Sophie Borot

Five-Year Metabolic, Functional, and Safety Results of Patients With Type 1 Diabetes Transplanted With Allogenic Islets Within the Swiss-French GRAGIL Network

OBJECTIVE To describe the 5-year outcomes of islet transplantation within the Swiss-French GRAGIL Network. RESEARCH DESIGN AND METHODS Retrospective analysis of all subjects enrolled in the GRAGIL-1c and GRAGIL-2 islet transplantation trials. Parameters related to metabolic control, graft function, and safety outcomes were studied. RESULTS Forty-four patients received islet transplantation (islet transplantation alone [ITA] 24 patients [54.5%], islet after kidney [IAK] transplantation 20 patients [45.5%]) between September 2003 and April 2010. Recipients received a total islet mass of 9,715.75 ± 3,444.40 IEQ/kg. Thirty-four patients completed a 5-year follow-up, and 10 patients completed a 4-year follow-up. At 1, 4, and 5 years after islet transplantation, respectively, 83%, 67%, and 58% of the ITA recipients and 80%, 70%, and 60% of the IAK transplant recipients reached HbA1c under 7% (53 mmol/mol) and were free of severe hypoglycemia, while none of the ITA recipients and only 10% of the IAK transplant recipients met this composite criterion at the preinfusion stage. Thirty-three of 44 patients (75%) experienced insulin independence during the entire follow-up period, with a median duration of insulin independence of 19.25 months (interquartile range 2–58). Twenty-nine of 44 recipients (66%) exhibited at least one adverse event; 18 of 55 adverse events (33%) were possibly related to immunosuppression; and complications related to the islet infusion (n = 84) occurred in 10 recipients (11.9%). CONCLUSIONS In a large cohort with a 5-year follow-up and in a multicenter network setting, islet transplantation was safe and efficient in restoring good and lasting glycemic control and preventing severe hypoglycemia in patients with type 1 diabetes.

Assessment of adrenal function in cirrhotic patients using concentration of serum-free and salivary cortisol

Objective: Because over 90% of serum cortisol is bound to albumin and corticosteroid‐binding globulin (CBG), changes in these proteins can affect measures of serum total cortisol levels in cirrhotics without altering serum‐free and salivary cortisol concentrations.

The liver receptor homolog-1 (LRH-1) is expressed in human islets and protects β-cells against stress-induced apoptosis

Liver receptor homolog (LRH-1) is an orphan nuclear receptor (NR5A2) that regulates cholesterol homeostasis and cell plasticity in endodermal-derived tissues. Estrogen increases LRH-1 expression conveying cell protection and proliferation. Independently, estrogen also protects isolated human islets against cytokine-induced apoptosis. Herein, we demonstrate that LRH-1 is expressed in islets, including β-cells, and that transcript levels are modulated by 17β-estradiol through the estrogen receptor (ER)α but not ERβ signaling pathway. Repression of LRH-1 by siRNA abrogated the protective effect conveyed by estrogen on rat islets against cytokines. Adenoviral-mediated overexpression of LRH-1 in human islets did not alter proliferation but conferred protection against cytokines and streptozotocin-induced apoptosis. Expression levels of the cell cycle genes cyclin D1 and cyclin E1 as well as the antiapoptotic gene bcl-xl were unaltered in LRH-1 expressing islets. In contrast, the steroidogenic enzymes CYP11A1 and CYP11B1 involved in glucocorticoid biosynthesis were both stimulated in transduced islets. In parallel, graded overexpression of LRH-1 dose-dependently impaired glucose-induced insulin secretion. Our results demonstrate the crucial role of the estrogen target gene nr5a2 in protecting human islets against-stressed-induced apoptosis. We postulate that this effect is mediated through increased glucocorticoid production that blunts the pro-inflammatory response of islets.

Impact of the number of infusions on 2-year results of islet-after-kidney transplantation in the GRAGIL network.

Background. Insulin independence after islet transplantation is generally achieved after multiple infusions. However, single infusion would increase the number of recipients. Our aim was to evaluate the results of islet-after-kidney transplantation according to the number of infusions. Methods. Islets were isolated at the Geneva University, shipped, and transplanted into French patients from the Swiss-French GRAGIL network, on the “Edmonton” immunosuppression protocol between 2004 and 2010. Results. Nineteen patients were transplanted with 33 preparations. Fifteen patients reached 24 months follow-up; eight subjects were single-graft recipients and seven were double-graft recipients. Finally, single-graft recipients received a median of 5312 islet equivalents/kg (5186–6388) vs. 10,564 (10,054–11,375) for double-graft recipients (P=0.0003) with similar islet mass at first infusion. Insulin independence was achieved in five of eight single-graft subjects (62.5%) versus five of seven in double-graft subjects (71.4%), not significant. Median insulin independence duration was 4.7 (3.1–15.2) months after one infusion vs. 19 (9.6–20.8) months after two infusions (not significant). At 24 months posttransplant, comparing single- with double-graft patients, insulin doses were 0.23 (0.11–0.34) U/kg vs. 0.02 (0.0–0.23) U/kg, P=0.11; HbA1c was 6.5% (5.9%–6.8%) vs. 6.2% (5.9%–6.3%), P=0.16; and basal C-peptide was 302 (143–480) pmol/L vs. 599 (393–806) pmol/L, P=0.05. Only 37.5% of single-graft patients had a &bgr;-score ≥4 compared with 100% of double-graft patients (P=0.03). Two recipients experienced postinfusion bleeding, and two patients (13%) showed renal dysfunction in the absence of biopsy-proven rejection. Conclusions. One infusion achieves good glycemic control and sometimes insulin independence. However, double-graft patients remain insulin-free longer, tend to have lower HbA1c, and show better graft function 24 months after transplant.

Survival of Free and Encapsulated Human and Rat Islet Xenografts Transplanted into the Mouse Bone Marrow

Bone marrow was recently proposed as an alternative and potentially immune-privileged site for pancreatic islet transplantation. The aim of the present study was to assess the survival and rejection mechanisms of free and encapsulated xenogeneic islets transplanted into the medullary cavity of the femur, or under the kidney capsule of streptozotocin-induced diabetic C57BL/6 mice. The median survival of free rat islets transplanted into the bone marrow or under the kidney capsule was 9 and 14 days, respectively, whereas that of free human islets was shorter, 7 days (bone marrow) and 10 days (kidney capsule). Infiltrating CD8+ T cells and redistributed CD4+ T cells, and macrophages were detected around the transplanted islets in bone sections. Recipient mouse splenocytes proliferated in response to donor rat stimulator cells. One month after transplantation under both kidney capsule or into bone marrow, encapsulated rat islets had induced a similar degree of fibrotic reaction and still contained insulin positive cells. In conclusion, we successfully established a small animal model for xenogeneic islet transplantation into the bone marrow. The rejection of xenogeneic islets was associated with local and systemic T cell responses and macrophage recruitment. Although there was no evidence for immune-privilege, the bone marrow may represent a feasible site for encapsulated xenogeneic islet transplantation.

Transplanted Human Pancreatic Islets After Long‐Term Insulin Independence

Long‐term insulin independence after islets of Langerhans transplantation is rarely achieved. The aims of this study were to identify the histological and immunological features of islets transplanted in a type 1 diabetic patient who died of a cerebral hemorrhage after >13 years insulin independence. Islets were pooled from two donors with respectively one and five HLA mismatches. Insulin‐positive islets were found throughout the right and left liver, and absent in the pancreas. Two‐ and three‐dimensional analysis showed that islets lost their initial rounded and compact morphology, had a mean diameter of 136 μm and were constituted of an unfolded epithelial band of 39.1 μm. Leukocyte phenotyping showed no evidence of a tolerogenic environment in the islet‐containing portal spaces. Finally, HLA typing of microdissected islets showed HLA from the best matched donor in all 23 microdissection samples, compared to 1/23 for the least matched donor. This case report demonstrates that allogeneic islets can survive over 13 years while maintaining insulin independence. Allogeneic islets had unique morphologic features and implanted in the liver regardless of their size. Finally, our results suggest that, in this case, rejection had been prevalent over autoimmunity, although this hypothesis warrants further investigation.

Temozolomide treatment can improve overall survival in aggressive pituitary tumors and pituitary carcinomas

OBJECTIVES Only few retrospective studies have reported an efficacy rate of temozolomide (TMZ) in pituitary tumors (PT), all around 50%. However, the long-term survival of treated patients is rarely evaluated. We therefore aimed to describe the use of TMZ on PT in clinical practice and evaluate the long-term survival. DESIGN Multicenter retrospective study by members of the French Society of Endocrinology. METHODS Forty-three patients (14 women) treated with TMZ between 2006 and 2016 were included. Most tumors were corticotroph (n = 23) or lactotroph (n = 13), and 14 were carcinomas. Clinical/pathological characteristics of PT, as well as data from treatment evaluation and from the last follow-up were recorded. A partial response was considered as a decrease in the maximal tumor diameter by more than 30% and/or in the hormonal rate by more than 50% at the end of treatment. RESULTS The median treatment duration was 6.5 cycles (range 2-24), using a standard regimen for most and combined radiotherapy for six. Twenty-two patients (51.2%) were considered as responders. Silent tumor at diagnosis was associated with a poor response. The median follow-up after the end of treatment was 16 months (0-72). Overall survival was significantly higher among responders (P = 0.002); however, ten patients relapsed 5 months (0-57) after the end of TMZ treatment, five in whom TMZ was reinitiated without success. DISCUSSION Patients in our series showed a 51.2% response rate to TMZ, with an improved survival among responders despite frequent relapses. Our study highlights the high variability and lack of standardization of treatment protocols.

Enhancement of islet engraftment and achievement of long-term islet allograft survival by Toll-like receptor 4 blockade.

Background Toll-like receptors are key players in sterile inflammation phenomena and can link the innate and adaptive immune systems by enhancing graft immunogenicity. They are also considered mediators of types 1 and 2 diabetes development. The aim of the present study was to assess the role of Toll-like receptor-4 (TLR4) in mediating the inflammatory and immune responses to pancreatic islets, thereby promoting inflammatory destruction and immune rejection of islet grafts. Methods Experiments were conducted in murine and human in vitro systems and in vivo murine islet transplant models, using species-specific anti-TLR4 monoclonal antibodies. In vitro, mixed lymphocyte-islet reaction experiments were performed to assess T-cell activation and proliferation. In vivo, both a syngeneic (B6-to-B6) marginal mass islet transplant model to assess the impact of TLR4 blockade on islet engraftment and an allogeneic (DBA1-to-B6) model were used. Results In vitro TLR4 blockade decreased lipopolysaccharide-mediated &bgr;-cell apoptosis and T-cell activation and proliferation against allogeneic islets. In vivo, TLR4 blockade resulted in significantly better syngeneic marginal mass islet engraftment and in indefinite allogeneic islet graft survival. Tolerance was not observed because donor-specific skin graft rechallenge in nonrejecting animals resulted in rejection of both skin and islets, but without accelerated rejection as compared to naive animals. Conclusion Taken together, our data indicate that TLR4 blockade leads to a significant improvement of syngeneic islet engraftment and of allogeneic islet graft survival. A mechanism of graft accommodation with concurrent inhibition of donor-specific immune memory is likely to be involved.

Islet of Langerhans isolation from pediatric and juvenile donor pancreases

Islet grafts isolated from young donors allow superior functional outcomes but are often associated with poor islet isolation yields. The objective of this study was to comparatively analyze the outcomes of islet isolation between young and older donors. We retrospectively analyzed 564 pancreas isolations performed at our institution. Isolation outcomes were compared between donors aged ≤20 years (n = 42, YD) and >20 years (n = 522, OD). Isolation procedure was identical in both groups. Prepurification percentage of embedded islets was higher in YD (44.3 ± 22.7% vs. 24.9 ± 20.9%, P < 0.001). This led to a lower recovery rate in YD (48% vs. 76%, P = 0.002) and hence lower postpurification IEQ/g pancreas in YD (2 412 ± 1 789 IEQ/g vs. 3 194 ± 1 892 IEQ/g, P = 0.01). Final yield was 180 982 ± 128 073 IEQ in YD and 244 167 ± 134 137 IEQ in OD, (P = 0.006). In vitro function was markedly, albeit nonsignificantly, higher in YD (SI: 4.5 ± 5.1 vs. 3.0 ± 5.7, P = 0.350). Proportion of transplanted preparations was similar in both groups, 38% (16/42) in YD vs. 43% (224/522) in OD, P = 0.628. In spite of isolation and purification difficulties, pancreases from young donors allowed similar islet transplantation rates as older donors. Efforts should be directed at improving islet extraction in these donors to realize their full potential for islet transplantation.

Quantification of islet loss and graft functionality during immune rejection by 3-tesla MRI in a rat model.

Background Because metabolic markers are not suitable for early diagnosis of islet graft dysfunction, magnetic resonance imaging (MRI) has been used to study islets that were labeled pretransplantation with superparamagnetic iron oxide nanoparticles. However, the relation between graft functionality assessed by glycemia, and MRI signal remains unclear. Methods We transplanted hyperglycemic rats intraportally with 2500 ferucarbotran-labeled syngeneic (n=10) or allogeneic (n=12) islet equivalents or normoglycemic rats with 5000 xenogeneic human islet equivalents. Images were acquired on a clinical 3-Tesla MRI scanner. Results When rejection occurred on days 4 and 8 in xenogeneic and allogeneic recipients, 60% (57–68) and 55% (46–73) of the initial signal remained compared to 93% (71–104) and 82% (59–90) in syngeneic controls (P=0.006 and 0.03). With a cutoff value of 84% on day 4 for the diagnosis of allogeneic rejection, sensitivity of 91% and specificity of 70% were obtained. Based on MRI signal on day 4, treatment with antilymphocytic serum from day 4 allowed graft rescue in 75% of recipients. Conclusions In this model, MRI of pretransplantation superparamagnetic iron oxide nanoparticle–labeled islet grafts allows timely diagnosis of immune rejection.