Search

International audience; Many variables impact islet isolation, including pancreas ischemia time. The ischemia time upper limit that should be respected to avoid a negative impact on the isolation outcome is not well defined. We have performed a retrospective analysis of all islet isolations in our center between 2008 and 2018. Total ischemia time, cold ischemia time, and organ removal time were analyzed. Isolation success was defined as an islet yield ≥200 000 IEQ. Of the 452 pancreases included, 288 (64%) were successfully isolated. Probability of isolation success showed a significant decrease after 8 hours of total ischemia time, 7 hours of cold ischemia time, and 80 minutes of organ removal time. Although we observed an impact of ischemia time on islet yield, a probability of isolation success of 50% was still present even when total ischemia time exceeds 12 hours. Posttransplantation clinical outcomes were assessed in 32 recipients and no significant difference was found regardless of ischemia time. These data indicate that although shorter ischemia times are associated with better islet isolation outcomes, total ischemia time >12 hours can provide excellent results in appropriately selected donors.

This study aimed to assess the global mapping risk of human islet isolation, using a failure mode and effect analysis (FMEA), and highlight the impact of quality assurance procedures on the risk level of criticality. Risks were scored using the risk priority number (RPN) scoring method. The risk level of criticality was made based on RPN and led to risk classification (low to critical). A raw risk analysis and a risk control analysis (with control means and quality assurance performance) were undertaken. The process of human islet isolation was divided into 11 steps, and 230 risks were identified. Analysis of the highest RPN of each of the 11 steps showed that the 4 highest risks were related to the pancreas digestion and islet purification stages. After implementation of reduction measures and controls, critical and severe risks were reduced by 3-fold and by 2-fold, respectively, so that 90% of risks could be considered as low to moderate. FMEA has proven to be a powerful approach for the identification of weaknesses in the islet isolation processes. The results demonstrated the importance of staff qualification and continuous training and supported the contribution of the quality assurance system to risk reduction.

Islet transplantation has experienced significant progress over the past decades, transforming an experimental procedure into an established option for selected patients with type 1 diabetes. Compared to solid organ transplantation, the mandatory multistep conditioning of the pancreas prior to islet transplantation, and the technological infrastructure and know-how it implies, have encouraged the creation of multicenter networks early in the development of islet transplantation programs. The first islet transplantation network created was GRAGIL. It is an example of successful collaboration across national borders, and has contributed and adapted its practices to the successive advances in the field. This chapter describes the rationale for an islet transplantation network, the logistics involved, and the different challenges faced and addressed by the network. These points are illustrated by the several clinical trials completed by GRAGIL and discussed from the network point of view and in perspective with concurrent advances in the field.

The microbiological safety of islet preparations is paramount. Preservation medium contamination is frequent, and its impact on islet yield and function remains unclear. Microbiological samples collected during islet isolations from 2006 to 2016 were analyzed and correlated to isolation and allo- and autotransplantation outcomes. Microbial contamination of preservation medium was found in 64.4% of processed donor pancreases (291/452). We identified 464 microorganisms including Staphylococcus (253/464, 54.5%), Streptococcus (31/464, 6.7%), and Candida species (25/464, 5.4%). Microbial contamination was associated with longer warm and cold ischemia times and lower numbers of postpurification islet equivalents, purity, transplant rate, and stimulation index (all P < 0.05). Six percent of the preparations accepted for transplantation showed microbial contamination after isolation (12/200); 9 of 12 were Candida species. Six patients were transplanted with a sample with late microbial growth discovered after the infusion. Insulin independence rate was not affected. This risk of transplanting a contaminated islets preparation was reduced by half following the implementation of an additional sampling after 24 h of islet culture. Pancreas preservation fluid microbial contamination is associated with lower transplant rate and poorer in vitro function, but not with changes in graft survival. Culture medium testing 1 day after isolation reduces the risk of incidental transplantation with contaminated islets.

Allogeneic islet of Langerhans transplantation is a recognized beta-cell replacement therapy for patients affected by type 1 diabetes mellitus. Type 1 diabetes mellitus is a condition associated with an increased risk of adverse outcomes for pregnant women and fetuses We report the case of a 29 year-old woman with type 1 diabetes mellitus, who underwent successful allogeneic islet transplantation with simultaneous kidney transplantation. She achieved durable insulin independence after two islet infusions. Pregnancy was desired and planned 2 years after last islet infusion. Multidisciplinary monitoring of pregnancy was carried out and immunosuppressive regimen was adapted. Euglycemia was maintained throughout pregnancy without the need for exogenous insulin. After an uneventful pregnancy, she delivered on term an otherwise healthy male child with imperforate anus that was immediately surgically corrected. In conclusion, allogeneic islet transplantation is a suitable treatment for women of childbearing age with complicated type 1 diabetes mellitus, allowing physiologic glycemic control during pregnancy with a low risk of graft loss. This target can only be achieved by a tight multidisciplinary follow-up, including immunosuppressive therapy adaptation and adequate diabetes and obstetrical monitoring. This article is protected by copyright. All rights reserved.

International audience; Background Islet transplantation is indicated for patients with type 1 diabetes with severe hypoglycaemia or after kidney transplantation. We did a randomised trial to assess the efficacy and safety of islet transplantation compared with insulin therapy in these patients. Methods In this multicentre, open-label, randomised controlled trial, we randomly assigned (1:1) patients with type 1 diabetes at 15 university hospitals to receive immediate islet transplantation or intensive insulin therapy (followed by delayed islet transplantation). Eligible patients were aged 18-65 years and had severe hypoglycaemia or hypoglycaemia unawareness, or kidney grafts with poor glycaemic control. We used computer-generated randomisation, stratified by centre and type of patient. Islet recipients were scheduled to receive 11000 islet equivalents per kg bodyweight in one to three infusions. The primary outcome was proportion of patients with a modified (beta-score (in which an overall score of 0 was not allocated when stimulated C-peptide was negative) of 6 or higher at 6 months after first islet infusion in the immediate transplantation group or 6 months after randomisation in the insulin group. The primary analysis included all patients who received the allocated intervention; safety was assessed in all patients who received islet infusions. This trial is registered with ClinicalTrials.gov, number NCT01148680, and is completed. Findings Between July 8, 2010, and July 29, 2013, 50 patients were randomly assigned to immediate islet transplantation (n=26) or insulin treatment (n=24), of whom three (one in the immediate islet transplantation group and two in the insulin therapy group) did not receive the allocated intervention. Median follow-up was 184 days (IQR 181-186) in the immediate transplantation group and 185 days (172-201) in the insulin therapy group. At 6 months, 16 (64% [95% CI 43-82]) of 25 patients in the immediate islet transplantation group had a modified (beta-score of 6 or higher versus none (0% [0-15]) of the 22 patients in the insulin group (p\textless0.0001). At 12 months after first infusion, bleeding complications had occurred in four (7% [2-18]) of 55 infusions, and a decrease in median glomerular filtration rate from 90-5 mL/min (IQR 76-6-94-0) to 71-8 mL/min (59-0-89-0) was observed in islet recipients who had not previously received a kidney graft and from 63 .0 mL/min (55.0-71-0) to 57. 0 mL/min (45-5-65 . 1) in islet recipients who had previously received a kidney graft. Interpretation For the indications assessed in this study, islet transplantation effectively improves metabolic outcomes. Although studies with longer-term follow-up are needed, islet transplantation seems to be a valid option for patients with severe, unstable type 1 diabetes who are not responding to intensive medical treatments. However, immunosuppression can affect kidney function, necessitating careful selection of patients. Copyright (C) 2018 Elsevier Ltd. All rights reserved.

Islet transplantation is an effective treatment for selected patients with type 1 diabetes. However, an accurate test still lacks for the early detection of graft rejection. Blood samples were prospectively collected in four university centers (Geneva, Grenoble, Montpellier, and Strasbourg). Peripheral blood mononuclear cells were stimulated with donor splenocytes in the presence of interleukin-2. After 24 h of incubation, interferon-γ (IFN-γ) ELISpot analysis was performed. After a total of 5 days of incubation, cell proliferation was assessed by fluorescence-activated cell sorting (FACS) analysis for Ki-67. Immunological events were correlated with adverse metabolic events determined by loss of ≥1 point of β-score and/or an increased insulin intake ≥10%. Twenty-five patients were analyzed; 14 were recipients of islets alone, and 11 combined with kidney. Overall, 76% (19/25) reached insulin independence at one point during a mean follow-up of 30.7 months. IFN-γ ELISpot showed no detectable correlation with adverse metabolic events [area under the curve (AUC) = 0.57]. Similarly, cell proliferation analysis showed no detectable correlation with adverse metabolic events (CD3+/ CD4+ AUC = 0.54; CD3+/CD8+ AUC = 0.55; CD3-/CD56+ AUC = 0.50). CD3-/CD56+ cell proliferation was significantly higher in patients with combined kidney transplantation versus islet alone (6 months, p = 0.010; 12 months, p = 0.016; and 24 months, p = 0.018). Donor antigen-stimulated IFN-γ production and cell proliferation do not predict adverse metabolic events after islet transplantation. This suggests that the volume of transplanted islets is too small to produce a detectable systemic immune response and/or that alloimmune rejection is not the sole reason for the loss of islet graft function.

The aim of our study was to assess cell trafficking and early events after intraportal islet transplantation. Sprague-Dawley rat islets were incubated for various times, with various concentrations of 2-[F]fluoro-2deoxy-D-glucose (FDG), and in presence of various glucose concentrations. FDG-labeled syngeneic islets or FDG alone were injected in rats. Radioactivity was measured in the liver and in various organs by positron-emission tomography for 6 hours. FDG uptake increased with incubation time or FDG concentration and decreased in presence of glucose. In vivo, all islets implanted in the liver, with an uptake 4.4 times higher than controls (44.2% vs. 10.1%, P=0.02). Radioactivity in the liver decreased at the same rate after injection of labeled-islets and FDG alone. Ex vivo labeling of islets and imaging of posttransplant early events were feasible. Islets engrafted exclusively in the liver. No islet loss could be demonstrated 6 hours after transplantation.

Anti-human leukocyte antigen (HLA) antibody could lead to humoral rejection and a decrease in graft survival after kidney transplantation. A recent report has suggested that islet transplantation alone is associated with a high rate of sensitization. The withdrawal of the immunosuppressive therapy because of the progressive nonfunction of the islets could explain the high rate of sensitization. Because the specific risk of immunization of multiple islet infusions remains unknown, we studied the immunization rate in our cohort of multiple islet infusions transplant recipients. De novo anti-HLA antibodies were analyzed in 37 patients after islets alone (n=8), islet-after-kidney (n=13), and simultaneous islet-kidney (n=16) transplantation by solid phase assays over time. The rate of immunization was 10.8% that is comparable with the risk of immunization after kidney transplantation alone. Multiple islet infusions do not represent a specific risk for the development of anti-HLA antibodies after combined kidney-islets transplantation.

BACKGROUND: Since the Edmonton trial in 2000, increasing numbers of transplant centers have been implementing islet transplantation programs. Some institutions have elected to associate in multicenter networks, such as the Swiss-French GRAGIL (Groupe Rhin-Rh?Alpes-Gen? pour la Transplantation d'Ilots de Langerhans) consortium. METHODS: All pancreata offers to the University of Geneva Cell Isolation and Transplantation Center from within the network in 2002 and 2003 were reviewed. Islet preparations were attributed to the most suitable recipient on a centrally managed waiting list. All shipments were performed by ambulance in less than 5 hr. RESULTS: Over the period of study, 260 pancreata were offered, from a total of 1,304 cadaveric donors in the four allocation regions (20%). Fifty-two patients were on the waiting list at any time during this 2-year period. The percentage of organs offered varied in the range of 0.5% to 42%, depending on region of origin, with a correlation with number of patients on the waiting list in each region. Of these, 104 (40%) were accepted for processing. Ninety-two pancreata were actually processed, resulting in 42 islet preparations being transplanted. The number of international equivalents of transplanted preparations was 378,500+/-16,000 versus 165,400+/-15,400 (P

Background The aim of the study was to analyze the possibility of xenogeneic islet retransplantation using costimulatory blockade. Methods Streptozotocin-induced diabetic mice were transplanted under the kidney capsule with human islets. Mice were nephrectomized and retransplanted with 1000 human islets under the contralateral kidney capsule 14 days later. Four groups were performed group I, first and second Tx without MR1; group II, first Tx without MR1, second Tx with MR1; group III, first Tx with MR1, second Tx without MR1; group IV, first and second Tx with MR1. A control group was transplanted only once without MR1 with human islets. After second Tx, cross-matches between recipient, serum and human lymphocyte were done for detection of antidonor antibodies. Results In the control group, mean graft survival was 13 (±7) days. In group I, mean graft survival was 5 ± 3 days. In group II, mean graft survival was 16 ± 13 days. In group III, mean graft survival was 81 ± 22 days. In group IV, no rejection were recorded and all graft survived more than 120 days. Pretransplant cross-matches were negative. In groups I and II all cross-matches were positive, while none were positive in group IV. Conclusion Retransplantation of xenogeneic islets was associated with accelerated rejection. After presensitization, MR1 was unable to induce tolerance to a second Tx. MR1 given at the first Tx only allowed prolonged survival of the second Tx, but rejection still occurred. MR1 given at first and second Tx allowed long-term survival of retransplanted xenoislets and prevented occurrence of antidonor antibodies.