Pushing the envelope: living donor pancreas transplantation

Pancreatic Transplantation: Surgical Anatomy and Complications

Pancreatic transplantation is a complex surgical procedure performed for patients with chronic severe diabetes, often performed in combination with renal transplantation. Vascular and exocrine drainage anatomy varies depending on the surgical technique. Radiology plays a critical role in the diagnosis of postoperative complications, requiring an understanding of grayscale/Doppler ultrasound as well as computed tomography and MR imaging. In this review, we detail usual surgical methods and normal postoperative imaging appearances. We then review the most common complications following pancreatic transplants, emphasizing diagnostic features of vascular (arterial/venous), surgical, and diffuse parenchymal pathologic conditions on multiple imaging modalities.

First World Consensus Conference on pancreas transplantation: Part II - recommendations

The First World Consensus Conference on Pancreas Transplantation provided 49 jury deliberations regarding the impact of pancreas transplantation on the treatment of diabetic patients, and 110 experts' recommendations for the practice of pancreas transplantation. The main message from this consensus conference is that both simultaneous pancreas-kidney transplantation (SPK) and pancreas transplantation alone can improve long-term patient survival, and all types of pancreas transplantation dramatically improve the quality of life of recipients. Pancreas transplantation may also improve the course of chronic complications of diabetes, depending on their severity. Therefore, the advantages of pancreas transplantation appear to clearly surpass potential disadvantages. Pancreas after kidney transplantation increases the risk of mortality only in the early period after transplantation, but is associated with improved life expectancy thereafter. Additionally, preemptive SPK, when compared to SPK performed in patients undergoing dialysis, appears to be associated with improved outcomes. Time on dialysis has negative prognostic implications in SPK recipients. Increased long-term survival, improvement in the course of diabetic complications, and amelioration of quality of life justify preferential allocation of kidney grafts to SPK recipients. Audience discussions and live voting are available online at the following URL address: http://mediaeventi.unipi.it/category/1st-world-consensus-conference-of-pancreas-transplantation/246.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

β Cell Replacement Therapy: The Next 10 Years

β cell replacement with either pancreas or islet transplantation has progressed immensely over the last decades with current 1- and 5-year insulin independence rates of approximately 85% and 50%, respectively. Recent advances are largely attributed to improvements in immunosuppressive regimen, donor selection, and surgical technique. However, both strategies are compromised by a scarce donor source. Xenotransplantation offers a potential solution by providing a theoretically unlimited supply of islets, but clinical application has been limited by concerns for a potent immune response against xenogeneic tissue. β cell clusters derived from embryonic or induced pluripotent stem cells represent another promising unlimited source of insulin producing cells, but clinical application is pending further advances in the function of the β cell like clusters. Exciting developments and rapid progress in all areas of β cell replacement prompted a lively debate by members of the young investigator committee of the International Pancreas and Islet Transplant Association at the 15th International Pancreas and Islet Transplant Association Congress in Melbourne and at the 26th international congress of The Transplant Society in Hong Kong. This international group of young investigators debated which modality of β cell replacement would predominate the landscape in 10 years, and their arguments are summarized here.

Protocol Duodenal Graft Biopsies Aid Pancreas Graft Surveillance

BACKGROUND

Histological evaluation of the pancreas graft is usually done on demand resulting in significant delays. This analysis reports on endoscopic protocol duodenal graft biopsies at regular intervals to determine feasibility, safety, and monitoring benefits.

METHODS

Protocol duodenal graft biopsies in 27 consecutive pancreas transplants (10 simultaneous pancreas kidney [SPK], 17 pancreas after kidney [PAK]) with a follow-up of a minimum of 12 months were performed at days 14, 30, 90, 180, 360, 430. University of Pittsburgh Medical Center classification for intestinal rejection was used. C4d staining was performed when antibody-mediated rejection was suspected.

RESULTS

Overall patient and pancreas graft survival was 100% and 93% at a mean follow-up of 2.8 years. One hundred sixty-seven endoscopic biopsy procedures were performed in 27 grafts without any complication. Biopsies revealed rejection in 3 (30%) SPK recipients and in 15 (82%) of PAK recipients as early as 14 days posttransplant. Two patients underwent PAK retransplantation diagnosed with acute rejection at day 180. All except 1 recipient being treated for rejection, showed histological improvement following antirejection treatment. Following transient treatment success, a total of 3 pancreas grafts were lost for immunological reason. One loss was immediate despite antirejection treatment, 1 secondary to nonresolving rejection at 7 months and the third due to recurrent rejection 15 months posttransplantation. Additionally, biopsies detected vascular (venous thrombosis) and overimmunosuppression (cytomegalovirus infection) complications.

CONCLUSIONS

Protocol graft duodenal biopsies detect complications after whole-organ pancreas transplantation, are useful in guiding therapy, and carry potential for improving outcome.

Diabetes Mellitus in Living Pancreas Donors: Use of Integrated National Registry and Pharmacy Claims Data to Characterize Donation-Related Health Outcomes

BACKGROUND

Living donor pancreas transplant is a potential treatment for diabetic patients with end-organ complications. Although early surgical risks of donation have been reported, long-term medical outcomes in living pancreas donors are not known.

METHODS

We integrated national Scientific Registry of Transplant Recipients data (1987-2015) with records from a nationwide pharmacy claims warehouse (2005-2015) to examine prescriptions for diabetes medications and supplies as a measure of postdonation diabetes mellitus. To compare outcomes in controls with baseline good health, we matched living pancreas donors to living kidney donors (1:3) by demographic traits and year of donation.

RESULTS

Among 73 pancreas donors in the study period, 45 were identified in the pharmacy database: 62% women, 84% white, and 80% relatives of the recipient. Over a mean postdonation follow-up period of 16.3 years, 26.7% of pancreas donors filled prescriptions for diabetes treatments, compared with 5.9% of kidney donors (odds ratio, 4.13; 95% confidence interval, 1.91-8.93; P = 0.0003). Use of insulin (11.1% vs 0%) and oral agents (20.0% vs 5.9%; odds ratio, 4.50, 95% confidence interval, 2.09-9.68; P = 0.0001) was also higher in pancreas donors.

CONCLUSIONS

Diabetes is more common after living pancreas donation than after living kidney donation, supporting clinical consequences from reduced endocrine reserve.

Long-term Outcomes for Living Pancreas Donors in the Modern Era

BACKGROUND

Living donor segmental pancreas transplants (LDSPTx) have been performed selectively to offer a preemptive transplant option for simultaneous pancreas-kidney recipients and to perform a single operation decreasing the cost of pancreas after kidney transplant. For solitary pancreas transplants, this option historically provided a better immunologic match. Although short-term donor outcomes have been documented, there are no long-term studies.

METHODS

We studied postdonation outcomes in 46 segmental pancreas living donors. Surgical complications, risk factors (RF) for development of diabetes mellitus (DM) and quality of life were studied. A risk stratification model (RSM) for DM was created using predonation and postdonation RFs. Recipient outcomes were analyzed.

RESULTS

Between January 1, 1994 and May 1, 2013, 46 LDSPTx were performed. Intraoperatively, 5 (11%) donors received transfusion. Overall, 9 (20%) donors underwent splenectomy. Postoperative complications included: 6 (13%) peripancreatic fluid collections and 2 (4%) pancreatitis episodes. Postdonation, DM requiring oral hypoglycemics was diagnosed in 7 (15%) donors and insulin-dependent DM in 5 (11%) donors. RSM with three predonation RFs (oral glucose tolerance test, basal insulin, fasting plasma glucose) and 1 postdonation RF, greater than 15% increase in body mass index from preoperative (Δ body mass index >15), predicted 12 (100%) donors that developed postdonation DM. Quality of life was not significantly affected by donation. Mean graft survival was 9.5 (±4.4) years from donors without and 9.6 (±5.4) years from donors with postdonation DM.

CONCLUSIONS

LDSPTx can be performed with good recipient outcomes. The donation is associated with donor morbidity including impaired glucose control. Donor morbidity can be minimized by using RSM and predonation counseling on life style modifications postdonation.

Tolerance of Vascularized Islet-Kidney Transplants in Rhesus Monkeys

We previously reported that transplantation (Tx) of prevascularized donor islets as composite islet-kidneys (IK) reversed diabetic hyperglycemia in both miniature swine and baboons. In order to enhance this strategy's potential clinical applicability, we have now combined this approach with hematopoietic stem cell (HSC) Tx in an attempt to induce tolerance in nonhuman primates. IKs were prepared by isolating islets from 70% partial pancreatectomies and injecting them beneath the autologous renal capsule of five rhesus monkey donors at least 3 months before allogeneic IK Tx. HSC Tx was performed after mobilization and leukapheresis of the donors and conditioning of the recipients with total body irradiation, T cell depletion, and cyclosporine. One IK was harvested for histologic analysis and four were transplanted into diabetic recipients. IK Tx was performed either 20-22 (n = 3) or 208 (n = 1) days after HSC Tx. All animals accepted IKs without rejection. All recipients required >20 U/day insulin before IK Tx to maintain <200 mg/dL, whereas after IK Tx, three animals required minimal doses of insulin (1-3 U/day) and one animal was insulin free. These results constitute a proof-of-principle that this IK tolerance strategy may provide a cure for both end-stage renal disease and diabetes without the need for immunosuppression.

Pancreas Transplantation From Living Donors: A Single Center Experience of 20 Cases

Living donor pancreas transplantation (LDPT) has several advantages over deceased donor pancreas transplantation (DDPT), including better HLA matching, shorter ischemic time, and shorter waiting time. It remains an attractive option for diabetes mellitus (DM) patients with end stage renal disease. We reviewed 20 cases of LDPT performed in Asan Medical Center between October 1992 and March 2015. Six cases (30%) were pancreas transplantation alone (PTA), and the rest (70%) were simultaneous pancreas and kidney transplantation (SPK). Relations of donor and recipient were parents in 7 (35%), siblings in 6 (30%), spouse in 6 (30%), and cousin in 1 (5%). Graft survival in SPK at 1, 3, 5, and 10 years was 91.7%, 83.3%, 83.3%, and 83.3%, respectively, and that in PTA recipients was 50%, 33.3%, 16.7%, and 16.7%, respectively (p = 0.005). Causes of graft failure in SPK were thrombosis (one case), and rejection (one case), whereas those in PTA were noncompliance (two cases), thrombosis (one case), reflux pancreatitis (one case), and chronic rejection (one case). In terms of pancreas exocrine drainage, two grafts (25%) maintained their function in bladder drainage, while all grafts maintained in enteric drainage p < 0.05). Seven (35%) donors experienced minor pancreatic juice leakage and one underwent reoperation due to postoperative hematoma. Most donors maintained normoglycemia and normal renal function. However, two donors developed DM (at 1 and 90 months postdonation), and were treated with oral hypoglycemic agents. Graft survival in PTA recipients was poorer than in SPK due to poor compliance and bladder drainage-related problems. The surgical and metabolic complication rates of donors can be minimized by applying strict donor criteria. Therefore, LDPT with enteric drainage is an acceptable treatment for SPK.

Pancreas transplantation: solid organ and islet

Transplantation of the pancreas, either as a solid organ or as isolated islets of Langerhans, is indicated in a small proportion of patients with insulin-dependent diabetes in whom severe complications develop, particularly severe glycemic instability and progressive secondary complications (usually renal failure). The potential to reverse diabetes has to be balanced against the morbidity of long-term immunosuppression. For a patient with renal failure, the treatment of choice is often a simultaneous transplant of the pancreas and kidney (SPK), whereas for a patient with glycemic instability, specifically hypoglycemic unawareness, the choice between a solid organ and an islet transplant has to be individual to the patient. Results of SPK transplantation are comparable to other solid-organ transplants (kidney, liver, heart) and there is evidence of improved quality of life and life expectancy, but the results of solitary pancreas transplantation and islets are inferior with respect to graft survival. There is some evidence of benefit with respect to the progression of secondary diabetic complications in patients with functioning transplants for several years.

Treating diabetes with islet transplantation: lessons from the past decade in Lille

Type 1 diabetes (T1D) is due to the loss of both beta-cell insulin secretion and glucose sensing, leading to glucose variability and a lack of predictability, a daily issue for patients. Guidelines for the treatment of T1D have become stricter as results from the Diabetes Control and Complications Trial (DCCT) demonstrated the close relationship between microangiopathy and HbA1c levels. In this regard, glucometers, ambulatory continuous glucose monitoring, and subcutaneous and intraperitoneal pumps have been major developments in the management of glucose imbalance. Besides this technological approach, islet transplantation (IT) has emerged as an acceptable safe procedure with results that continue to improve. Research in the last decade of the 20th century focused on the feasibility of islet isolation and transplantation and, since 2000, the success and reproducibility of the Edmonton protocol have been proven, and the mid-term (5-year) benefit-risk ratio evaluated. Currently, a 5-year 50% rate of insulin independence can be expected, with stabilization of microangiopathy and macroangiopathy, but the possible side-effects of immunosuppressants, limited availability of islets and still limited duration of insulin independence restrict the procedure to cases of brittle diabetes in patients who are not overweight or have no associated insulin resistance. However, various prognostic factors have been identified that may extend islet graft survival and reduce the number of islet injections required; these include graft quality, autoimmunity, immunosuppressant regimen and non-specific inflammatory reactions. Finally, alternative injection sites and unlimited sources of islets are likely to make IT a routine procedure in the future.

Design of a bioartificial pancreas

Islet transplantation has been shown to be a viable treatment option for patients afflicted with type 1 diabetes. However, the lack of availablity of human pancreases and the need to use risky immunosuppressive drugs to prevent transplant rejection remain two major obstacles to the routine use of islet transplantation in diabetic patients. Successful development of a bioartificial pancreas using the approach of microencapsulation with perm-selective coating of islets in hydrogels for graft immunoisolation holds tremendous promise for diabetic patients because it has great potential to overcome these two barriers. In this review article, we will discuss the need for a bioartificial pancreas, provide a detailed description of the microencapsulation process, and review the status of the technology in clinical development. We will also critically review the various factors that will need to be taken into consideration in order to achieve the ultimate goal of routine clinical application.

Follow-up of secondary diabetic complications after pancreas transplantation

PURPOSE OF REVIEW

Successful pancreas transplantation restores physiologic glycemic and metabolic control. Its effects on overall patient survival (especially for simultaneous pancreas-kidney transplantation) are clear-cut. We herein review the available literature to define the impact of pancreas transplantation on chronic complications of diabetes mellitus.

RECENT FINDINGS

With longer-term follow-up, wider patient populations, and more accurate investigational tools (clinical and functional tests, noninvasive imaging, histology, and molecular biology), growing data show that successful pancreas transplantation may slow the progression, stabilize, and even favor the regression of secondary complications of diabetes, both microvascular and macrovascular, in a relevant proportion of recipients.

SUMMARY

Patients who are referred for pancreas transplantation usually suffer from advanced chronic complications of diabetes, which have classically been deemed irreversible. A successful pancreas transplantation is often able to slow the progression, stabilize, and even reverse many microvascular and macrovascular complications of diabetes. Growing clinical evidence shows that the expected natural history of long-term diabetic complications can be significantly modified by successful pancreas transplantation.

Innovations in organ donation

The growing disparity between organ availability for transplantation and the number of patients in need has challenged the donation and transplantation community of practice to develop innovative processes, ideas, and techniques to bridge the gaps. Advances in the sharing of best practices in the donation community have contributed greatly over the last 8 years. Broader sharing of updated guidelines for declaration of brain death in conjunction with improvements in deceased donor management have increased opportunities for organ donation. New techniques for organ preservation and organ resuscitation have allowed for better utilization of the potential donor pool. This review will highlight processes, ideas, and techniques in organ donation.

Transplantation of the pancreas

Pancreas transplantation consistently induces insulin-independence in beta-cell-penic diabetic patients, but at the cost of major surgery and life-long immunosuppression. One year after grafting, patient survival rate now exceeds 95 % across recipient categories, while insulin independence is maintained in some 85 % of simultaneous pancreas and kidney recipients and in nearly 80 % of solitary pancreas transplant recipients. The half-life of the pancreas graft currently averages 16.7 years, being the longest among extrarenal grafts, and substantially matching the one of renal grafts from deceased donors. The difference between expected (100 %) and actual insulin-independence rate is mostly explained by technical failure in the postoperative phase, and rejection in the long-term period. Death with a functioning graft remains a further major issue, especially in uremic patients who have undergone prolonged periods of dialysis. Refinements in graft preservation, surgical techniques, immunosuppression, and prophylactic treatments are expected to further improve the results of pancreas transplantation.