Current status of pancreas transplantation:

Comparing Outcomes and Cost Between Pancreas Transplant and Standard of Care in Patients With Type 1 Diabetes

OBJECTIVES

Pancreas transplant is the only treatment that establishes normal glucose levels for patients diagnosed with diabetes. We analyzed the outcome of pancreas transplant alone (PTA) versus standard of care in the United States from 2008 to 2018. We also developed an economic model to analyze the cost-effectiveness of pancreas transplant versus continuing standard of care.

METHODS

We used the Scientific Registry of Transplant Recipients database and analyzed PTA recipient survival. Using those results, we developed a Markov model that followed a cohort of 40-year-old patients with type 1 diabetes over a 10-year time horizon. The primary outcomes were (i) the survival benefit of a pancreas transplant, (ii) quality-adjusted life-years (QALYs), and (iii) total costs.

RESULTS

We found no difference in survival advantage of PTA compared with standard of care (hazard ratio, 1.09; 95% confidence interval, 0.56-2.14). However, pancreas transplant ($172,823, 6.87 QALY) was cost-saving compared with standard of care ($232,897, 6.04 QALY) for type 1 diabetes. Pancreas transplantation was cost-effective in 95% of 10,000 simulations in probabilistic sensitivity analysis, using a $100,000/QALY willingness-to-pay threshold.

CONCLUSIONS

Although there is no difference in survival for PTA compared with standard of care, PTA is a cost-saving therapy for type 1 diabetes.

Technical factors that minimize the occurrence of early graft failure in pancreas transplantation

Pancreatic transplantation is the only treatment for insulin-dependent diabetes resulting in long-term euglycemia without exogenous insulin. However, pancreatic transplantation has become debatable following the improvements in the results of islet transplantation and artificial pancreas. Therefore, surgeons who perform pancreas transplants require the best surgical technique that can minimize technical failure. We aimed to report our experiences with pancreatic transplantations. We transplanted 65 pancreatic grafts between 2015 and 2020. Except for one death due to hypoxic brain damage after surgery, no postoperative technical failure was observed. We usually perform duodeno-duodenal anastomosis using the transperitoneal approach, with retrocolic placement of the graft pancreas. There was no leakage from the duodenum even after immunologic graft failure. To prevent venous thrombosis, which is the most common cause of technical failure, we used the inferior vena cava for anastomosis and added graft venoplasty with a patch of donor vena cava or aortic interposition graft to the bench procedure; subsequently, there were no cases of technical failure due to thrombosis post-transplantation. Therefore, the 1-year graft survival (insulin-free) rate was more than 95%. The improving the surgical technique will maintain pancreatic transplantation as the best treatment for insulin-dependent diabetes. This article is protected by copyright. All rights reserved.

Preoperative C-Peptide Predicts Weight Gain After Pancreas Transplantation

BACKGROUND

Transplant recipients are susceptible to cardiovascular complications, obesity, and increased insulin resistance after transplant. Here we assess weight gain in diabetic recipients after pancreas transplantation.

METHODS

This is a single-center study of 32 simultaneous pancreas and kidney and 5 pancreas after kidney transplant recipients from 2014 to 2018. Starting C-peptide levels ≤ 0.1 ng/mL were used to denote insulin nondetectability (n = 25) and C-peptide levels > 0.1 ng/mL as insulin detectability (n = 12). Hemoglobin A_1c, body mass index (BMI), and weight following transplantation were assessed.

RESULTS

Hemoglobin A_1c at 1 year was 5.9% in the insulin nondetectable recipients and 5.6% in the insulin detectable group (P = .56). Average BMI after transplant was higher in the insulin detectable group 28.6 versus 24.4 kg/m² (P = .03) despite no difference in starting BMIs (24.9 versus 24.0 kg/m², P = .42). The insulin detectable group also had a larger percentage weight change from their starting weight 13.1% versus 0.9 % at 1 year (P = .02). Linear regression demonstrated that starting C-peptide was a significant predictor of weight gain posttransplant.

CONCLUSIONS

Patients with elevated C-peptides at time of transplant are susceptible to rapid weight gain postoperatively. These patients may benefit from aggressive nutritional management.

Oxygenation strategies for encapsulated islet and beta cell transplants

Human allogeneic islet transplantation (ITx) is emerging as a promising treatment option for qualified patients with type 1 diabetes. However, widespread clinical application of allogeneic ITx is hindered by two critical barriers: the need for systemic immunosuppression and the limited supply of human islet tissue. Biocompatible, retrievable immunoisolation devices containing glucose-responsive insulin-secreting tissue may address both critical barriers by enabling the more effective and efficient use of allogeneic islets without immunosuppression in the near-term, and ultimately the use of a cell source with a virtually unlimited supply, such as human stem cell-derived β-cells or xenogeneic (porcine) islets with minimal or no immunosuppression. However, even though encapsulation methods have been developed and immunoprotection has been successfully tested in small and large animal models and to a limited extent in proof-of-concept clinical studies, the effective use of encapsulation approaches to convincingly and consistently treat diabetes in humans has yet to be demonstrated. There is increasing consensus that inadequate oxygen supply is a major factor limiting their clinical translation and routine implementation. Poor oxygenation negatively affects cell viability and β-cell function, and the problem is exacerbated with the high-density seeding required for reasonably-sized clinical encapsulation devices. Approaches for enhanced oxygen delivery to encapsulated tissues in implantable devices are therefore being actively developed and tested. This review summarizes fundamental aspects of islet microarchitecture and β-cell physiology as well as encapsulation approaches highlighting the need for adequate oxygenation; it also evaluates existing and emerging approaches for enhanced oxygen delivery to encapsulation devices, particularly with the advent of β-cell sources from stem cells that may enable the large-scale application of this approach.