Pancreas transplant alone

The Pancreas After Kidney Transplant is a Competitive Option, Comparable to the Simultaneous Pancreas and Kidney Transplant

BACKGROUND

Simultaneous pancreas and kidney transplant (SPK) is the most common type of pancreas transplant performed worldwide. In contrast, there are a few drawbacks to pancreas after kidney transplant (PAK), such as the requirement for an additional operation, the immunologic risk, etc. SPK is the best option, but because of a lack of deceased donors and a lengthy waiting period, it is not always possible to use it.

METHODS

From 2015 to 2022, we performed 23 SPKs and 21 PAKs at the Pusan National University Yangsan Hospital in Korea. We compared the findings of PAK and SPK conducted within the same time period.

RESULTS

The waiting time for pancreatic graft was significantly shorter in the PAK than SPK group (345 days vs 1350 days, P ≤ .001). Throughout the monitoring period, just 1 pancreatic graft was lost in patients who underwent PAK, and the 7-year graft survival was 95%, with no statistically significant difference compared to SPK (90.3%, P = .600). Moreover, the graft survival of SPK or PAK was superior to that of pancreatic transplant alone (63.7%, P = .016). Only 1 pancreatic graft loss was a case of mortality with a functioning graft. No additional kidney transplant loss was observed in PAK recipients. There was no variation in creatinine levels between the pretransplant and posttransplant periods. There were 2 incidents of pancreatic graft and kidney graft rejection, respectively, but the grafts entirely recovered following rejection treatment.

CONCLUSION

According to our experiences, PAK could be another best choice for individuals with diabetic end-stage renal disease, especially in cases where deceased donors were severely deficient but living donor kidney transplants were actively performed in countries like Korea.

A New Mouse Model of Whole Pancreas Transplant With Graft Blood Through the Portal Vein

OBJECTIVES

Pancreas transplant is currently the most effective method for maintaining physiological blood sugar levels and reversing small blood vessel injuries. Our team developed a model of whole pancreas transplant based on microsurgical techniques following the investigation of more than 300 mice.

MATERIALS AND METHODS

A mouse pancreatic transplant model is required to investigate the pathophysiological process of pancreas transplant and pancreatic preservation technologies. Recently, the segment-neck pancreas transplant has been the most utilized mouse pancreatic transplant model. The innovative mouse pancreatic transplant modelthat we developed in this study uses the whole pancreas and returns heart blood flow into the liver via the portal vein.

RESULTS

With our mouse pancreatic transplant model, the survivalrate of mice aftertransplant was >80%, and the success rate of pancreatic transplant was >90%.

CONCLUSIONS

The segment-neck and the whole pancreas model can guarantee that the transplanted pancreas functions effectively, and both have excellent postoperative outcomes, survivalrates and pancreatic active rates.

Pancreas Transplant Alone in the USA, Where Do We Stand?

BACKGROUND

Currently, over 63,000 pancreas transplant procedures have been performed worldwide, with only approximately 8% of all pancreas transplants having been a pancreas transplant alone. Our study aimed to quantify outcomes following pancreas transplant alone in the United States from 2001 to 2020, with an emphasis on graft and patient survival.

METHODS AND MATERIALS

We performed a retrospective registry analysis utilizing the OPTN/UNOS database for pancreas transplants alone performed in the United States from January 2001 to May 2020 to assess transplant outcomes. The study population was divided into two subgroups: patients receiving a pancreas transplant between 2000 and 2009 and those receiving a pancreas transplant between 2010 and 2020.

RESULTS

3008 allograft recipients were included in the study. 1679 (54.87%) transplants were done from January 2000 to the end of 2009. 1381 (45.13%) transplants were done from 2010 to May 2020. Although the BMI and recipient sex comparison indicate a statistically significant difference, the differences are not clinically significant. The overall 5-year allograft survival rate was 52.17% in the 2000-2009 group, which increased to 58.82% in pancreas transplants alone from 2010 to 2020 (P = 0.02). The overall 5-year patient survival rate was 74.52% in the 2000-2009 group, which increased to 74.92% in pancreas transplants alone from 2010 to 2020 (P = 0.81).

CONCLUSION

With all the progress in terms of surgical techniques, organ allocation and preservation, and immunosuppressive regimens, the pancreas transplant alone allograft survival has been improving over the years, although it has been still being underutilized around the US.

Thromboinflammatory response is increased in pancreas transplant alone versus simultaneous pancreas-kidney transplantation and early pancreas graft thrombosis is associated with complement activation

Background

Pancreas transplant alone (PTA) recipients are more affected by pancreas graft thrombosis, and graft loss compared to simultaneous pancreas-kidney (SPK) recipients. The pathophysiology is unknown, but an increased immune response has been suggested in the PTA recipients. In this observational study, we compared perioperative thromboinflammation between PTA (n=32) and SPK (n=35) recipients, and between PTA recipients with (n=14) versus without (n=18) early graft thrombosis.

Methods

We measured C-reactive protein (CRP), plasma markers of activated coagulation and complement, and cytokines preoperatively and daily during the first postoperative week.

Results

Preoperatively, coagulation and complement activation markers were comparable between PTA and SPK recipients, while cytokine concentrations were higher in SPK recipients (TNF, IL-8, IP-10, MCP-1, MIP-1α; all p<0.05). On the first postoperative day, PTA recipients had higher coagulation activation, measured as thrombin-antithrombin complex (TAT), than SPK recipients (p=0.008). In the first postoperative week, PTA recipients showed higher relative cytokine release (IL-6, IL-8, G-CSF, IP-10, MCP-1, and MIP-1α; all p<0.05) while SPK recipients showed higher absolute cytokine concentrations (TNF, IL-1ra, IL-8, MIP-1α, and IL-4; all p<0.05). PTA and SPK recipients showed similar terminal complement complex (TCC, sC5b-9) activation. On the first postoperative day, TCC (OR 1.2 [95% CI 1.0-1.5] for 0.1 CAU/ml increase, p=0.02) and CRP (OR 1.2 [95% CI 1.0-1.3] for 10 mg/L increase, p=0.04) were associated with an increased risk of early graft thrombosis. TCC was specific for graft thrombosis, while CRP increased with several complications. PTA recipients with compared to those without graft thrombosis had higher TCC pre- (p=0.04) and postoperatively (p=0.03).

Conclusion

The relative increase in postoperative thromboinflammatory response was more pronounced in PTA recipients. Complement activation was associated with an increased risk of graft thrombosis. This study indicates that innate immune activation rather than elevated levels may affect early postoperative pancreas graft thrombosis.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT01957696, identifier NCT01957696

Pancreas Transplantation: Current Challenges, Considerations, and Controversies

Pancreas transplantation (PTx) reestablishes an autoregulating source of endogenous insulin responsive to normal feedback controls. In addition to achieving complete β-cell replacement that frees the patient with diabetes from the need to monitor serum glucose and administer exogenous insulin, successful PTx provides counterregulatory hormone secretion and exocrine function. A functioning PTx mitigates glycemic variability, eliminates the daily stigma and burden of diabetes, restores normal glucose homeostasis in patients with complicated diabetes, and improves quality of life and life expectancy. The tradeoff is that it entails a major surgical procedure and requisite long-term immunosuppression. Despite the high likelihood of rendering patients euglycemic independent of exogenous insulin, PTx is considered a treatment rather than a cure. In spite of steadily improving outcomes in each successive era coupled with expansion of recipient selection criteria to include patients with a type 2 diabetes phenotype, a decline in PTx activity has occurred in the new millennium related to a number of factors including: (1) lack of a primary referral source and general acceptance by the diabetes care community; (2) absence of consensus criteria; and (3) access, education, and resource issues within the transplant community. In the author's experience, patients who present as potential candidates for PTx have felt as though they needed to circumvent the conventional diabetes care model to gain access to transplant options. PTx should be featured more prominently in the management algorithms for patients with insulin requiring diabetes who are failing exogenous insulin therapy or experiencing progressive diabetic complications regardless of diabetes type. Furthermore, all patients with diabetes and chronic kidney disease should undergo consideration for simultaneous pancreas-kidney transplantation independent of geography or location.

Modern indications for referral for kidney and pancreas transplantation

PURPOSE OF REVIEW

Pancreas transplantation (PTx) is currently the only therapy that can predictably achieve sustained euglycemia independent of exogenous insulin administration in patients with insulin-dependent diabetes mellitus. This procedure involves a complex abdominal operation and lifetime dependence on immunosuppressive medications. Therefore, PTx is most frequently performed in combination with other organs, usually a kidney transplant for end stage diabetic nephropathy. Less frequently, solitary PTx may be indicated in patients with potentially life-threatening complications of diabetes mellitus. There remains confusion and misperceptions regarding indications and timing of patient referral for PTx.

RECENT FINDINGS

In this review, the referral, evaluation, and listing process for PTx is described, including a detailed discussion of candidate assessment, indications, contraindications, and outcomes.

SUMMARY

Because the progression of diabetic kidney disease may be less predictable than other forms of kidney failure, early referral for planning of renal and/or pancreas transplantation is paramount to optimize patient care and allow for possible preemptive transplantation.

Pancreas transplantation perceptions and practice: Results from a national US survey

BACKGROUND

Due to a substantial decline in pancreas transplantation (PT) across the United States over the past 15 years, we sought to understand the perceptions and practices of US PT programs.

METHODS

Surveys were sent to members of the American Society of Transplantation Surgeons and the American Society of Transplantation by email and professional society postings between August 2019 and November 2019.

RESULTS

One hundred twenty three responses were recorded from 56 unique programs. Program characteristics were obtained from the Scientific Registry of Transplant Recipients. Respondents were transplant surgeons (71%), transplant nephrologists (17%), trainees (9%), and allied professionals (3%). Programs were defined according to annual volume as: low (<5 PT/year), intermediate (6-20), or high (>20). High-volume programs reported that these factors were most important for increased PT: expansion of recipient selection, more aggressive donor utilization, and hiring of PT program-specific personnel. At both the program and national level, the vast majority (82% and 79%, respectively) felt the number of PTs currently performed are not in balance with patients' needs.

CONCLUSIONS

Overall, programs reported that the option of PT is not offered adequately to diabetic patients and that strategies to maintain higher PT volume are most evident at intermediate, and especially, high-volume programs.

Pancreas Transplantation for Patients with Type 1 and Type 2 Diabetes Mellitus in the United States: A Registry Report

Successful pancreas transplantation is still the only method to restore short-term and long-term insulin independence and good metabolic control for patients with diabetes. Since the first transplant in 1966, tremendous progress in outcome was made; however, transplant numbers have declined since 2004. This article describes the development and risk factors of pancreas transplantation with or without a kidney graft between 2001 and 2016. Patient survival and graft function improved significantly owing to careful recipient and donor selection, which reduced technical failure and immunologic graft loss rates.

Pancreas Transplantation: An Alarming Crisis in Confidence

In the past decade, the annual number of pancreas transplantations performed in the United States has steadily declined. From 2004 to 2011, the overall number of simultaneous pancreas-kidney (SPK) transplantations in the United States declined by 10%, whereas the decreases in pancreas after kidney (PAK) and pancreas transplant alone (PTA) procedures were 55% and 34%, respectively. Paradoxically, this has occurred in the setting of improvements in graft and patient survival outcomes and transplanting higher-risk patients. Only 11 centers in the United States currently perform ≥20 pancreas transplantations per year, and most centers perform <5 pancreas transplantations annually; many do not perform PAKs or PTAs. This national trend in decreasing numbers of pancreas transplantations is related to a number of factors including lack of a primary referral source, improvements in diabetes care and management, changing donor and recipient considerations, inadequate training opportunities, and increasing risk aversion because of regulatory scrutiny. A national initiative is needed to "reinvigorate" SPK and PAK procedures as preferred transplantation options for appropriately selected uremic patients taking insulin regardless of C-peptide levels or "type" of diabetes. Moreover, many patients may benefit from PTAs because all categories of pancreas transplantation are not only life enhancing but also life extending procedures.

β-cell replacement sources for type 1 diabetes: a focus on pancreatic ductal cells

Thorough research on the capacity of human islet transplantation to cure type 1 diabetes led to the achievement of 3- to 5-year-long insulin independence in nearly half of transplanted patients. Yet, translation of this technique to clinical routine is limited by organ shortage and the need for long-term immunosuppression, restricting its use to adults with unstable disease. The production of new bona fide β cells in vitro was thus investigated and finally achieved with human pluripotent stem cells (PSCs). Besides ethical concerns about the use of human embryos, studies are now evaluating the possibility of circumventing the spontaneous tumor formation associated with transplantation of PSCs. These issues fueled the search for cell candidates for β-cell engineering with safe profiles for clinical translation. In vivo studies revealed the regeneration capacity of the exocrine pancreas after injury that depends at least partially on facultative progenitors in the ductal compartment. These stimulated subpopulations of pancreatic ductal cells (PDCs) underwent β-cell transdifferentiation through reactivation of embryonic signaling pathways. In vitro models for expansion and differentiation of purified PDCs toward insulin-producing cells were described using cocktails of growth factors, extracellular-matrix proteins and transcription factor overexpression. In this review, we will describe the latest findings in pancreatic β-cell mass regeneration due to adult ductal progenitor cells. We will further describe recent advances in human PDC transdifferentiation to insulin-producing cells with potential for clinical translational studies.

Influence of donor-recipient sex mismatch on long-term survival of pancreatic grafts

To assess the role of sex mismatch on graft survival after pancreas transplantation. We evaluated 24,195 pancreas-transplant recipients reported in the Scientific Registry of Transplant Recipients over a 25-year period. Pancreatic graft survival (PGS) was analyzed according to donor–recipient sex pairing using Kaplan–Meier estimations. Hazard ratios were estimated using Cox proportional hazard models. A total of 14,187 male and 10,008 female recipients were included in final analyses. Mean follow-up was 8.3 ± 5.7 years. In multivariate analyses, neither recipient sex nor donor sex was associated with pancreatic graft failure (PGF), but donor–recipient sex mismatch (regardless of recipient sex) was an independent predictor of PGS (HR, 1.09; 95% CI, 1.04–1.14; p < 0.001). Compared with M → M sex-matched recipients in univariate analyses, M → F and F → M sex mismatches were associated with an increased risk of PGF. Adjustment for significant recipient and donor factors eliminated the association between F → M sex mismatch and PGF (HR, 1.02; 95% CI, 0.93–1.10; p = 0.752), but not M → F (1.09; 1.02–1.17; 0.020). Stratified analyses suggested that the negative effect of donor–recipient sex mismatch could be neutralized in older patients. These findings suggest that donor–recipient sex pairing should be taken into consideration in organ-allocation strategies.

New Insights into Diabetes Cell Therapy

Since insulin discovery, islet transplantation was the first protocol to show the possibility to cure patients with type 1 diabetes using low-risk procedures. The scarcity of pancreas donors triggered a burst of studies focused on the production of new β cells in vitro. These were rapidly dominated by pluripotent stem cells (PSCs) demonstrating diabetes-reversal potential in diabetic mice. Subsequent enthusiasm fostered a clinical trial with immunoisolated embryonic-derived pancreatic progenitors. Yet safety is the Achilles' heel of PSCs, and a whole branch of β cell engineering medicine focuses on transdifferentiation of adult pancreatic cells. New data showed the possibility to chemically stimulate acinar or α cells to undergo β cell neogenesis and provide opportunities to intervene in situ without the need for a transplant, at least after weighing benefits against systemic adverse effects. The current studies suggested the pancreas as a reservoir of facultative progenitors (e.g., in the duct lining) could be exploited ex vivo for expansion and β cell differentiation in timely fashion and without the hurdles of PSC use. Diabetes cell therapy is thus a growing field not only with great potential but also with many pitfalls to overcome for becoming fully envisioned as a competitor to the current treatment standards.

Beta-cell replacement therapy: current outcomes and future landscape

PURPOSE OF REVIEW

This article provides a summary of the current outcomes of β-cell replacement strategies, an algorithm for choosing a specific modality while highlighting associated advantages and disadvantages, and outlines remaining challenges and areas of active investigation in β-cell replacement therapy.

RECENT FINDINGS

The most recent reports of islet cell allotransplantation have shown improvements over previous eras and now rival some outcomes of pancreas alone transplantation. Active areas of investigation are focused on improving techniques for islet isolation, graft monitoring, and managing challenges posed by the innate and alloimmune systems.

SUMMARY

Patients with insulin-dependent diabetes who continue to experience life threatening hypoglycemia despite maximal medical management can benefit from β-cell replacement. Emerging nontransplant technologies have not provided a physiologic euglycemic state to the extent offered by transplantation. Islet transplantation eliminates hypoglycemic episodes/unawareness, facilitates normalization of hemoglobin A1c (HbA1c), decreases microvascular disease progression, and improves quality of life for patients with problematic diabetes. Mid- and long-term outcomes of islet transplantation performed at expert centers approximate those of registry reports of solitary pancreas transplant, whereas the complication profile is quite favorable.

Pancreas Transplantation of US and Non-US Cases from 2005 to 2014 as Reported to the United Network for Organ Sharing (UNOS) and the International Pancreas Transplant Registry (IPTR)

This report is an update of pancreas and kidney transplant activities in the US and non-US region in two periods, 2005-2009 and 2010-2014. The aim of the report was to analyze transplant progress and success in the US compared to non-US countries, and to compare trends between the two periods. Between 2005-2009 and 2010-2014, the number of US pancreas transplants declined by over 20%, while the overall number of pancreas transplants performed outside the US has increased. The decline in US numbers is predominantly due to the decline in primary and secondary pancreas after kidney transplants (PAK). During the time period studied, the number of PAK transplants dropped by 50%. In contrast, the number of simultaneous pancreas/kidney transplants (SPK) declined by only 10%, and the number of pancreas transplants alone (PTA) by 20%. Over 90% of pancreas transplants worldwide were performed, with a simultaneous kidney transplant and excellent results. Transplant outcomes in SPK improved significantly because of a decrease in the rates of technical and immunologic graft loss. In 2010-2014 vs. 2005-2009, US SPK transplant patient survival at 1 year post-transplant increased from 95.7% to 97.4%, pancreas graft function from 88.3% to 91.3%, and kidney function from 93.6% to 95.5%. A significant improvement was also noted in PAK transplants. One-year patient survival increased from 96.4% to 97.9% and pancreas graft function from 81.0% to 86.0%. PTA 1-year patient survival remained constant at 97%, and pancreas 1-year graft survival improved from 81.0% to 85.7%. With the decline in the number of transplants, a change towards better pancreas donor selection was observed. In solitary transplants, the donors were primarily young trauma victims, and the pancreas preservation time was relatively short. A general tendency towards transplanting older recipients was noted. In 2010-2014 vs. 2005-2009, PTA recipients 50 years of age or older accounted for 32% vs. 22%, PAK for 28% vs. 22%, and SPK for 22% vs. 20%. This may be due to a relatively lower immunologic graft loss rate, especially in solitary transplants, which historically has been high in young recipients. The number of pancreas transplants in patients with type 2 diabetes and end-stage renal disease has increased, and accounted for 9% of all SPK recipients in 2010-2014.