Non-heart-beating organ donors: a potential source of islets for transplantation?

Utility of Islet Cell Preparations From Donor Pancreases After Euthanasia

Patients fulfilling criteria for euthanasia can choose to donate their organs after circulatory death [donors after euthanasia (DCD V)]. This study assesses the outcome of islet cell isolation from DCD V pancreases. A procedure for DCD V procurement provided 13 pancreases preserved in Institut Georges Lopez-1 preservation solution and following acirculatory warm ischemia time under 10 minutes. Islet cell isolation outcomes are compared with those from reference donors after brain death (DBD, n = 234) and a cohort of donors after controlled circulatory death (DCD III, n = 29) procured under the same conditions. Islet cell isolation from DCD V organs resulted in better in vitro outcome than for selected DCD III or reference DBD organs. A 50% higher average beta cell number before and after culture and a higher average beta cell purity (35% vs 24% and 25%) was observed, which led to more frequent selection for our clinical protocol (77% of isolates vs 50%). The functional capacity of a DCD V islet cell preparation was illustrated by its in vivo effect following intraportal transplantation in a type 1 diabetes patient: injection of 2 million beta cells/kg body weight (1,900 IEQ/kg body weight) at 39% insulin purity resulted in an implant with functional beta cell mass that represented 30% of that in non-diabetic controls. In conclusion, this study describes procurement and preservation conditions for donor organs after euthanasia, which allow preparation of cultured islet cells, that more frequently meet criteria for clinical use than those from DBD or DCD III organs.

Clinical use of donation after circulatory death pancreas for islet transplantation

Due to a shortage of donation after brain death (DBD) organs, donation after circulatory death (DCD) is increasingly performed. In the field of islet transplantation, there is uncertainty regarding the suitability of DCD pancreas in terms of islet yield and function after islet isolation. The aim of this study was to investigate the potential use of DCD pancreas for islet transplantation. Islet isolation procedures from 126 category 3 DCD and 258 DBD pancreas were performed in a 9-year period. Islet yield after isolation was significantly lower for DCD compared to DBD pancreas (395 515 islet equivalents [IEQ] and 480 017 IEQ, respectively; p = .003). The decrease in IEQ during 2 days of culture was not different between the two groups. Warm ischemia time was not related to DCD islet yield. In vitro insulin secretion after a glucose challenge was similar between DCD and DBD islets. After islet transplantation, DCD islet graft recipients had similar graft function (AUC C-peptide) during mixed meal tolerance tests and Igls score compared to DBD graft recipients. In conclusion, DCD islets can be considered for clinical islet transplantation.

Hypothermic oxygenated machine perfusion of the human pancreas for clinical islet isolation: a prospective feasibility study

Due to an increasing scarcity of pancreases with optimal donor characteristics, islet isolation centers utilize pancreases from extended criteria donors, such as from donation after circulatory death (DCD) donors, which are particularly susceptible to prolonged cold ischemia time (CIT). We hypothesized that hypothermic machine perfusion (HMP) can safely increase CIT. Five human DCD pancreases were subjected to 6 h of oxygenated HMP. Perfusion parameters, apoptosis, and edema were measured prior to islet isolation. Five human DBD pancreases were evaluated after static cold storage (SCS). Islet viability, and in vitro and in vivo functionality in diabetic mice were analyzed. Islets were isolated from HMP pancreases after 13.4 h [12.9–14.5] CIT and after 9.2 h [6.5–12.5] CIT from SCS pancreases. Histological analysis of the pancreatic tissue showed that HMP did not induce edema nor apoptosis. Islets maintained >90% viable during culture, and an appropriate in vitro and in vivo function in mice was demonstrated after HMP. The current study design does not permit to demonstrate that oxygenated HMP allows for cold ischemia extension; however, the successful isolation of functional islets from discarded human DCD pancreases after performing 6 h of oxygenated HMP indicates that oxygenated HMP may be a useful technology for better preservation of pancreases.

Lower beta cell yield from donor pancreases after controlled circulatory death prevented by shortening acirculatory warm ischemia time and by using IGL-1 cold preservation solution

Organs from donors after controlled circulatory death (DCD III) exhibit a higher risk for graft dysfunction due to an initial period of warm ischemia. This procurement condition can also affect the yield of beta cells in islet isolates from donor pancreases, and hence their use for transplantation. The present study uses data collected and generated by our Beta Cell Bank to compare the number of beta cells in isolates from DCD III (n = 141) with that from donors after brain death (DBD, n = 609), before and after culture, and examines the influence of donor and procurement variables. Beta cell number per DCD III-organ was significantly lower (58 x 106 versus 84 x 106 beta cells per DBD-organ; p < 0.001) but their purity (24% insulin positive cells) and insulin content (17 μg / 106 beta cells in DCD III-organs versus 19 μg / 106 beta cells in DBD-organs) were similar. Beta cell number correlated negatively with duration of acirculatory warm ischemia time above 10 min; for shorter acirculatory warm ischemia time, DCD III-organs did not exhibit a lower beta cell yield (74 x 106 beta cells). Use of Institut Georges Lopez-1 cold preservation solution instead of University of Wisconsin solution or histidine-tryptophan-ketoglutarate also protected against the loss in beta cell yield from DCD III-organs (86 x 106 for IGL-1 versus 54 x 106 and 65 x 106 beta cells respectively, p = 0.042). Multivariate analysis indicates that both limitation of acirculatory warm ischemia time and use of IGL-1 prevent the reduced beta cell yield in islet cell isolates from DCD III-organs.

The Effects of Using Pancreases Obtained from Brain-Dead Donors for Clinical Islet Transplantation in Japan

Background: The pool of brain-dead donors (BDDs) was increased with the revision to the relevant law in 2010, and islet transplantation from BDDs was started in 2013. The present study assessed the influence of using pancreases from BDDs on islet transplantation in Japan. Methods: The donor information registered with the secretariat of islet transplants from 2012 was reviewed, and the results of 86 clinical islet isolations performed in Japan between 2003 and 2018 with non-heart-beating donors (NHBDs) (n = 71) and BDDs (n = 15) were investigated. Results: The number of cases for which donor information was registered with the secretariat of islet transplants increased to 1.84 cases/month from 2013 to 2018 in comparison to 1.44/month in 2012, when only NHBDs were used. The median pancreatic islet yield was 275,550 IEQ (Islet equivalents) in the NHBD group but 362,700 in the BDD group, which amounted to a statistically significant difference (p = 0.02). As a result, 38/71 cases (53.5%) were achieved successful islet isolation (>5000 IEQ per recipient weight (kg)) was achieved in 38/71 cases (53.5%) in the NHBD group, and 12/15 cases (80.0%) in the BDD group; thus, the rate of successful islet transplantation was higher in the BDD group. Conclusion: The use of pancreases from BDDs has increased the overall number of cases for which donor information is registered with the secretariat of islet transplants and has improved the performance of islet isolation, thereby increasing the probability of successfully achieving islet transplantation.

Clinical islet isolation and transplantation outcomes with deceased cardiac death donors are similar to neurological determination of death donors

In islet transplantation, deceased cardiac death (DCD) donation has been identified as a potential extended source. There are currently no studies comparing outcomes between these categories, and our goal was to compare islet isolation success rates and transplantation outcomes between DCD and neurological determination of death (NDD) donors. Islet isolations from 15 DCD and 418 NDD were performed in our centre between September 2008 and September 2014. Donor variables, islet yields, metabolic function of isolated isled and insulin requirements at 1-month post-transplant were compared. Compared to NDD, pancreata from DCD were more often procured locally and donors required less vasopressive support (P < 0.001 and P = 0.023, respectively), but the other variables were similar between groups. Pre- and postpurification islet yields were similar between NDD and DCD (576 vs. 608 × 10(3) islet equivalent, P = 0.628 and 386 vs. 379, P = 0.881, respectively). The metabolic function was similar between NDD and DCD, as well as the mean decrease in insulin requirement at 1-month post-transplantation (NDD: 64.82%; DCD: 60.17% reduction, P = 0.517). These results support the broader use of DCD pancreata for islet isolation. A much larger DCD islet experience will be required to truly determine noninferiority of both short- and long-term outcomes.

Utilization of organs from donors after circulatory death for vascularized pancreas and islet of Langerhans transplantation: recommendations from an expert group

Donation after circulatory death (DCD) donors are increasingly being used as a source of pancreas allografts for vascularized organ and islet transplantation. We provide practice guidelines aiming to increase DCD pancreas utilization. We review risk assessment and donor selection criteria. We report suggested factors in donor and recipient clinical management and provide an overview of the activities and outcomes of vascularized pancreas and islet transplantation.

Improvement of pancreatic islet cell isolation for transplantation

Pancreatic islet transplantation is a promising treatment for diabetes but still faces several challenges. Poor islet isolation efficiency and poor long-term insulin independence are currently two major issues, although donor shortage and the need for immunosuppressants also need to be addressed. We established the Kyoto islet isolation method (KIIM), which has enabled us to isolate and transplant islets even from non-heart-beating donors. KIIM involves 1) cooling the donor pancreas in situ, 2) preserving the ducts with modified Kyoto solution, 3) using a modified two-layer pancreas preservation method, and 4) adjusting the density of the density gradient centrifugation and using an iodixanol-based solution for purification. KIIM has enabled us to transplant 17 islet preparations out of 21 isolations (an 81% success rate). All transplanted islets functioned, and all transplanted patients had improved glycemic control without hypoglycemic unawareness. Recently, we used KIIM for islet isolation from a brain-dead donor at Baylor, which resulted in a very high islet yield (789,984 IE) with high viability (100% by fluorescein diacetate/propidium iodide staining and a stimulation index of 4.7). This preliminary evidence suggests that KIIM may also be promising for islet isolation from brain-dead donors. In addition, to assess engrafted islet mass, we developed a secretory unit of islet transplant objects (SUITO) index: fasting C-peptide (ng/dL) / [fasting blood glucose (mg/dL) - 63] x 1500. This simple index has enabled us to monitor the engrafted islet mass. This index should be useful when deciding whether to perform additional islet transplantations to maintain insulin independence. Poor islet isolation efficacy and poor long-term results could be resolved with ongoing research.

Pancreas procurement and preservation for islet transplantation: personal considerations

Pancreatic islet transplantation is a promising option for the treatment of type 1 diabetic patients. After the successful demonstration of the Edmonton protocol, islet transplantation has advanced significantly on several fronts, including improved pancreas procurement and preservation systems. Since we frequently use pancreata from donors after cardiac death in Japan,we have applied the in situ regional organ cooling system for pancreas procurement to reduce the warm ischemic time. To reduce the apoptosis of pancreatic tissue during cold preservation, we have applied the ductal injection of preservation solution. For pancreas preservation, we use modified Kyoto solution, which is advantageous at trypsin inhibition and less collagenase inhibition. In this paper, we show pancreas procurement and preservation in our group for islet transplantation.

Islet transplantation using donors after cardiac death: report of the Japan Islet Transplantation Registry

BACKGROUND

This report summarizes outcomes of islet transplantation employing donors after cardiac death (DCD) between 2004 and 2007 as reported to the Japan Islet Transplantation Registry.

METHOD

Sixty-five islet isolations were performed for 34 transplantations in 18 patients with insulin-dependent diabetes mellitus, including two patients who had prior kidney transplantation. All but one donor (64/65) was DCD at the time of harvesting.

RESULTS

Factors influencing criteria for islet release included duration of low blood pressure of the donor, cold ischemic time, and usage of Kyoto solution for preservation. Multivariate analysis selected usage of Kyoto solution as most important. Of the 18 recipients, 8, 4, and 6 recipients received 1, 2, and 3 islet infusions, respectively. Overall graft survival defined as C-peptide level more than or equal to 0.3 ng/mL was 76.5%, 47.1%, and 33.6% at 1, 2, and 3 years, respectively, whereas corresponding graft survival after multiple transplantations was 100%, 80.0%, and 57.1%, respectively. All recipients remained free of severe hypoglycemia while three achieved insulin independence for 14, 79, and 215 days. HbA1c levels and requirement of exogenous insulin were significantly improved in all patients.

CONCLUSION

Islet transplantation employing DCD can ameliorate severe hypoglycemic episodes, significantly improve HbA1c levels, sustain significant levels of C-peptide, and achieve insulin independence after multiple transplantations. Thus, DCD can be an important resource for islet transplantation if used under strict releasing criteria and in multiple transplantations, particularly in countries where heart-beating donors are not readily available.

A new preservation solution (SCOT 15) Improves the islet isolation process from pancreata of non-heart-beating donors: a Murine model

INTRODUCTION

Due to the organ shortage, there is increased use of organs harvested from non-heart-beating donors (NHBD). These organs have been subjected to a period of warm ischemia that is most deleterious to functional recovery. We have designed a new preservation solution, "Solution de Conservation des Organes et des Tissus" (SCOT 15; Macopharma, Tourcoing, France) which contains an extracellular ionic composition including PEG 20 kD (15 g/L) as a colloid.

METHODS

Our objective was to compare SCOT 15 with University of Wisconsin (UW) solution or islet culture medium CMRL 1066 + 1% of Bovine Serum Albumin (BSA), as the working and preservation solution for islet isolation from pancreata subjected to warm ischemia using a murine model.

RESULTS

Warm ischemia decreased the islet yield and cellular viability regardless of the preservation solution. Either when the pancreas was or was not subjected to warm ischemia, the best islet yield was obtained with SCOT 15 (P < .05 vs UW or CMRL 1066). The same results were observed for islet viability as assessed using the 3,(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test; namely, better viability with SCOT 15 as compared with UW or CMRL 1066 (P < .01).

CONCLUSION

In a murine model SCOT 15 was a better preservation solution for islet isolation than UW solution or culture medium (CMRL 1066).

Can 'extreme' pancreas donors expand the donor pool?

PURPOSE OF REVIEW

The present review investigates donor qualities that impact pancreas and islet transplantation, with a focus on donors that have been historically underutilized, including those of extreme age, extreme size, and donors after cardiac death.

RECENT FINDINGS

The increasing waiting time caused by the shortage of available pancreata and the growing number of patients with uncontrolled diabetes has led to the expansion of acceptance criteria for transplantable pancreata. The possible increased perioperative risks and/or foreshortened graft survival associated with the use of 'extreme' donors should be weighed against the mortality of uremic diabetics on the waiting list and the risk of dying from a hypoglycemic-unawareness episode. Current data have shown that pediatric pancreas donors are associated with excellent outcomes. Selected donors up to 50 years of age are suitable for both islet and pancreas transplantation. Obese donors are more appropriate as islet donors, and donors after cardiac death provide an underutilized source of pancreata for transplantation, with clinical results that are identical to those observed from ideal donors.

SUMMARY

Donor selection in pancreas transplantation significantly impacts outcome, yet the use of extended criteria donors can provide results comparable with those of ideal donors.

Analysis of donor- and isolation-related variables from non-heart-beating donors (NHBDs) using the Kyoto islet isolation method

Recently, we demonstrated that islet transplantation from non-heart-beating donors (NHBDs) using the Kyoto islet isolation method (KIIM) successfully reversed patients' diabetes state. In this study, we evaluated the effects of donor- and isolation-related variables on islet isolation results from NHBDs by KIIM. Twenty-one islet preparations from the pancreata of NHBDs were isolated by KIIM. Islet preparations that met transplantation criteria and achieved improved patient diabetes control after transplantation were defined as successful isolations. Potential risk factors deemed to affect islet isolation results, such as age, gender, body mass index, hospital stay, donors' blood biochemical tests, a modified pancreata procurement method, and isolation and purification procedure-related variables, were analyzed. Seventeen out of 21 islet isolations (81%) were successful isolations. Postpurification islet yield was 447,639 +/- 39,902 islet equivalents (IE) in the successful isolation group and 108,007 +/- 31,532 IE in the failure group. Donor age was significantly younger in the success group (41.9 +/- 4.0 years old in the success group vs. 57.5 +/- 2.2 years old in the failure group, p = 0.003). Chronic pancreatitis significantly decreased islet yields (p = 0.006). Phase I time was significantly shorter (p = 0.010) and undigested tissue volume was significantly smaller (p = 0.020) in the success group. Purity was in positive correlation to postpurification islet yield, while donor age was in reverse correlation to postpurification islet yield. KIIM enables us to perform islet transplantation from NHBDs; however, the decision to use pancreata from older donors or those with chronic pancreatitis requires careful consideration.

Human islets derived from donors after cardiac death are fully biofunctional

Islets from brain-dead donors (BDDs) are being used in the treatment of Type 1 diabetes. However, both donor numbers and islet survival are limited. We explored the clinical potential for islets from non-heart-beating donors (NHBDs), who have lower circulating cytokines, by comparing islets from 10 NHBDs against 12 identically-isolated islets from BDDs over the same time period. The quantity and quality of islets from NHBDs was good. NHBD yielded approximately 12.6% more islets than those of BDDs (505,000 +/- 84,230 vs. 400,970 +/- 172,430 islet equivalent number [IEQ]/pancreas, p = 0.01) with comparable viability. ATP and GTP contents were lower (6.026 +/- 3.076 vs. 18.105 +/- 7.8 nM/mg protein, p = 0.01 and 1.52 +/- 0.87 vs. 3.378 +/- 0.83 nM/mg protein, p = 0.04) and correlated negatively to warm ischemia time (R(2)= 0.8022 and R(2)= 0.7996, respectively). Islets from NHBDs took longer to control hyperglycemia in diabetic mice, but were equally able to sustain euglycemia. With a warm ischemia time (WIT) of <or=25 min, islets from NHBDs are at least as competent as islets from BDDs and should be suitable for clinical use.

Estado actual del trasplante de islotes pancreáticos

Due to the numerous advances in islet transplantation in the last few years, clinical outcomes following this procedure are continually improving. Novel immunosuppression protocols, improved donor and recipient selection, and careful attention to the process of organ extraction, preservation and islet isolation have contributed to long-term success. The present article reviews the results of clinical islet transplantation and their relationship with the different advances introduced. The use of new islet sources such as living and non-heart-beating donors, as well as recent advances in our knowledge of the mechanisms of rejection and its prevention, are also reviewed.

Procurement of the Human Pancreas for Pancreatic Islet Transplantation from Marginal Cadaver Donors

BACKGROUND

Recent advances in pancreatic islet transplantation (PIT) have contributed significantly to the treatment of patients with type 1 diabetes. The specific aim of this study was to develop an effective technique for the procurement of pancreas for PIT from nonheart-beating-donor (NHBDs).

METHODS

Between January 2004 and August 2004, eight human pancreata were procured and processed for isolation of islets at a cell processing center. After confirmation of brain death status, a double balloon catheter was inserted to prevent warm ischemic damage to the donor pancreas by using an in situ regional organ cooling system that was originally developed for procurement of kidneys. The catheter position of the cooling system was modified specifically for the pancreas and kidney. Furthermore, we worked in cooperation with a kidney procurement team to protect the pancreas during kidney procurement.

RESULTS

Warm ischemic time could be controlled with the modified in situ regional cooling system at 3.0 +/- 0.8 min (mean +/- SE). The operations for procurement of the kidneys and pancreata lasted 45.6 +/- 3.6 min and 10.6 +/- 1.8 min, respectively. Islet yield per isolation was 444,426 +/- 35,172 IE (islet equivalent). All eight cases met the criteria for PIT based on the Edmonton protocol.

CONCLUSION

We developed a novel procurement technique in cooperation with our kidney procurement team. This protocol for the procurement of pancreas and kidney from a NHBD enabled us to transplant islets into a type 1 diabetic patient and kidney into a renal failure patient.

Outcomes of pancreas transplantation in the United States using cardiac-death donors

Organs donated after cardiac death (DCD) are used to expand the donor pool. We analyzed the outcomes in the United States of pancreatic transplantation of organs from DCD donors performed between 1993 and 2003. We used the OPTN/UNOS Registry to compare outcomes of primary pancreas allografts from DCD donors and donors after brain death (DBD). The primary endpoints were graft failure and patient death. A national survey regarding the use of DCD donors in pancreas transplantation was conducted among the directors of pancreas transplant centers. Data were obtained on 47 simultaneous pancreas-kidney transplants (SPK) and 10 solitary pancreas transplants from DCD donors and on 2431 SPK and 1607 solitary pancreas transplants from DBD donors. Recipients of a SPK transplants from DCD and DBD donors had equivalent patient and graft survival rates at 1, 3 and 5 years. For recipients of SPK transplants, the wait for organs from DCD donors was significantly shorter than that for organs from DBD donors. SPK recipients of organs from DCD donors had longer hospital stays than did recipients of organs from DBD donors. With renal allografts, the incidence of delayed graft function was almost four times higher with organs from DCD donors than with organs from DBD donors. Selective use of organs from DCD donors is safe for pancreas transplantation.

Pancreatic islet cell transplantation using non-heart-beating donors (NHBDs)

Recent dramatic improvements in clinical islet cell transplantation demonstrated by the Edmonton group have increased the demand for this treatment, and donor shortage could become a major problem. Utilization of marginal donors could alleviate the donor shortage, and non-heart-beating donors (NHBDs) might be good resources. The University of Pennsylvania group demonstrated that it was possible to isolate islets from NHBDs, and the group actually transplanted islets from NHBDs, for the first time. The patient became insulin-independent; however, there had been no more cases using NHBDs until our group initiated islet transplantations from NHBDs in Japan. In order to utilize NHBDs effectively, we modified the standard islet isolation method. These modifications included minimizing the warm ischemic time, the use of trypsin inhibition during isolation, carrying out density measurement before purification and the use of a less toxic islet purification solution. With these modifications we were able to transplant nine of ten islet preparations from ten NHBDs (90%), into five type-1 diabetic patients. The first transplantation was performed on April 7, 2004 (the first time in Japan), and this patient became insulin-independent after the second islet transplantation (first time in Japan). All patients showed improved glycemic control and reduced insulin requirements, without hypoglycemic events. We also performed living-donor islet transplantation, with our modified islet isolation protocol, on January 19, 2005. The improved islet isolation protocol enabled us to perform effective islet transplantations from NHBDs, and it also enabled us to perform the living-donor islet transplantation.

Simultaneous pancreas-kidney transplantation from donation after cardiac death: successful long-term outcomes

OBJECTIVE

The outcomes of simultaneous pancreas-kidney (SPK) transplantation with donor organs procured from donation after cardiac death (DCD) are compared with transplants performed with donor organs recovered from donation after brain death (DBD).

SUMMARY BACKGROUND DATA

Concerns exist regarding the utilization of pancreata obtained from DCD donors. While it is known that DCD kidneys will have a higher rate of DGF, long-term functional graft survival data for DCD pancreata have not been reported.

METHODS

A retrospective review of all DCD SPK transplants performed at a single center was undertaken.

RESULTS

Patient, pancreas, and kidney survival at 5 years were similar between DCD and DBD organs. Pancreas function and outcomes were indistinguishable between the 2 modes of procurement. As expected, the DCD kidneys had an elevated rate of DGF, which had no significant long-term clinical impact.

CONCLUSION

SPK transplantation using selected DCD donors is a safe and viable method to expand the organ pool for transplantation.

In Situ Cooling of Pancreata From Non–Heart-Beating Donors Prior to Procurement for Islet Transplantation

BACKGROUND

The specific aim of this study was to develop an effective technique for pancreas procurement for islet transplantation from a non-heart-beating donor (NHBD).

METHODS

Between January 2004 and November 2004, 11 human pancreata were procured and processed for islet isolation at a cell processing center. After confirmation of brain-death status, a double-balloon catheter was inserted to prevent warm ischemic damage to the donor pancreas by using an in situ regional organ cooling system that was originally developed for kidney procurement.

RESULTS

Warm ischemic time was controlled with the modified in situ regional cooling system at 6.0 +/- 0.9 minutes (mean +/- SE). The operations for procurement of the kidneys and pancreata lasted 48.1 +/- 3.6 minutes and 9.9 +/- 4.8 minutes, respectively. The islet yield per isolation was 396,767 +/- 142,842 IE (islet equivalents). Ten of the 11 cases met the criteria for pancreatic islet transplantation based on the Edmonton protocol.

CONCLUSIONS

We developed a novel procurement technique in cooperation with our kidney procurement team. This protocol for the procurement of pancreas and kidney from an NHBD enabled us to transplant islets into a type 1 diabetic patient and kidney into a renal failure patient.

The Start of an Islet Transplantation Program in Japan

In Japan, pancreas donation had become possible from cadaveric donor sources, both heart-beating or non-heart-beating (NHB). Pancreas allografts have been distributed in the organ allocation system of the Japan Organ Transplant Network. Meanwhile, islet transplantation has been categorized as a tissue transplantation; it is free from legal restraints. Thus, pancreata for islet isolation must be obtained from NHB donors. Herein we report the starting program and preliminary results of islet transplantation in Japan. Selection and listing criteria for transplantation include regional priority, ABO blood type, previous islet transplant status with insulin independence, and a longer waiting time. Five institutes in Japan (Fukushima, Chiba, Kyoto, Kobe, and Fukuoka) are prepared to start programs. A two-layer cold storage method using perfluorocarbons and UW solution is recommended for pancreas preservation. Islet isolation and purification procedures are performed according to institute-specific protocol. Immunosuppression is based on sirolimus/tacrolimus combined with basiliximab induction. Two or three consecutive infusions of >5000 IE/kg are planned for each recipient until achieving insulin independence. Twenty-seven isolations and 14 transplants were performed in eight non-insulin-dependent diabetes mellitus (IDDM) recipients. Almost all (26 of 27) were NHB donors. All recipients are free from hypoglycemic episode after transplantation. One of these recipients is insulin independent; the others are currently on minimal doses of exogenous insulin. The feasibility of islet transplantation using NHB donors was confirmed using a two-layer cold storage method and a steroid-free immunosuppressive protocol, with a high rate of graft function.

Donor Care before Pancreatic Tissue Transplantation

Publications are reviewed to identify factors related to donor care that may optimize the function of pancreatic tissue (whole or segmental organ or islet cells) after transplantation. Short cold ischemia time, avoidance of hypotension, and treatment of donor hyperglycemia appear to be beneficial, although additional properly designed studies are needed to verify those findings.

Retrieving organs from non-heart-beating organ donors: a review of medical and ethical issues

PURPOSE

The increasing gap between numbers of individuals awaiting organ replacement surgery and the supply of organs available for transplant underpins attempts to increase the number of organs available. One practice, used in other countries, is the recovery of organs from non-heart-beating organ donors (NHBD). The purpose of this review is to discuss ethical issues surrounding the use of organs from these donors.

SOURCE

Narrative review from selected Medline references, and other published reports.

PRINCIPAL FINDINGS

NHBD protocols have been established in many countries including the United States. Despite numerous publications, and extensive debate in the literature, significant ethical issues remain unresolved in the retrieval of organs from donors that have died from cessation of cardiac activity. The ethical concerns primarily arise in the determination of death, the tension between the time constraints on recovering organs viable for transplantation, and procedures to enhance organ viability. Despite a concerted effort in the United States, less than half of the organ procurement organizations have NHBD protocols.

CONCLUSION

Canadian centres can learn from the difficulties encountered in other centres that have developed NHBD protocols. A moratorium on Canadian NHBD protocols should be considered until a National consensus reflecting Canadian values has been undertaken.

Flexible management of enzymatic digestion improves human islet isolation outcome from sub-optimal donor pancreata

Worldwide growing interest in reproducing the result of the Edmonton protocol in islet transplantation trials poses the problem of paucity of donors to supply sufficient amount of islets for clinical use. Improved outcomes include finding better ways to obtain higher yields from every donor organ processed and the possibility of extending islet isolation processing to glands of suboptimal quality. In order to optimize enzymatic digestion of marginal donor organs, we have modified the technique of tissue collection following enzymatic digestion of human pancreatic organs, allowing for reduced time of exposure of free islets to warm Liberase trade mark solution. Our results indicate that better controlled exposure to enzyme yields: (i) higher islet numbers; (ii) complete dissociation of all parts of pancreatic tissue; (iii) successful islet harvest from organs otherwise excluded. We also show that by limiting the exposure of free islets to enzyme solution, islet fragmentation and loss of insulin content are reduced. We further support evidence that enzymatic digestion may contribute to impairment of insulin secretory capacity of the islets in vitro during culture.

Functional and structural integrity of porcine pancreatic grafts subjected to a period of warm ischemia and cold preservation with histidine-tryptophan-ketoglutarate (custodiol) or University of Wisconsin solution

BACKGROUND

University of Wisconsin (UW) solution (Viaspan) is currently used to preserve organs from nonheartbeating donors. Histidine-tryptophan-ketoglutarate (HTK) solution (Custodiol) is of proven efficacy in experimental pancreas preservation, but its efficacy in combined warm ischemia (WI) and cold ischemia (CI) is unknown. The viability of HTK-preserved porcine pancreatic grafts was assessed after various periods of WI and compared with grafts flushed and preserved with UW solution.

METHODS

A total of 14 pigs were used: G1 (n=4, UW) and G2 (n=4, HTK) with 15-min WI and 16-hr cold storage; G3 (n=3, UW) and G4 (n=3, HTK) with 30-min WI and 16-hr cold storage.

RESULTS

All animals in G1 and G2 were normoglycemic, whereas only 66% of pancreases were functioning in G3 and G4. HTK perfusion was associated with increased wet weight. Transient hyperinsulinemia was noted in all the groups on postoperative day 1 (mean range: 8.9-12.4 microU/L). Postoperative serum amylase and lipase were more pronounced in G3 and G4. However, HTK-stored grafts exhibited less evidence of biochemical pancreatitis as compared with UW-stored grafts on the first postoperative day in the group with 15-min WI. Mean K values of intravenous glucose tolerance tests on postoperative day 14 were similar in both groups. Vascular congestion was uniformly observed and was considered a typical feature of WI.

CONCLUSIONS

Porcine pancreatic grafts are viable after 16-hr CI following 15-min WI in this experimental nonheartbeating donor model. HTK solution seems to provide reliable graft function in this setting and to be equivalent to UW.

Myocardial viability twenty-four hours after orthotopic heart transplantation from non-heart-beating donors

OBJECTIVES

Using a new preservation strategy, we investigated the performance of hearts from non-heart-beating donors during an observation period of 24 hours after orthotopic heart transplantation in a pig model.

METHODS

In the control group (n = 6) beating donor hearts were harvested with Bretschneider's HTK solution and transplanted orthotopically without reperfusion modifications. In the non-heart-beating donor group (n = 6) hearts were perfused with leukocyte-depleted blood cardioplegia after 30 minutes of normothermic ischemia. Blood cardioplegia was supplemented with a sodium-hydrogen exchange inhibitor and adenosine. After transplantation, a second controlled reperfusion with blood cardioplegia was performed.

RESULTS

Preload recruitable stroke work of the left ventricle 24 hours after transplantation in the control versus non-heart-beating donor group was 108% +/- 24% versus 103% +/- 18% of baseline values. Myocardial blood flow of the left and right ventricle was increased to 146% +/- 32% and 176% +/- 51% in the control group versus 176% +/- 29% and 194% +/- 27% in the non-heart-beating donor group. Myocardial oxygen consumption was 11.2 +/- 2.1 versus 12.8 +/- 2.2 mL/100 g per minute at baseline and 11.6 +/- 2.6 versus 13.2 +/- 3.1 mL/100 g per minute after 24 hours (not significant). Histologic examination with Luxol fast blue staining revealed that 2.6% +/- 4.8% of myocytes in the control group versus 1.8% +/- 1.9% in the non-heart-beating donor group were damaged irreversibly.

CONCLUSIONS

Recovery of donor hearts from non-heart-beating donors is comparable with recovery of organs harvested from heart-beating donors if the above-mentioned preservation technique is used. These results could encourage the use of marginal donor hearts and help to expand the limited donor pool.

The use of non-heart-beating donors for isolated pancreatic islet transplantation

Recent improvements in isolated islet transplantation indicate that this therapy may ultimately prove applicable to patients with type I diabetes. An obstacle preventing widespread application of islet transplantation is an insufficient supply of cadaveric pancreata. Non-heart-beating donors (NHBDs) are generally not deemed suitable for whole-organ pancreas donation and could provide a significant source of pancreata for islet transplantation. Isolated pancreatic islets prepared from 10 NHBDs were compared with those procured from 10 brain-dead donors (BDDs). The success of the isolation for the two groups was analyzed for preparation purity, quality, and recovered islet mass. The function of NHBD and BDD islets was evaluated using in vitro and in vivo assays. On the basis of the results of this analysis, an NHBD isolated islet allograft was performed in a type I diabetic. The recovery of islets from NHBDs was comparable to that of control BDDs. In vitro assessment of NHBD islet function revealed function-equivalent BDD islets, and NHBD islets transplanted to non-obese diabetic-severe combined immunodeficient (NOD-SCID) mice efficiently reversed diabetes. Transplantation of 446,320 islet equivalents (IEq) (8,500 IEq/kg of recipient body weight) from a single NHBD successfully reversed the diabetes of a type I diabetic recipient. Normally functioning pancreatic islets can be isolated successfully from NHBDs. A single donor transplant from an NHBD resulted in a state of stable insulin independence in a type I diabetic recipient. These results indicate that NHBDs may provide an as yet untapped source of pancreatic tissue for preparation of isolated islets for clinical transplantation.

Islet transplantation, stem cells, and transfusion medicine

Despite the widespread use of exogenous insulin, morbidity and mortality caused by type 1 diabetes mellitus (DM) continue to place a significant burden on society, both in terms of human suffering and cost. The transplantation of vascularized pancreas, usually performed concurrently with renal transplantation, can cure type 1 DM, as shown by results in more than 15000 such transplants over about 30 years. Transplantation of isolated pancreatic islets, instead of the whole organ, however, offers an attractive alternative that minimizes surgery and its complications. Although islet transplantation initially met with only modest success (only about 9% insulin independence at 1 year posttransplant), recent changes in patient selection criteria, number and treatment of islets transplanted, and better immunosuppressive regimens dramatically improved the results; spawning widespread enthusiasm for islet transplantation. Despite this promise, organ/islet availability remains an important limitation to this technology. A solution to the problem of limited materials for transplantation may be in the use of stem/progenitor cells. This article reviews the background of the current enthusiasm for pancreatic islet cell transplantation, highlights future research trends in the field, and suggests that the new islet-related cellular therapies belong within the domain of transfusion medicine.

Pancreatic Islet Cell Transplantation

Pancreatic islet cell transplantation as a treatment for diabetes has hitherto been confined to small patient cohorts with limited success. This article summarizes the results of islet cell transplantation before and after the advent of the new 'Edmonton protocol' of immunosuppression and management of the donor pancreas. Adopting this regimen has achieved unprecedented success and renewed interest in this potential cure for diabetes. Central to recent improvements in the technique has been the transplantation of an adequate islet mass. Improved methods to procure, isolate, and purify islets for clinical use are now being adopted as a new 'gold standard'. The use of new immunosuppressive drugs has further improved clinical results. Corticosteroid sparing-based regimens, and agents such as humanized monoclonal antibodies, are likely to form the mainstay of immunosuppressive protocols with the aim of achieving donor-specific tolerance. Alternative sources of islet cells are also required to expand the technique in an era of reduced numbers of donor pancreata. Manipulation of stem cells and xenotransplantation may yet yield sufficient islets to overcome the problem of donor shortage. Islet cell transplantation now forms the basis of a prospective multicenter trial under the aegis of the Immune Tolerance Network. The results of this are awaited, but it appears that islet cell transplantation may yet emerge as an effective treatment option for some members of the diabetic population.

Human islet cell transplantation--future prospects

BACKGROUND

Islet transplantation has the potential to cure diabetes mellitus. Nevertheless despite successful reversal of diabetes in many small animal models, the clinical situation has been far more challenging. The aim of this review is to discuss why insulin-independence after islet allotransplantation has been so difficult to achieve.

METHODS

A literature review was undertaken using Medline from 1975 to July 2000. Results reported to the International Islet Transplant Registry (ITR) up to December 1998 were also analysed.

RESULTS

Up to December 1998, 405 islet allotransplants have been reported the ITR. Of those accurately documented between 1990 and 1998 (n = 267) only 12% have achieved insulin-independence (greater than 7 days). However with refined peri-transplant protocols insulin independence at 1 year can reach 20%.

CONCLUSIONS

There are many factors which can explain the failure of achieving insulin-independence after islet allotransplantation. These include the use of diabetogenic immunosuppressive agents to abrogate both islet allo-immunity and auto-immunity, the critical islet mass to achieve insulin-independence and the detrimental effects of transplanting islets in an ectopic site. However recent evidence most notably from the Edmonton group demonstrates that islet allotransplantation still has great potential to become an established treatment option for diabetic patients.