Long-term outcome after pancreas transplantation: a registry analysis. Curr Opin Organ Transplant. 2016;21:377-385. [PMID: 27258580 DOI: 10.1097/mot.0000000000000331]

Evolving Trends in the Management of Duodenal Leaks After Pancreas Transplantation: A Single-Centre Experience

Duodenal leaks (DL) contribute to most graft losses following pancreas transplantation. However, there is a paucity of literature comparing graft preservation approach versus upfront graft pancreatectomy in these patients. We reviewed all pancreas transplants performed in our institution between 2000 and 2020 and identified the recipients developing DL to compare based on their management: percutaneous drainage vs. operative graft preservation vs. upfront pancreatectomy. Of the 595 patients undergoing pancreas transplantation, 74 (12.4%) developed a duodenal leak with a median follow up of 108 months. Forty-five (61%) were managed by graft preservation strategies, with the rest being treated with upfront graft pancreatectomy. DL managed by graft preservation strategies had similar graft survival rates at 1 and 5-year compared to the matched cohort of population without DL (95% and 59% vs. 91% and 62%; p = 0.78). Multivariate analysis identified male recipient (OR: OR: 6.18; CI95%: 1.26-41.09; p = 0.04) to have higher odds of undergoing an upfront graft pancreatectomy. In appropriately selected recipients with DL, graft preservation strategies utilizing either interventional radiology guided percutaneous drainage or laparotomy with/without repair of leak can achieve comparable long-term graft survival rates compared to recipients without DL.

Management of Failing Kidney and Pancreas Transplantations

Survival rates for allografts have improved over the last 2 decades, yet failing allografts remains a challenge in the field of transplant. The risks of mortality and morbidity associated with failed allografts are compounded by infectious complications and metabolic abnormalities, emphasizing the need for a standardized approach to management. Management of failing allografts lacks consensus, highlighting the need for unified protocols to guide treatment protocols and minimize risks with postdialysis initiation. The decision to wean off immunosuppression depends on various factors, including living donor availability and infectious risks, necessitating improved coordination of care and a standard guideline. Treatment of failed pancreas focuses on glycemic control, with insulin as the mainstay, while considering surgical interventions such as graft pancreatectomy in advanced symptomatic cases. Navigating the complexities of failed allograft management demands a multidisciplinary approach and standardized stepwise protocol. Addressing the gaps in management plans for failing allografts and employing a systematic approach to transplant decisions will enhance patient outcomes and facilitate informed decision-making.

Accessibility of Percutaneous Biopsy in Retrocolic-Placed Pancreatic Grafts With a Duodeno-Duodenostomy

Duodeno-duodenostomy (DD) has been proposed as a more physiological alternative to conventional duodeno-jejunostomy (DJ) for pancreas transplantation. Accessibility of percutaneous biopsies in these grafts has not yet been assessed. We conducted a retrospective study including all pancreatic percutaneous graft biopsies requested between November 2009 and July 2021. Whenever possible, biopsies were performed under ultrasound (US) guidance or computed tomography (CT) guidance when the US approach failed. Patients were classified into two groups according to surgical technique (DJ and DD). Accessibility, success for histological diagnosis and complications were compared. Biopsy was performed in 93/136 (68.4%) patients in the DJ group and 116/132 (87.9%) of the DD group (p = 0.0001). The graft was not accessible for biopsy mainly due to intestinal loop interposition (n = 29 DJ, n = 10 DD). Adequate sample for histological diagnosis was obtained in 86/93 (92.5%) of the DJ group and 102/116 (87.9%) of the DD group (p = 0.2777). One minor complication was noted in the DD group. The retrocolic position of the DD pancreatic graft does not limit access to percutaneous biopsy. This is a safe technique with a high histological diagnostic success rate.

Generating strategies for a national comeback in pancreas transplantation: A Delphi survey and US conference report

In the United States, potential transplant candidates with insulin-dependent diabetes mellitus are inconsistently offered pancreas transplantation (PTx), contributing to a dramatic decline in pancreas allograft utilization over the past 2 decades. The American Society of Transplantation organized a workshop to identify barriers inhibiting PTx and to develop strategies for a national comeback. The 2-day workshop focused on 4 main topics: (1) referral/candidate selection, (2) organ recovery/utilization, (3) program performance/patient outcomes, and (4) enhanced education/research. Topics were explored through expert presentations, patient testimonials, breakout sessions, and strategic planning, including the identification of tasks for immediate focus. Additionally, a modified-Delphi survey was conducted among workshop members to develop and rate the importance of barriers, and the impact and feasibility of workgroup-identified improvement strategies. The panelists identified 16 barriers to progress and 44 strategies for consideration. The steps for a national comeback in PTx involve greater emphasis on efficient referral and candidate selection, better donor pancreas utilization practices, eliminating financial barriers to procurement and transplant, improving collaboration between transplant and diabetes societies and professionals, and increasing focus on PTx training, education, and research. Partnership between national societies, patient advocacy groups, and professionals will be essential to realizing this critical agenda.

Pancreas after kidney transplantation, is it the time to overcome the stigma?

BACKGROUND

Pancreas transplantation is the most effective treatment to improve quality of life and overcome complications in patients with end-stage renal disease and diabetes mellitus. One of the main approaches for concurrent renal disease and diabetes mellitus which has been underutilized during the past decade is a pancreas transplant after kidney transplantation. Our study aimed to quantify outcomes following pancreas after kidney transplants (PAKs) in the United States from 2001 to 2020 with an emphasis on graft and patient survival.

METHODS AND MATERIALS

A retrospective registry analysis was performed by accessing the OPTN/UNOS database for PAKs that were performed in the United States from January 2001 to April 2020. The study population was divided into two subgroups: patients receiving a pancreas transplant between 2001 and 2010 and those receiving a pancreas transplant between 2011 and 2020.

RESULTS

The study examined a total number of 3706 PAK recipients; patients who received a PAK from January 2001 through December 2010 (n = 2892) and those who received a PAK from January 2011 to April 2020 (n = 814). The selection process of transplant recipients did not drastically change throughout the 2001-2010 and 2011-2020 periods. Length of stay at the hospital after the transplantation improved significantly in the 2011-2020 group relative to the 2001-2010 group (8.48 vs. 10.08 days, mean, p < 0.01). Additionally, more transplantation with 4-6 human leukocyte antigen mismatch occurred in the 2011-2020 group than in the 2001-2010 group (80.6% vs. 71.4%, p < 0.01). The pancreas preservation time of 13.35 h in the 2001-2010 group decreased significantly to 11.17 h in the 2011-2020 group (p < 0.001). The mean donor's amylase and lipase also decreased significantly in the 2011-2020 cohort. Significant graft survival improvement was observed in the 2011-2020 group compared to the 2001-2010 group after a long-term follow-up (p < 0.001). The mean Calculated Pancreas Donor Risk Index was 1.08 for the 2001-2010 group and 0.99 for the 2011-2020 group with a significant difference (p < 0.001).

CONCLUSION

The beneficial results and improved outcomes observed in PAK patients demonstrate the effectiveness of the operation for individuals in need of a pancreas transplant. PAKs can prove to be a meaningful solution to overcome long waiting times, decrease the donor-recipient imbalance, expand the donor pool, and overcome the current underutilization in order to improve the short- and long-term quality of life in the groups of interest.

From stem cells to pancreatic β-cells: strategies, applications, and potential treatments for diabetes

Loss and functional failure of pancreatic β-cells results in disruption of glucose homeostasis and progression of diabetes. Although whole pancreas or pancreatic islet transplantation serves as a promising approach for β-cell replenishment and diabetes therapy, the severe scarcity of donor islets makes it unattainable for most diabetic patients. Stem cells, particularly induced pluripotent stem cells (iPSCs), are promising for the treatment of diabetes owing to their self-renewal capacity and ability to differentiate into functional β-cells. In this review, we first introduce the development of functional β-cells and their heterogeneity and then turn to highlight recent advances in the generation of β-cells from stem cells and their potential applications in disease modeling, drug discovery and clinical therapy. Finally, we have discussed the current challenges in developing stem cell-based therapeutic strategies for improving the treatment of diabetes. Although some significant technical hurdles remain, stem cells offer great hope for patients with diabetes and will certainly transform future clinical practice.

Impact of pancreas transplantation alone on kidney function: A multicenter clinical cohort study

Pancreas transplantation alone (PTA) is a β cell replacement option for selected patients with type 1 diabetes mellitus; concerns have been raised regarding deterioration in kidney function (KF) after PTA. This retrospective multicenter study assessed actual impact of transplantation and immunosuppression on KF in PTA recipients at three Transplant Centers. The primary composite endpoint 10 years after PTA was >50% eGFR decline, eGFR < 30 mL/min/1.73 m2 , and/or receiving a kidney transplant (KT). Overall, 822 PTA recipients met eligibility. Median baseline and 10-year eGFR (mL/min/1.73 m2 ) were 76.3 (58.1-100.8) and 51.3 (35.3-65.9), respectively. Primary composite endpoint occurred in 98 patients (53.5%) with 45 experiencing a >50% decrease in eGFR by 10 years post-transplant, 38 eGFR < 30 mL/min/1.73 m2 and 49 requiring KT. KF declined most significantly within 6 months post-PTA, more often in females and patients with better preserved GFR up to 5 years with 11.6% kidney failure at 10 years. Patient survival and death-censored graft survival were both 68% at 10 years with overall graft thrombosis rate 8%. KF declined initially after PTA but stabilized with further slow progression. In conclusion, prospective intervention studies are needed to test renal sparing interventions while gathering more granular data.

Medical and Surgical Management of the Failed Pancreas Transplant

Despite the continued improvements in pancreas transplant outcomes in recent decades, a subset of recipients experience graft failure and can experience substantial morbidity and mortality. Here, we summarize what is known about the failed pancreas allograft and what factors are important for consideration of retransplantation. The current definition of pancreas allograft failure and its challenges for the transplant community are explored. The impacts of a failed pancreas allograft are presented, including patient survival and resultant morbidities. The signs, symptoms, and medical and surgical management of a failed pancreas allograft are described, whereas the options and consequences of immunosuppression withdrawal are reviewed. Medical and surgical factors necessary for successful retransplant candidacy are detailed with emphasis on how well-selected patients may achieve excellent retransplant outcomes. To achieve substantial medical mitigation and even pancreas retransplantation, patients with a failed pancreas allograft warrant special attention to their residual renal, cardiovascular, and pulmonary function. Future studies of the failed pancreas allograft will require improved reporting of graft failure from transplant centers and continued investigation from experienced centers.

Surgical complications after pancreatic transplantation: A computed tomography imaging pictorial review

Pancreatic transplantation is considered by the American Diabetes Association and the European Association for the Study of Diabetes an acceptable surgical procedure in patients with type 1 diabetes also undergoing kidney transplantation in pre-final or end-stage renal disease if no contraindications are present. Pancreatic transplantation, however, is a complex surgical procedure and may lead to a range of postoperative complications that can significantly impact graft function and patient outcomes. Postoperative computed tomography (CT) is often adopted to evaluate perfusion of the transplanted pancreas, identify complications and as a guide for interventional radiology procedures. CT assessment after pancreatic transplantation should start with the evaluation of the arterial Y-graft, the venous anastomosis and the duodenojejunostomy. With regard to complications, CT allows for the identification of vascular complications, such as thrombosis or stenosis of blood vessels supplying the graft, the detection of pancreatic fluid collections, including pseudocysts, abscesses, or leaks, the assessment of bowel complications (anastomotic leaks, ileus or obstruction), and the identification of bleeding. The aim of this pictorial review is to illustrate CT findings of surgical-related complications after pancreatic transplantation. The knowledge of surgical techniques is of key importance to understand postoperative anatomic changes and imaging evaluation. Therefore, we first provide a short summary of the main techniques of pancreatic transplantation. Then, we provide a practical imaging approach to pancreatic transplantation and its complications providing tips and tricks for the prompt imaging diagnosis on CT.

Ultrasound of pancreatic transplant complications: a primer for radiologists

Pancreatic transplantation is an established treatment for patients with type 1 diabetes patients and select type 2 diabetes patients, with excellent survival rates as graft health is evaluated through regular imaging and early detection of complications. Amongst the various imaging methods that may aid in diagnosis of pancreatic transplant complications, ultrasound is a widely available, quick, portable, and cost-effective technique, often used as the sole method to assess for pancreatic transplant complications. When assessing a patient with a pancreatic transplant, the radiologist should be methodical in assessing the vasculature, the pancreatic parenchyma, and the peripancreatic regions. Complications can be categorised based on time from transplant and type of complications, and include vascular, parenchymal, and enteric/anastomotic complications. Doppler has a major role in the diagnosis of vascular complications including arterial and venous thrombosis, arterial stenosis, pseudoaneurysms, and haematomas. Pancreatic complications include rejections and pancreatitis, and are often diagnosed through a combination of clinical, laboratory, and imaging findings, such as pancreatic heterogeneity or the presence of pancreatic pseudocysts. Enteric/anastomotic complications include leaks and bowel obstructions, and may require cross-sectional imaging in addition to ultrasound. This review covers the most common and high-impact vascular, parenchymal, and enteric/anastomotic complications that should be considered in every radiologist's search pattern when assessing a pancreatic graft, as well as their respective postoperative timeframes.

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.

Pancreatic Allograft Thrombosis: Implementation of the CPAT-Grading System in a Retrospective Series of Simultaneous Pancreas-Kidney Transplantation

Pancreatic graft thrombosis (PAT) is a major surgical complication, potentially leading to graft loss. The recently proposed Cambridge Pancreas Allograft Thrombosis (CPAT) grading system provides diagnostic, prognostic and therapeutic recommendations. The aim of the present study was to retrospectively assess computed tomography angiography (CTA) examinations performed routinely in simultaneous pancreas-kidney (SPK) recipients to implement the CPAT grading system and to study its association with the recipients' outcomes. We retrospectively studied 319 SPK transplant recipients, who underwent a routine CTA within the first 7 postoperative days. Analysis of the CTA scans revealed PAT in 215 patients (106 grade 1, 85 grade 2, 24 grade 3), while 104 showed no signs. Demographic data of the patients with and without PAT (thrombosis and non-thrombosis group) were not significantly different, except for the higher number of male donors in the thrombosis group. Pancreatic graft survival was significantly shorter in the thrombosis group. Graft loss due to PAT was significantly associated with grade 2 and 3 thrombosis, while it did not differ for recipients with grade 0 or grade 1 thrombosis. In conclusion, the CPAT grading system was successfully implemented in a large series of SPK transplant recipients and proved applicable in clinical practice.

Comparison of Outcomes and Survival of Two Cohorts of Patients with Simultaneous Pancreas-Kidney Transplantation: A Retrospective Cohort Study in a Latin American Hospital

Background

Simultaneous pancreas-kidney transplantation (SPKT) is a complex and demanding procedure with a considerable risk of morbidity and mortality. Advances in surgical techniques and organ preservation have introduced changes in care protocols. Two cohorts of patients receiving SPKT with two different protocols were compared to determine overall survival and pancreatic and renal graft failure-free survival.

Methods

This retrospective observational study was conducted in two cohorts of SPKT recipient patients that underwent surgery between 2001 and 2021. Outcomes were compared in transplant patients between 2001 and 2011 (cohort 1; initial protocol) and 2012-2021 (cohort 2; improved protocol). In addition to the temporality, the cohorts were defined by a protocolization of technical aspects and medical management in cohort 2 (improved protocol), compared to a wide variability in the procedures carried out in cohort 1 (initial protocol). Overall survival and pancreatic and renal graft failure-free survival were the primary outcomes. These outcomes were determined using Kaplan-Meier survival analysis and the log-rank test.

Results

Fifty-five SPKT were performed during the study period: 32 in cohort 1 and 23 in cohort 2. In the survival analysis, an average of 2546 days (95% CI: 1902-3190) was found in cohort 1, while in cohort 2, it was 2540 days (95% CI: 2100-3204) (p > 0.05). Pancreatic graft failure-free survival had an average of 1705 days (95% CI: 1037-2373) in cohort 1, lower than the average in cohort 2 (2337 days; 95% CI: 1887-2788) (p = 0.016). Similarly, renal graft failure-free survival had an average of 2167 days (95% CI: 1485-2849) in cohort 1, lower than the average in cohort 2 (2583 days; 95% CI: 2159-3006) (p = 0.017).

Conclusions

This analysis indicates that pancreatic and renal graft failure-free survival associated with SPKT decreased significantly in cohort 2, with results related to improvements in the treatment protocol implemented in that cohort.

Revitalizing pancreas transplantation: creation of a hands-on training course for pancreas allograft procurement, backbench preparation, and transplantation

Despite a steady increase in the number of organs available for transplant in the United States, over the last two decades there has been a precipitous decrease in the annual number of pancreas transplants performed. One overlooked consequence of this decline in pancreas transplant volume has been a decrease in experience in proper pancreas procurement and transplantation techniques for transplant surgeons as well as fewer trained abdominal transplant fellows entering the workforce certified for pancreas procurement and transplantation, with those achieving certification having less-developed judgment, skills, and experience. To augment current fellowship training and provide a concentrated experience in pancreas procurement and transplantation, the ASTS developed a hands-on surgical skills workshop focused on proper techniques for pancreas allograft procurement and backbench preparation.

Pancreas and Islet Transplantation: Comparative Outcome Analysis of a Single-centre Cohort Over 20-years

OBJECTIVE

To provide the largest single-center analysis of islet (ITx) and pancreas (PTx) transplantation.

SUMMARY BACKGROUND DATA

Studies describing long-term outcomes with ITx and PTx are scarce.

METHODS

We included adults undergoing ITx (n=266) and PTx (n=146) at the University of Alberta from January 1999 to October 2019. Outcomes include patient and graft survival, insulin independence, glycemic control, procedure-related complications, and hospital readmissions. Data are presented as medians (interquartile ranges, IQR) and absolute numbers (percentages, %) and compared using Mann-Whitney and χ2 tests. Kaplan-Meier estimates, Cox proportional hazard models and mixed main effects models were implemented.

RESULTS

Crude mortality was 9.4% and 14.4% after ITx and PTx, respectively ( P= 0.141). Sex-adjusted and age-adjusted hazard-ratio for mortality was 2.08 (95% CI, 1.04-4.17, P= 0.038) for PTx versus ITx. Insulin independence occurred in 78.6% and 92.5% in ITx and PTx recipients, respectively ( P= 0.0003), while the total duration of insulin independence was 2.1 (IQR 0.8-4.6) and 6.7 (IQR 2.9-12.4) year for ITx and PTx, respectively ( P= 2.2×10 -22 ). Graft failure ensued in 34.2% and 19.9% after ITx and PTx, respectively ( P =0.002). Glycemic control improved for up to 20-years post-transplant, particularly for PTx recipients (group, P= 7.4×10 -7 , time, P =4.8×10 -6 , group*time, P= 1.2×10 -7 ). Procedure-related complications and hospital readmissions were higher after PTx ( P =2.5×10 -32 and P= 6.4×10 -112 , respectively).

CONCLUSIONS

PTx shows higher sex-adjusted and age-adjusted mortality, procedure-related complications and readmissions compared with ITx. Conversely, insulin independence, graft survival and glycemic control are better with PTx. This study provides data to balance risks and benefits with ITx and PTx, which could improve shared decision-making.

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&lt;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&lt;0.05) while SPK recipients showed higher absolute cytokine concentrations (TNF, IL-1ra, IL-8, MIP-1α, and IL-4; all p&lt;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

Sterile Pancreas Inflammation during Preservation and after Transplantation

The pancreas is very susceptible to ischemia-reperfusion injury. Early graft losses due to pancreatitis and thrombosis represent a major issue after pancreas transplantation. Sterile inflammation during organ procurement (during brain death and ischemia-reperfusion) and after transplantation affects organ outcomes. Sterile inflammation of the pancreas linked to ischemia-reperfusion injury involves the activation of innate immune cell subsets such as macrophages and neutrophils, following tissue damage and release of damage-associated molecular patterns and pro-inflammatory cytokines. Macrophages and neutrophils favor tissue invasion by other immune cells, have deleterious effects or functions, and promote tissue fibrosis. However, some innate cell subsets may promote tissue repair. This outburst of sterile inflammation promotes adaptive immunity activation via antigen exposure and activation of antigen-presenting cells. Better controlling sterile inflammation during pancreas preservation and after transplantation is of utmost interest in order to decrease early allograft loss (in particular thrombosis) and increase long-term allograft survival. In this regard, perfusion techniques that are currently being implemented represent a promising tool to decrease global inflammation and modulate the immune response.

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.

Challenges with Cell-based Therapies for Type 1 Diabetes Mellitus

Type 1 diabetes (T1D) is a chronic, lifelong metabolic disease. It is characterised by the autoimmune-mediated loss of insulin-producing pancreatic β cells in the islets of Langerhans (β-islets), resulting in disrupted glucose homeostasis. Administration of exogenous insulin is the most common management method for T1D, but this requires lifelong reliance on insulin injections and invasive blood glucose monitoring. Replacement therapies with beta cells are being developed as an advanced curative treatment for T1D. Unfortunately, this approach is limited by the lack of donated pancreatic tissue, the difficulties in beta cell isolation and viability maintenance, the longevity of the transplanted cells in vivo, and consequently high costs. Emerging approaches to address these limitations are under intensive investigations, including the production of insulin-producing beta cells from various stem cells, and the development of bioengineered devices including nanotechnologies for improving islet transplantation efficacy without the need for recipients taking toxic anti-rejection drugs. These emerging approaches present promising prospects, while the challenges with the new techniques need to be tackled for ultimately clinical treatment of T1D. This review discussed the benefits and limitations of the cell-based therapies for beta cell replacement as potential curative treatment for T1D, and the applications of bioengineered devices including nanotechnology to overcome the challenges associated with beta cell transplantation.

Different timing and risk factors of cause-specific pancreas graft loss after simultaneous pancreas kidney transplantation

In cases after pancreas transplantation (PTx), the pancreas graft might be lost for various reasons, including a pancreatoduodenal graft-related complication or patient death with a functioning graft. Although the causes seem to have distinct characteristics, the causes of pancreas graft loss have not been characterized. This study aimed to characterize the causes of pancreas graft loss by analyzing data from a Japanese nationwide registry. This study included 391 patients who received simultaneous pancreas-kidney transplantation among 461 patients with PTx during the study period in approved institutions in Japan. We characterized each cause in terms of the timing of the cause-specific graft loss and preoperative factors associated with graft loss based on nationwide data from a Japanese nationwide registry. Among the 391 cases, 113 lost the pancreas graft due to patient death with a functioning graft (DWFG; n = 34, 44.2%), graft thrombus (n = 22, 28.6%), or chronic rejection (CR; n = 7, 9.1%). Average (± standard deviation) time from PTx to graft loss due to DWFG, graft thrombus, and CR was 3.70 ± 4.36, 0.02 ± 0.01, and 2.37 ± 2.08 years, respectively. Duration of type 1 diabetes mellitus and donor body mass index were significantly associated with pancreas graft loss due to DWFG and graft thrombus, respectively. This characterization showed that the timing and preoperative factors associated with pancreas graft loss were significantly different for different causes of graft loss. These results may inform PTx follow-up protocols to ensure that appropriate care is based on the cause of graft loss.

Pancreas Transplantation in Minorities including Patients with a Type 2 Diabetes Phenotype

Background: Prior to year 2000, the majority of pancreas transplants (PTx) were performed as simultaneous pancreas-kidney transplants (SPKTs) in Caucasian adults with end stage renal failure secondary to type 1 diabetes mellitus (T1DM) who were middle-aged. In the new millennium, improving outcomes have led to expanded recipient selection that includes patients with a type 2 diabetes mellitus (T2DM) phenotype, which excessively affects minority populations. Methods: Using PubMed® to identify appropriate citations, we performed a literature review of PTx in minorities and in patients with a T2DM phenotype. Results: Mid-term outcomes with SPKT in patients with uremia and circulating C-peptide levels (T2DMphenotype) are comparable to those patients with T1DM although there may exist a selection bias in the former group. Excellent outcomes with SPKT suggests that the pathophysiology of T2DM is heterogeneous with elements consisting of both insulin deficiency and resistance related to beta-cell failure. As a result, increasing endogenous insulin (Cp) production following PTx may lead to freedom checking blood sugars or taking insulin, better metabolic counter-regulation, and improvements in quality of life and life expectancy compared to other available treatment options. Experience with solitary PTx for T2DM or in minorities is limited but largely mirrors the trends reported in SPKT. Conclusions: PTx is a viable treatment option in patients with pancreas endocrine failure who are selected appropriately regardless of diabetes type or recipient race. This review will summarize data that unconventional patient populations with insulin-requiring diabetes may gain value from PTx with an emphasis on contemporary experiences and appropriate selection in minorities in the new millennium.

Lasting Over Time: 20-Year Follow-Up of Living Related Simultaneous Pancreas-Kidney Transplant Between Identical Twins

BACKGROUND

Twenty-year follow-up of the first reported simultaneous pancreas-kidney transplant from living donor between identical twins.

CASE

We present a case of a patient after the world's first simultaneous pancreas and kidney transplant between identical twins. The transplant was performed because of diabetes mellitus type (DM1) related renal failure. Now in her sixties, the patient has had exceptional prolonged bi-graft function without immunosuppression. She is free from DM1 recurrence, does not take insulin, and her creatinine level has stayed with the normal limit.

CONCLUSIONS

Simultaneous pancreas and kidney transplant can be performed successfully with excellent long-term outcomes.

Benefits and Hurdles of Pancreatic β-Cell Replacement

Insulin represents a life-saving treatment in patients with type 1 diabetes, and technological advancements have improved glucose control in an increasing number of patients. Despite this, adequate control is often still difficult to achieve and insulin remains a therapy and not a cure for the disease. β-cell replacement strategies can potentially restore pancreas endocrine function and aim to maintain normoglycemia; both pancreas and islet transplantation have greatly progressed over the last decades and, in subjects with extreme glycemic variability and diabetes complications, represent a concrete and effective treatment option. Some issues still limit the adoption of this approach on a larger scale. One is represented by the strict selection criteria for the recipient who can benefit from a transplant and maintain the lifelong immunosuppression necessary to avoid organ rejection. Second, with regard to islet transplantation, up to 40% of islets can be lost during hepatic engraftment. Recent studies showed very preliminarily but promising results to overcome these hurdles: the ability to induce β-cell maturation from stem cells may represent a solution to the organ shortage, and the creation of semi-permeable membranes that envelope or package cells in either micro- or macro- encapsulation strategies, together with engineering cells to be hypo-immunogenic, pave the way for developing strategies without immunosuppression. The aim of this review is to describe the state of the art in β-cell replacement with a focus on its efficacy and clinical benefits, on the actual limitations and still unmet needs, and on the latest findings and future directions.

Validating the US pancreas donor risk index in a Norwegian population, a retrospective observational study

OBJECTIVES

Despite advances in immunosuppression and surgical technique, pancreas transplantation is still associated with a significant graft loss rate. The Pancreas Donor Risk Index (PDRI) is a pre-transplant scoring tool derived from a US population. We sought to validate the PDRI in a Norwegian population.

METHODS

We retrospectively retrieved donor data for 344 pancreas transplants undertaken in Norway between 2000 and 2019, utilising the Scandiatransplant database, and matched these to the respective recipients. The PDRI score was calculated for each transplanted pancreas, these were then stratified into quintiles. The association between the PDRI quintiles and 1-year graft survival was calculated, and this was repeated for the different types of pancreas transplantation. The association between PDRI as a continuous variable, and graft survival was determined. Donor and recipient data were compared to the original US population.

RESULTS

The overall 1-year graft survival was 82.7%. There were no significant differences in survival between the different PDRI quintiles. When viewed as a continuous variable, increased PDRI score was not associated with decreased graft survival. Significant differences between the Norwegian and US populations were found.

CONCLUSIONS

When applied to a Norwegian population, the PDRI score was unable to predict 1-year graft survival.

Secretome effect of adipose tissue-derived stem cells cultured two-dimensionally and three-dimensionally in mice with streptozocin induced type 1 diabetes

Aims

To analyze therapeutic potential of the conditioned medium from adipose tissue-derived stem cells (ASC) cultivated in 2D (CM-2D) and 3D (CM-3D) models, in mice with Type 1 diabetes (T1D) induced by streptozotocin.

Main methods

Viability andCD105 expression of 2D and 3D ASC were analyzed by flow cytometry. T1D was induced in mice by multiple injections of streptozocin. On the 28th and 29th days after the first injection of streptozocin, diabetic animals received CM-2D or CM-3D. Pancreatic, CM-2D, and CM-3D cytokines were analyzed by cytometric bead array (CBA) and insulin and PDX-1 were observed and quantified by immunohistochemistry. Apoptosis-related proteins were quantified by Western Blotting.

Key findings

ASC in three-dimensional culture released increased levels of IL-6 and IL-2, while IL-4 was decreased. CM-2D induced pancreatic PDX-1 expression and was able to reduce glycemia in diabetic mice one week after injections but not CM-3D. On the other hand, CM-2D and CM-3D were not able to reverse apoptosis of pancreatic cells in diabetic mice nor to increase insulin expression.

Significance

Together, these results demonstrate that the 3D cell culture secretome was not able to improve diabetes type 1 symptoms at the times observed, while 2D cell secretome improved glycemic levels in T1D mice.

Race does not predict pancreas graft failure after pancreas transplantation in the Modern Era

BACKGROUND

African-American (AA) has historically been associated with inferior graft survival after pancreas transplantation. However, with the improvement of immunosuppression and surgical technique, we hypothesized that the racial disparity has been neutralized.

METHODS

We analyzed data from the Scientific Registry of Transplant Recipients (1989-2018). Using Kaplan-Meier estimation and Cox proportional hazards regression, we examined the influence of race on pancreatic graft survival.

RESULTS

Before 2009, AA recipients had a higher risk of pancreatic graft failure after adjusting for confounding factors (hazard ratio [HR]: 1.16, 95% confidence interval [CI]: 1.08-1.24), but the risks for Hispanic and Asian recipients were both comparable to their Caucasian counterparts. However, the risk of pancreatic graft failure in AA recipients dropped to 1% and was no longer significant since 2009 (HR: 1.01, 95%CI: 0.88-1.16). Interestingly, donor race showed similar results. Furthermore, the concordance statistic of the complete pancreas donor risk index (including donor race) was 0.582, whereas the concordance did not change when donor race was eliminated from the model.

CONCLUSIONS

AA and other races have shown similar pancreatic graft survival in the modern era. Furthermore, donor racial disparity also seems neutralized; thus, donor race should not be considered as an indicator of pancreatic donor quality. This article is protected by copyright. All rights reserved.

Weight gain following pancreas transplantation in type 1 diabetes is associated with a worse glycemic profile: A retrospective cohort study

AIMS

Evaluate the weight trajectories after pancreas transplantation (PT) and their relationships with pancreas graft outcomes in type 1 diabetes (T1D).

METHODS

Retrospective cohort study. T1D individuals who underwent PT were recruited (T1D-PT; n = 194) and divided into three groups according to transplantation date: 1999-2004 (n = 57), 2005-2009 (n = 79), 2010-2015 (n = 58). For weight comparisons, a random sample of T1D without renal impairment was also recruited during 2015 (n = 61; T1D-control).

RESULTS

The median follow-up for the T1D-PT group was 11.1 years. Despite significant weight loss at 6 months (65.7 ± 12.4 vs. 64.1 ± 11.4 Kg; p < 0.001), a stepped increase was seen thereafter (60 months: 68.0 ± 14.0 Kg; p < 0.001). Participants from the 2010-2015 period showed higher weight gain (p < 0.001), outweighing that observed in the T1D-control (60 months: +4.69 ± 8.49 vs. -0.97 ± 4.59 Kg; p = 0.003). Weight gain between 6 and 36 months was directly associated with fasting glucose and HbA1c at 36 months, and with HbA1c at 60 months (p < 0.05). However, in Cox-regression models adjusted for age, sex, and several recipient and PT-related variables, the third tertile of weight gain between 6 and 36 months showed a non-significant increase in the graft failure/dysfunction (HR 2.33 [0.75-7.27]).

CONCLUSIONS

Weight gain post-PT was associated with glucose-related biochemical markers of graft dysfunction, which needs confirmation in further studies.

Donor Predictors of Donor Pancreas Retrieval and Subsequent Solid Pancreas Transplantation in Australia and New Zealand from 2007 to 2016

BACKGROUND

Donor characteristics help guide donor pancreas acceptance for solid pancreas-kidney transplantation; however, these criteria vary worldwide. Such variation could result in nonuse of potentially transplantable organs. Using a registry cohort, we identified donor characteristics associated with donor pancreas retrieval and subsequent solid pancreas transplantation in Australia and New Zealand.

METHODS

Australia and New Zealand Organ Donor registry donor data from 2007 to 2016 were used to define cohort 1 (all donors authorized for pancreas retrieval) and cohort 2 (all retrieved donor pancreata considered for solid pancreas transplantation). Donor factors significantly associated with donor pancreas retrieval (cohort 1) and solid pancreas transplantation of retrieved donor pancreata (cohort 2) were determined via multivariable logistic regression.

RESULTS

Nonretrieval and nonuse of solid organ donor pancreas increased throughout the study period, and nonauthorization for pancreas donation remained stable. Donor body mass index, sex, and viral serology were associated with donor pancreas retrieval but not transplantation. Donor age, cause of death, donation after brain death status, terminal serum creatinine, and donor region were associated with both donor pancreas retrieval and acceptance for solid pancreas transplantation with donation after brain death status being the strongest predictor for both outcomes.

CONCLUSIONS

Donor age, cause of death, donation after brain death status, terminal serum creatinine, and donor region were associated with both donor pancreas retrieval and subsequent transplantation in Australia and New Zealand. Subsequent correlation of these factors with post-pancreas transplant outcomes would help guide pancreas transplant decisions and minimize nonuse of potentially usable donor pancreata.

Survival benefit of the homologous kidney allograft in simultaneous pancreas-kidney transplants and its potential protective role

The superior death-censored graft survival of the pancreas allograft in simultaneous pancreas kidney transplants (SPK) over pancreas alone transplants (PTA) has long been recognized. Using data from the Scientific Registry of Transplant Recipients (SRTR) and a high-volume pancreas transplant program, we investigated the possible protective role of the kidney allograft in SPK transplants. We analyzed 19,043 primary pancreas transplants between 2000 and 2020, including 735 transplants performed at the University of Minnesota. SPK transplants demonstrated a superior death-censored graft survival over pancreas after kidney (PAK) and simultaneous pancreas and living donor kidney (SPLK) transplants, which both demonstrated better survival than PTA transplants. This effect was not affected by mode or duration of renal replacement therapy prior to transplant. Furthermore, we found that HLA match at the B-locus between the prior kidney and current pancreas allografts demonstrated a protective effect (HR 0.54; 95% confidence interval 0.29-1.00), with a 2-antigen match demonstrating superior death-censored graft survival to a 1- or 0-antigen match. We propose that a homologous kidney allograft in SPK transplants affords protection to the pancreas allograft - likely through a combination of better surveillance for rejection and direct immunoprotection offered by the same-donor kidney. This article is protected by copyright. All rights reserved.

Solid pancreas transplant outcomes with increased donor and recipient ages compared to reference ages: A systematic review

BACKGROUND

Increased recipient and donor age are associated with worse solid organ pancreas transplant outcomes. However, donor and recipient age criteria vary between jurisdictions. We systematically reviewed studies reporting the association between transplanting older recipients and donors beyond current Transplantation Society of Australia and New Zealand (TSANZ) limits with solid pancreas transplant outcomes.

METHODS

Studies comparing transplant outcomes between a reference-age and an older-age donor (>45 years) or recipient (≥50 years) cohort for solid pancreas transplantation were included. Primary outcomes were pancreas/kidney graft and patient survival at one and five years. Secondary outcomes were post-transplant complications (graft thrombosis, acute rejection and relaparotomy rates).

RESULTS

11 studies were included (two studies assessing solid pancreas outcomes between older vs reference-aged donors and nine studies assessing outcomes between older vs reference-aged recipients). Seven of 11 studies were judged to be at high risk of bias. Primary and secondary outcomes were not significantly different between recipient age groups in nine studies. A sensitivity analysis of older vs reference-aged studies excluding studies at high risk of bias also showed non-inferior primary and secondary outcomes at one year. Two studies comparing outcomes by donor age showed worse graft survival but non-inferior patient survival with older donors.

CONCLUSION

Increased donor or recipient age alone should not absolutely contraindicate solid pancreas transplantation, especially if other risk predictors are minimised. This article is protected by copyright. All rights reserved.

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.

Outcomes of pancreas transplantation in older versus younger recipients: a comparative analysis

PURPOSE

The feasibility of pancreas transplantation (PT) in older recipients remains a matter of debate. We examined the influence of recipient age on PT outcomes and identified the prognostic factors for older recipients.

METHODS

We compared the outcomes of PT in recipients aged < 50 years (younger group; n = 285) with those in recipients aged ≥ 50 years (older group; n = 94). Prognostic factors in the older group were analyzed by a logistic regression model and the influence of recipient age on survival outcomes were analyzed using propensity score matching.

RESULTS

The patient survival rate was significantly worse in the older group (P < 0.001). Patient death from infection or/and multiple organ failure or cardiac/cerebrovascular events was also more frequent in the older group than in the younger group (P = 0.012 and P = 0.045, respectively). A longer duration of diabetes was an independent risk factor of 1-year mortality in the older group. In a propensity score-matched comparison, the older recipients (n = 77) had significantly poorer survival than the younger recipients (n = 77) (P = 0.026).

CONCLUSIONS

PT should be considered with appropriate caution, especially for older recipients with a long duration of diabetes.

Recipient age and outcomes following simultaneous pancreas-kidney transplantation in the new millennium: Single-center experience and review of the literature

The influence of recipient age on outcomes following simultaneous pancreas-kidney transplantation (SPKT) in the modern era is uncertain.

METHODS

We retrospectively studied 255 patients undergoing SPKT from 11/01 to 8/20. Recipients were stratified according to age group: age <30 years (n = 16); age 30-39 years (n = 91); age 40-49 years (n = 86) and age ≥50 years (n = 62 [24.3%], including 9 patients ≥60 years of age).

RESULTS

Three-month and one-year outcomes were comparable. The eight-year patient survival rate was lowest in the oldest age group (47.6% vs 78% in the 3 younger groups combined, p < .001). However, eight-year kidney and pancreas graft survival rates were comparable in the youngest and oldest age groups combined (36.5% and 32.7%, respectively), but inferior to those in the middle 2 groups combined (62% and 50%, respectively, both p < .05). Death-censored kidney and pancreas graft survival rates increased from youngest to oldest recipient age category because of a higher incidence of death with functioning grafts (22.6% in oldest group compared to 8.3% in the 3 younger groups combined, p = .005).

CONCLUSIONS

Recipient age did not appear to significantly influence early outcomes following SPKT. Late outcomes are similar in younger and older recipients, but inferior to the middle 2 age groups.

Bioengineered Islet Cell Transplantation

Purpose of Review

β cell replacement via whole pancreas or islet transplantation has greatly evolved for the cure of type 1 diabetes. Both these strategies are however still affected by several limitations. Pancreas bioengineering holds the potential to overcome these hurdles aiming to repair and regenerate β cell compartment. In this review, we detail the state-of-the-art and recent progress in the bioengineering field applied to diabetes research.

Recent Findings

The primary target of pancreatic bioengineering is to manufacture a construct supporting insulin activity in vivo. Scaffold-base technique, 3D bioprinting, macro-devices, insulin-secreting organoids, and pancreas-on-chip represent the most promising technologies for pancreatic bioengineering.

Summary

There are several factors affecting the clinical application of these technologies, and studies reported so far are encouraging but need to be optimized. Nevertheless pancreas bioengineering is evolving very quickly and its combination with stem cell research developments can only accelerate this trend.

Pancreas transplantation would be easy if the recipients were not diabetic: A practical guide to post-operative management of diabetic complications in pancreas transplant recipients

Diabetes mellitus remains a major public health problem throughout the United States with over $300 billion spent in total cost of care annually. In addition to being a leading cost of kidney failure, diabetes causes a host of secondary hyperglycemic-related complications including gastroparesis and orthostatic hypotension. While pancreas transplantation has been established as an effective treatment for diabetes, providing long-term normoglycemia in recipients, the secondary complications of diabetes mellitus persist complicating the post-operative course of an otherwise successful pancreas transplantation. This review describes the mechanism and impact of diabetic gastroparesis and orthostatic hypotension in the post-operative course of pancreas transplant patients and analyzes the various treatment modalities, based on current data and extensive experience at our institution, to treat these respective complications. While gastroparesis and orthostatic hypotension remain challenging post-operative conditions, the establishment of institutional protocols and step-up treatment algorithms can help define more effective therapies.

Pancreatic islet reserve in type 1 diabetes

Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by pancreatic islet β cell loss and dysfunction resulting in insulin deficiency and hyperglycemia. During a presymptomatic phase of established β cell autoimmunity, β cell loss may first be evident through assessment of β cell secretory capacity, a measure of functional β cell mass. Reduction in pancreatic islet β cell reserve eventually manifests as impaired first-phase insulin response to glucose and abnormal glucose tolerance, which progresses until the functional capacity for β cell secretion can no longer meet the demand for insulin to control glycemia. A functional β cell mass of ∼25% of normal may be required to avoid symptomatic T1D but is already associated with dysregulated glucagon secretion. With symptomatic T1D, stimulated C-peptide levels >0.60 ng/mL (0.200 pmol/mL) indicate the presence of clinically meaningful residual β cell function for contributing to glycemic control, although even higher residual C-peptide appears necessary for evidencing glucose-dependent islet β and α cell function that may contribute to maintaining (near)normal glycemia. β cell replacement by islet transplantation can restore a physiologic reserve capacity for insulin secretion, confirming thresholds for functional β cell mass required for independence from insulin therapy.

Pancreas transplant versus islet transplant versus insulin pump therapy: in which patients and when?

PURPOSE OF REVIEW

The aim of the present review is to gather recent reports on the use of pancreas and islet transplantation and conventional insulin therapy for treating patients experiencing diabetes and its related complications. The present review directs attention to the current status, challenges and perspectives of these therapies and sheds light on potential future cellular therapies.

RECENT FINDINGS

The risks and benefits of diabetes treatment modalities continue to evolve, altering the risk versus benefit calculation for patients. As continuous subcutaneous insulin infusion and monitoring technologies demonstrate increasing effectiveness in achieving better diabetes control and reducing hypoglycemia frequency, so are pancreas and islet transplantation improving and becoming more effective and safer. Both beta-cell replacement therapies, however, are limited by a dependence on immunosuppression and a shortage of cadaver donors, restricting more widespread and safer deployment. Based on the effectiveness of clinical beta-cell replacement for lengthening lifespan and improving quality of life, scientists are aggressively investigating alternative cell sources, transplant platforms, and means of preventing immunological damage of transplanted cells to overcome these principle limitations.

SUMMARY

Essential goals of diabetes therapy are euglycemia, avoidance of hypoglycemia, and prevention or stabilization of end-organ damage. With these goals in mind, all therapeutic options should be considered.

Patients with highly unstable type 1 diabetes eligible for islet transplantation can be managed with a closed-loop insulin delivery system: A series of N-of-1 randomized controlled trials

AIM

To compare the efficacy of the closed-loop Diabeloop for highly unstable diabetes (DBLHU) system with the open-loop predictive low glucose suspend (PLGS) system in patients with highly unstable type 1 diabetes (T1D) who experience acute metabolic events.

METHODS

DBLHU-WP10 was an interventional, controlled, randomized, open-label study that comprised two cycles of N-of-1 trials (2-of-1 trials). Each trial consisted of two crossover 4-week periods of treatment with either DBLHU or PLGS in randomized order. The primary outcome was the percentage of time spent in the 70-180 mg/dL glucose range (time in range [TIR]).

RESULTS

Five out of seven randomized patients completed the aggregated 2-of-1 trials. TIR was significantly higher with DBLHU (73.3% ± 1.7%) compared with PLGS (43.5% ± 1.7%; P < .0001). The percentage of time below 70 mg/dL was significantly lower with DBLHU (0.9% ± 0.4%) versus PLGS (3.7% ± 0.4%; P < .0001). DBLHU was also significantly superior to PLGS in reducing hyperglycaemic excursions and improving almost all other secondary outcomes, including glucose variability and satisfaction score. No adverse event could be related to the experimental treatment.

CONCLUSIONS

DBLHU was superior to PLGS in improving the metabolic control of patients with highly unstable T1D who require an islet or pancreas transplant but who either have a contraindication or refuse to consent.

Late complications of pancreas transplant

To summarize the long-term complications after pancreas transplantation that affect graft function, a literature search was carried out on the long-term complications of pancreatic transplantation, namely, complications from postoperative 3^rd mo onwards, in terms of loss of graft function, late infection and vascular complications as pseudoaneurysms. The most relevant reviews and studies were selected to obtain the current evidence on these topics. The definition of graft failure varies among different studies, so it is difficult to evaluate, a standardized definition is of utmost importance to know the magnitude of the problem in all worldwide series. Chronic rejection is the main cause of long-term graft failure, occurring in 10% of patients. From the 3rd mo of transplantation onwards, the main risk factor for late infections is immunosuppression, and patients have opportunistic infections like: Cytomegalovirus, hepatitis B and C viruses, Epstein-Barr virus and varicella-zoster virus; opportunistic bacteria, reactivation of latent infections as tuberculosis or fungal infections. Complete preoperative studies and serological tests should be made in all recipients to avoid these infections, adding perioperative prophylactic treatments when indicated. Pseudoaneurysm are uncommon, but one of the main causes of late bleeding, which can be fatal. The treatment should be performed with radiological endovascular approaches or open surgery in case of failure. Despite all therapeutic options for the complications mentioned above, transplantectomy is a necessary option in approximately 50% of relaparotomies, especially in life-threatening complications. Late complications in pancreatic transplantation threatens long-term graft function. An exhaustive follow-up as well as a correct immunosuppression protocol are necessary for prevention.

Early protocol computer tomography and endovascular interventions in pancreas transplantation

BACKGROUND

Early vascular complications following pancreatic transplantation are not uncommon (3%-8%). Typically, cross-sectional imaging is requested in response to clinical change. We instituted a change in protocol to request imaging pre-emptively to identify patients with thrombotic complications.

METHODS

In 2013, protocol computer tomography angiography (CTA) at days 3-5 and day 10 following pancreas transplantation was introduced. A retrospective analysis of all pancreas transplants performed at our institution from January 2001 to May 2019 was undertaken.

RESULTS

A total of 115 patients received pancreas transplants during this time period. A total of 78 received pancreas transplant without routine CTA and 37 patients with the new protocol. Following the change in protocol, we detected a high number of subclinical thromboses (41.7%). There was a significant decrease in invasive intervention for thrombosis (78.6% before vs 30.8% after, p = .02), and graft survival was significantly higher (61.5% before vs 86.1% after, p = .04). There was also a significant reduction in the number of graft failures (all-cause) where thrombosis was present (23.4% before vs 5.6% after, p = .02). Patient survival was unaffected (p = .48).

CONCLUSIONS

Implementation of early protocol CTA identifies a large number of patients with subclinical graft thromboses that are more amenable to conservative management and significantly reduces the requirement for invasive intervention.

Development and validation of a quantitative electron microscopy score to assess acute cellular stress in the human exocrine pancreas

The pancreas is particularly sensitive to acute cellular stress, but this has been difficult to evaluate using light microscopy. Pancreatic ischaemia associated with deceased organ donation negatively impacts whole‐organ and isolated‐islet transplantation outcomes. Post‐mortem changes have also hampered accurate interpretation of ante‐mortem pancreatic pathology. A rigorous histological scoring system accurately quantifying ischaemia is required to experimentally evaluate innovations in organ preservation and to increase rigour in clinical/research evaluation of underlying pancreatic pathology. We developed and validated an unbiased electron microscopy (EM) score of acute pancreatic exocrine cellular stress in deceased organ donor cohorts (development [n = 28] and validation [n = 16]). Standardised assessment led to clearly described numerical scores (0–3) for nuclear, mitochondrial and endoplasmic reticulum (ER) morphology and intracellular vacuolisation; with a maximum (worst) aggregate total score of 12. In the Validation cohort, a trend towards higher scores was observed for tail versus head regions (nucleus score following donation after brainstem death [DBD]: head 0.67 ± 0.19; tail 0.86 ± 0.11; p = 0.027) and donation after circulatory death (DCD) versus DBD (mitochondrial score: DCD (head + tail) 2.59 ± 0.16; DBD (head + tail) 2.38 ± 0.21; p = 0.004). Significant mitochondrial changes were seen ubiquitously even with short cold ischaemia, whereas nuclear and vacuolisation changes remained mild even after prolonged ischaemia. ER score correlated with cold ischaemia time (CIT) following DBD (pancreatic tail region: r = 0.796; p = 0.018). No relationships between CIT and EM scores were observed following DCD. In conclusion, we have developed and validated a novel EM score providing standardised quantitative assessment of subcellular ultrastructural morphology in pancreatic acinar cells. This provides a robust novel tool for gold standard measurement of acute cellular stress in studies evaluating surrogate measures of peri‐transplant ischaemia, organ preservation technologies and in samples obtained for detailed pathological examination of underlying pancreatic pathology.

Early worsening of diabetic retinopathy after simultaneous pancreas and kidney transplantation-Myth or reality?

Early worsening of diabetic retinopathy due to sudden glucose normalization is a feared complication of pancreas transplantation; however, its rate or severity has not been studied prospectively. We followed up 43 pancreas and kidney recipients for a composite endpoint comprising new need for laser therapy, newly diagnosed proliferation, macular edema, visual acuity worsening, and blindness over 12 months. Although 37% of patients met this primary endpoint, its severity was rather low. Mean central retinal thickness and proportion of patients with subclinical macular edema increased significantly, with spontaneous resolution in half of them. Visual acuity did not change. There was no significant difference in the absolute glycated hemoglobin (HbA1c) drop, age, and diabetes duration between the patients who met and those who did not meet the primary endpoint, but a higher proportion of patients with worsening had a recent history of laser treatment. Retinopathy remained stable in 62.8% of patients. In 26%, the visual acuity significantly improved. Although retinopathy worsening was documented in more than one-third of patients, its evolution was not related to the magnitude of metabolic change; rather, it corresponded to the expected natural course of retinopathy. Nonetheless, comprehensive ophthalmologic care should be a substantial component of the recipient management.

Transplant strategies for type 1 diabetes: whole pancreas, islet and porcine beta cell therapies

Whole-organ pancreas and islet transplantations are performed in a highly selected group of patients with diabetes mellitus, primarily those with type 1 diabetes mellitus, complicated by recurrent severe hypoglycaemia or renal failure requiring kidney transplantation. Clinical accessibility to pancreases or islets, and patient characteristics and therapeutic goals, may dictate choice of procedure. Pancreas transplantation is most often performed simultaneous with a kidney transplant, but patients with particularly labile type 1 diabetes may be considered for a pancreas transplant alone. While highly successful at restoring insulin independence, pancreas transplants carry the significant risks of major surgery and immunosuppression. Islet transplantation is a relatively minor procedure, usually performed for labile type 1 diabetes with severe hypoglycaemia. It is highly successful at resolving hypoglycaemia, but more than one pancreas donor may be required for insulin independence. Both pancreas and islet transplantation are limited in applicability by a paucity of deceased donors. Pigs provide one promising replenishable source of islets. Porcine islets can successfully reverse diabetes mellitus in non-human primates under the appropriate immunosuppressive conditions, with promise for eventually translating this success to a larger population of patients with diabetes mellitus in the future. Graphical abstract.

Normal Pancreas Graft Appearance in Magnetic Resonance Diffusion Tensor Imaging (DTI)

BACKGROUND The main purpose of diagnostic imaging after pancreas transplantation is to exclude potential complications. As long as standard anatomical imaging such as sonography, contrast-enhanced computed tomography, and magnetic resonance imaging (MRI) are sufficient to display macroscopic vasculature, early changes within the graft caused by insufficient microperfusion will not be displayed for evaluation. MATERIAL AND METHODS Patients with pancreas allograft function in good condition were included in the study. No specific preparation was demanded before the MRI examination. The results of MRI were correlated with Igls criteria. It was a preliminary study to examine diffusion tensor imaging (DTI) value and safety in pancreas transplantation. RESULTS Our results indicated that higher fractional anisotropy (FA) values of the graft's head were associated with delayed graft function and insulin intake. We also compared grafts' images in early and late periods and found differences in T1 signal intensity values. DTI is a reliable noninvasive tool, requiring no contrast agent, to assess graft microstructure in correlation with its function, with FA values showing the most consistent results. By Igls criteria, no graft failure, 76% had optimal function, 10% had good function, and 14% had marginal function. CONCLUSIONS Our results suggest that DTI can be safely used in patients after pancreas transplantation and is advantageous in detecting early as well as late postoperative complications such as intra-abdominal fluid collection, malperfusion, and ischemia of the graft. Our findings correspond with clinical condition and Igls criteria. DTI is free of ionizing agents and is safe for kidney grafts.

eHealth Interventions for Solid Organ Transplant Recipients: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND

Lack of support for self-management may contribute to adverse health outcomes. eHealth has the potential to support self-management, but evidence in solid organ transplantation remains unclear. This review aims to evaluate the benefits and harms of eHealth interventions to support self-management in solid organ transplant recipients.

METHODS

We searched Cochrane Central Register of Controlled Trials, MEDLINE, and Embase databases for randomized trials of eHealth interventions in solid organ transplant recipients. We calculated the risk ratios or standardized mean difference of outcomes, and summary estimates were determined using random-effects models. The Cochrane risk of bias tool and Grading of Recommendations, Assessment, Development, and Evaluations were used to assess trial quality.

RESULTS

Twenty-one trials from 6 countries involving 2114 participants were included. Compared with standard care, eHealth interventions improved medication adherence (risk ratio, 1.34; CI, 1.12-2.56; I = 75%) and self-monitoring behavior (risk ratio, 2.58; CI, 1.56-4.27; I = 0%) up to 12 mo posttransplant. The treatment effects were largely consistent across different subgroups except for intervention functionality and mode of delivery. The effects on other outcomes were uncertain. Nine trials reported harms. The overall risk of bias was considered high or unclear, and the quality of evidence was low to very low for all outcomes.

CONCLUSIONS

eHealth interventions may improve medication adherence and self-monitoring behavior in the short term, but high-quality intervention studies are needed to determine whether eHealth will improve long-term patient-relevant outcomes.

Advances Toward Engineering Functionally Mature Human Pluripotent Stem Cell-Derived β Cells

Human stem cell-derived β (SC-β) cells have the potential to revolutionize diabetes treatment through disease modeling, drug screening, and cellular therapy. SC-β cells are likely to represent an early clinical translation of differentiated human pluripotent stem cells (hPSC). In 2014, two groups generated the first in vitro-differentiated glucose-responsive SC-β cells, but their functional maturation at the time was low. This review will discuss recent advances in the engineering of SC-β cells to understand and improve SC-β cell differentiation and functional maturation, particularly new differentiation strategies achieving dynamic glucose-responsive insulin secretion with rapid correction to normoglycemia when transplanted into diabetic mice.

Anti-Hla donor-specific antibody monitoring in pancreas transplantation: Role of protocol biopsies

In kidney transplantation, de novo donor-specific antibodies (DSA) correlate with poor graft survival, and Consensus Guidelines recommend a protocol biopsy. In pancreas transplantation, DSA are also associated with poor graft outcomes; however, there are no recommendations on protocol biopsies. We started an antibody screening protocol on pancreas transplant patients at 0, 3, 6, 12 months, and yearly. Patients with DSA or high MFI non-DSA were considered for protocol biopsies of both organs. Results: 143 pancreas recipients were screened. 84 patients had negative antibodies throughout the study, 11 patients were found to have antibodies at graft dysfunction, and 48 patients had positive antibodies at screening without acute organ dysfunction (study group). Among the 30 non-DSA patients, 9 had protocol simultaneous pancreas and kidney biopsies performed with negative results in all of them. In contrast, among the 18 DSA patients, 15 had these biopsies performed, and 47% presented with subclinical rejection of the kidney, the pancreas, or both. In addition, some of the DSA patients without a protocol biopsy presented with rejection during the first 15 months of follow-up. Conclusion: We conclude that protocol biopsies of both grafts may play a role in the follow-up of pancreas transplant patients with de novo DSA appearance.