Ten-year survival after simultaneous pancreas/kidney transplantation with bladder drainage and tacrolimus-based immunosuppression

Risk Factors for Type 1 Diabetes Recurrence in Immunosuppressed Recipients of Simultaneous Pancreas-Kidney Transplants

Patients with type 1 diabetes (T1D) who are recipients of pancreas transplants are believed to rarely develop T1D recurrence in the allograft if effectively immunosuppressed. We evaluated a cohort of 223 recipients of simultaneous pancreas-kidney allografts for T1D recurrence and its risk factors. With long-term follow-up, recurrence was observed in approximately 7% of patients. Comparing the therapeutic regimens employed in this cohort over time, lack of induction therapy was associated with recurrence, but this occurs even with the current regimen, which includes induction; there was no influence of maintenance regimens. Longitudinal testing for T1D-associated autoantibodies identified autoantibody positivity, number of autoantibodies, and autoantibody conversion after transplantation as critical risk factors. Autoantibodies to the zinc transporter 8 had the strongest and closest temporal association with recurrence, which was not explained by genetically encoded amino acid sequence donor-recipient mismatches for this autoantigen. Genetic risk factors included the presence of the T1D-predisposing HLA-DR3/DR4 genotype in the recipient and donor-recipient sharing of HLA-DR alleles, especially HLA-DR3. Thus, T1D recurrence is not uncommon and is developing in patients treated with current immunosuppression. The risk factors identified in this study can be assessed in the transplant clinic to identify recurrent T1D and may lead to therapeutic advances.

Lessons From Pancreas Transplantation in Type 1 Diabetes: Recurrence of Islet Autoimmunity

Type 1 diabetes recurrence (T1DR) affecting pancreas transplants was first reported in recipients of living-related pancreas grafts from twins or HLA identical siblings; given HLA identity, recipients received no or minimal immunosuppression. This observation provided critical evidence that type 1 diabetes (T1D) is an autoimmune disease. However, T1DR is traditionally considered very rare in immunosuppressed recipients of pancreas grafts from organ donors, representing the majority of recipients, and immunological graft failures are ascribed to chronic rejection. We have been performing simultaneous pancreas-kidney (SPK) transplants for over 25 years and find that 6-8 % of our recipients develop T1DR, with symptoms usually becoming manifest on extended follow-up. T1DR is typically characterized by (1) variable degree of insulitis and loss of insulin staining, on pancreas transplant biopsy (with most often absent), minimal to moderate and rarely severe pancreas, and/or kidney transplant rejection; (2) the conversion of T1D-associated autoantibodies (to the autoantigens GAD65, IA-2, and ZnT8), preceding hyperglycemia by a variable length of time; and (3) the presence of autoreactive T cells in the peripheral blood, pancreas transplant, and/or peripancreatic transplant lymph nodes. There is no therapeutic regimen that so far has controlled the progression of islet autoimmunity, even when additional immunosuppression was added to the ongoing chronic regimens; we hope that further studies and, in particular, in-depth analysis of pancreas transplant biopsies with recurrent diabetes will help identify more effective therapeutic approaches.

Type 2 diabetes: is pancreas transplantation an option?

Transplantation of the whole vascularized pancreas can provide insulin secretion in patients with insulin-dependent, type 1 diabetes mellitus (T1D). It restores euglycemia in most patients, with the potential to impact the chronic diabetic complications and quality of life. Pancreas transplantation (PT) is presently controversial for type 2 diabetes mellitus (T2D). For those patients with severe glycemic dysregulation, T2D can be associated with the same life-threatening sequelae as T1D such as severe hypoglycemia and kidney failure that could be corrected by pancreas (and kidney) transplantation. Thus, clinical indications and patient selection criteria are very important. This chapter will review the current status of PT for T2D and discuss the options and evolution of transplant perspectives.

Retrospective assessment of islet cell autoantibodies in pancreas organ donors

OBJECTIVE

Of deceased pancreas donors, 3-4% may have autoantibodies (AAb) to pancreatic islet cell antigens; these autoantibodies are well-established markers of type 1 diabetes. We investigated whether donor AAb positivity could affect the outcome of pancreas transplantation.

RESEARCH DESIGN AND METHODS

We retrospectively tested AAb in 135 donors whose pancreata and kidneys were transplanted in type 1 diabetes patients. We measured AAb to glutamic acid decarboxylase (GAD-AAb), the tyrosine-phosphatase-like protein IA2 (IA2-AAb), and insulin (insulin-AAb). We then evaluated pancreas transplant outcome data.

RESULTS

Four of 135 (2.96%) donors were AAb positive: three donors had GAD-AAb, and one donor had insulin-AAb. Their respective recipients became insulin independent on follow-up. Three of the four recipients had normal, insulin-producing grafts 3-5.8 years after transplant. The recipient of the insulin-AAb-positive donor pancreas developed chronic rejection following discontinuation of immunosuppression 3.3 years after transplant.

CONCLUSIONS

Single AAb positivity did not affect the outcome of pancreas transplantation in our study.

Hypercoagulable state associated with kidney-pancreas transplantation. Thromboelastogram-directed anti-coagulation and implications for future therapy

BACKGROUND

The clinical consequences of type 1 diabetes mellitus (IDDM) include diabetic triopathy: retinopathy, nephropathy, and neuropathy, as well as microangiopathy, accelerated atherosclerotic disease, and hypercoagulability. The etiology of the hypercoagulability is multifactorial, involving various clotting factors or pathways (for example platelets, fibrinogen, individual components of the clotting system and/or fibrinolysis in different studies). The development of end-stage renal disease (ESRD), with the uremia-related platelet effect has the potential to protect from the existing hypercoagulable state. This has important implications for surgery, particularly simultaneous pancreas-kidney (SPK) transplantation, where the pancreas has historically been prone to thrombosis. This has led us to perform intra-operative thromboelastograms (TEG's) to evaluate the patient's current coagulation status.

METHODS

A TEG was performed in 85 SPK recipients along with a control group of 54 non-diabetic kidney transplant (KT) recipients.

RESULTS

For each of the 4 TEG coagulation parameters, the SPK recipients were significantly more hypercoagulable than the non-diabetic KT recipients. The use of intra-operative heparin is based on the degree of hypercoagulability by TEG and degree of operative hemostasis. There has been one PT lost to thrombosis (1%) in the first week following transplantation during this time.

CONCLUSION

The use of TEG is a helpful adjunct to SPK surgery, demonstrating the patient's current coagulation status. Nearly all SPK recipients (type 1 IDDM with ESRD) have been demonstrated to be hypercoagulable. The TEG allows the judicious use of anti-coagulation at the time of surgery, and beyond.

Advances in pancreas transplantation

Despite early obstacles impacting the success of pancreatic transplantation, the introduction of new procedures and new immunosuppressive therapies during the past 2 decades has improved outcomes for pancreatic transplant recipients. For example, the use of bladder drainage and better human leukocyte antigen matching has helped overcome some of the early obstacles of pancreatic transplantation. In addition, the introduction of tacrolimus in 1994 and mycophenolate mofetil in 1996 has helped lower rates of acute rejection and increase graft survival, with less nephrotoxicity than treatment with cyclosporine. Regimens allowing the tapering of corticosteroids have also helped reduce the rates of acute pancreas rejection. To further improve therapeutic options for patients with type 1 diabetes or end-stage renal disease, pancreatic islet transplantation and organ and islet xenotransplantation should be further explored.

Vascular complications of pancreas transplantation

OBJECTIVE

The purpose of our study was to focus on the early diagnosis and treatment of vascular complications after simultaneous pancreas-kidney (SPK) transplantation. Description of the technique for salvage of the graft after venous thrombosis (VT) is also provided.

METHODS

From July 1994 to December 2002, 14 patients of 206 SPK transplant recipients had partial VT. Partial splenic VT (PSVT) was documented in 10 patients (4.8%), two had complete thrombosis of the splenic vein, one partial superior mesenteric thrombosis, and one developed partial thrombosis of the splenic and superior mesenteric vein. Four patients developed complete VT of the pancreas allograft and one superior mesenteric artery thrombosis. Our experience with four arteriovenous fistulae is also reported. The immunosuppression included tacrolimus, steroids, and monoclonal antibody to the IL-2 receptor. Thymoglobulin was introduced in June 2000 in our protocol combined with rapamycin or mycophenolate mofetil. These cases were identified following the intravenous (iv) use of tacrolimus with or without anti-IL-2R therapy. One case of complete VT is also reported one month following transplantation in a recipient with high rapamycin levels. Diagnosis was established during routine color Doppler ultrasonography.

RESULTS

Partial VT was effectively treated with anticoagulation. Complete VT required surgical thrombectomy. In our series, the pancreas was salvaged successfully in all patients with the technique described here.

CONCLUSION

Early diagnosis of vascular complications after pancreas transplantation is of paramount importance for the appropriate treatment with organ salvage. Based on our experience, we suggest that VT can be effectively treated with anticoagulation. Aspirin is sufficient for PSVT.

Simultaneous pancreas-kidney transplantation in Jehovah's Witness patients

The safety and efficacy of renal and liver transplantation has been reported for Jehovah's Witness (JW) patients, with patient, and graft survival similar to that of non-JW patients. We report our experience in five JW recipients of simultaneous pancreas-kidney transplants. None of the patients received transfusion of blood or blood products, either before or after transplant. Like the other solid organ transplants, patient, and graft survival was similar to that of the non-JW group. Specific technical issues related to the operative procedure include the use of the cell saver until the donor duodenum is opened (enteric contamination). Post-operatively, care should be taken to minimize drawing of blood and optimize erythrocyte synthesis with erythropoetin, folic acid, vitamin B12, and iron. Finally, it is critical that the pre-operative evaluation demonstrates sufficient cardiac reserve to allow the JW patient to tolerate a possible temporary anemic state.