively. Histology specimens were obtained at the same time and graded for rejection. No rejection was seen in the syngeneic group at any of the time points studied. The allografts displayed significant decreased mucosal perfusion on postoperative days 3, 6, and 8. Rejection was histologically evident on postoperative days 6 and 8. Laser-Doppler perfusion in the rejecting intestinal allograft was decreased before onset of histological features of rejection. Mucosal blood flow measured by laser-Doppler could be used as an early indicator of acute rejection in SBT.

Surgical approaches and intestinal transplantation

The surgical treatment of short-bowel syndrome has been traditionally based on the correction of mechanical obstruction, which is responsible for bacterial overgrowth syndrome, or on intestinal expansion procedures. Since the introduction of clinical intestinal transplantation by Lillehei in 1964, there have been remarkable advances in the immunosuppressive regimens to control rejection and in preservation techniques, monitoring and critical care. Newer and more powerful immunosuppressants have helped to transform intestinal transplantation into a clinical reality-transplantation can now be a life-saving procedure for patients with intestinal failure. It is currently indicated in the event of life-threatening complications of an underlying disease or from total parenteral nutrition (TPN). Rehabilitation in successful cases is excellent.

Morphological changes on small-bowel fetal allografts in mice

The aim of this study was to evaluate the early morphological development and acute rejection process in fetal intestine allografts. Grafts from C57BL/6 fetal intestines were implanted in an avascular form in BALB/C recipients. A syngeneic group of animals was used to compare the evolution. The allogeneic recipients were distributed in 6 groups, according to the day of sacrifice (3rd, 4th, 5th, 6th, 7th, and 10th postoperational day (POD)) and the control group on the 2nd, 5th, and 7th POD. These grafts were stained with hematoxylin and eosin for histological evaluation, in agreement with the classification of Auber et al. (Chirurgie 123:122-130, 1998). Data showed a progressive development of the graft until POD 5. On POD 3 and 4, a top grade of development and an initial rejection were observed. From POD 5-7 and on POD 10, the acute rejection reaction was more important than the development process. The higher level of rejection was observed on POD 10, and it was similar to the 7th POD. Our results showed good graft development until POD 5. After that, the acute rejection response impeded analysis of the development process.

Intestinal transplantation

Advances in immunosuppressive treatment as well as better monitoring and control of acute rejection have brought intestinal transplantation (ITx) into the realm of standard treatment for permanent intestinal failure. The results from the intestinal Transplant International Registry (www.intestinaltransplant.org) indicate that ITx is currently an acceptable clinical modality for selected patients with permanent intestinal failure. The goal of this short review is to deal with indications, clinical results and complications of ITx. Although it has been used in humans for the past two decades, very few data are available regarding graft function and its monitoring.

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.

Modified technique for combined liver-small bowel transplantation in pigs

AIM

As the conventional combined liver-small bowel transplantation is complicated with many postoperative complications, the aim of this study was to describe a modified technique for the combined liver-small bowel transplantation with preservation of the duodenum, partial head of pancreas and hepatic biliary system in pigs.

METHODS

Composite liver/small bowel allotransplantations were undertaken in 30 long-white pigs. The graft included liver, about 3 to 4 m proximal jejunum, duodenum and partial pancreatic head. Vessels reconstructions included subhepatic vena cava-vena cava anastomosis, aorta-aorta anastomosis and portal-splenic vein anastomosis.

RESULTS

Without immunosuppressive treatment, the median survival time of the animals was 6 days (2 to 12 days), and about 76.9 % (20/26) of the animals survived for more than 4 days after operation.

CONCLUSION

The modified technique is feasible and safe for the composite liver/small bowel transplantation with duodenum and pancreas preserved in pigs. And also this technique can simplify the operation and decrease possible postoperative complications.

Exfoliative rejection after intestinal transplantation in children

BACKGROUND

Graft rejection is the most significant cause of allograft failure after intestinal transplantation (ITx). Severity can vary and is based on histologic criteria, the most extreme form being exfoliation of the mucosa. We present the characteristics and outcome of children who developed exfoliative rejection (ER) after ITx.

METHODS

Between June 1990 and March 2002, 88 patients received 92 ITx which included isolated small bowel (SB, n = 26), combined liver-small bowel (LSB, n = 54), and multivisceral MV n = 12) allografts performed under tacrolimus and steroid immunosuppresson. ER was diagnosed by endoscopy and confirmed by biopsy.

RESULTS

Thirteen (15%) of 88 patients developed 15 episodes of ER in 15 intestinal allografts, and included SB (n = 8), LSB (n = 5), and MV (n = 2). Time to ER after ITx ranged from 9 days to 45.5 months (median 22 days). Eight episodes of ER developed within 1 month after ITx. Ten episodes of ER were exacerbations of prior rejection. Five episodes occurred abruptly. All but one received OKT3. Fourteen of 15 allografts were lost; six patients underwent allograft enterectomy acutely as a salvage operation because of ER. The remainder of the allografts were either removed or lost to patient death as a consequence to infection or chronic rejection after resolution of ER. Retransplantation was performed in three patients, with subsequent recurrence of ER in two retransplanted allografts. Inclusion of a liver allograft was a protective factor toward decreasing the incidence of ER. The results of cross-matching, inclusion of a colonic segment, and simultaneous bone marrow infusion did not affect the incidence of ER. Infectious complications included post-transplant lymphoproliferative disease (n = 4), cytomegalovirus (n = 5), and adenovirus infection (n = 2).

CONCLUSIONS

Exfoliative rejection is associated with a high morbidity and mortality after ITx. Strategies to improve survival may include up front anti-lymphocyte antibody therapy and, when fail to respond promptly and satisfactorily, early intestinal allograft removal.

Management of complications in patients receiving home parenteral nutrition

Patients receiving long-term home parenteral nutrition tend to fall under the care of adult and pediatric gastroenterologists. This article reviews the management of potential infectious, mechanical and metabolic complications and describes common psychosocial issues related to the therapy. The point at which to refer the patient to an intestinal failure program offering autologous bowel reconstruction and small bowel transplantation is discussed.