Sandrine Demuylder-Mischler

Clinical Magnetic Resonance Imaging of Pancreatic Islet Grafts After Iron Nanoparticle Labeling

There is a crucial need for noninvasive assessment tools after cell transplantation. This study investigates whether a magnetic resonance imaging (MRI) strategy could be clinically applied to islet transplantation. The purest fractions of seven human islet preparations were labeled with superparamagnetic iron oxide particles (SPIO, 280 μg/mL) and transplanted into four patients with type 1 diabetes. MRI studies (T2*) were performed prior to and at various time points after transplantation. Viability and in vitro and in vivo functions of labeled islets were similar to those of control islets. All patients could stop insulin after transplantation. The first patient had diffuse hypointense images on her baseline liver MRI, typical for spontaneous high iron content, and transplant‐related modifications could not be observed. The other three patients had normal intensity on pretransplant images, and iron‐loaded islets could be identified after transplantation as hypointense spots within the liver. In one of them, i.v. iron therapy prevented subsequent visualization of the spots because of diffuse hypointense liver background. Altogether, this study demonstrates the feasibility and safety of MRI‐based islet graft monitoring in clinical practice. Iron overload (spontaneous or induced) represents the major obstacle to the technique.

Influence of donor age on islet isolation and transplantation outcome

BACKGROUND It has been suggested that the age of human organ donors might influence islet isolation and transplantation outcome in a negative way due to a decrease of in vivo function in islets isolated from older donors. METHODS We retrospectively analyzed 332 islet isolations according to donor age. We determined isolation outcome by islet yields, transplantation rates, and [beta]-cell function in vitro. Transplanted patients were divided into two groups depending on donor age (n=25 and n=31 patients for <=45- and >45-year-old donors, respectively). We assessed islet graft function by C-peptide/glucose ratio, [beta] score, secretory units of islets in transplantation index, and insulin independence rate at 1, 6, and 12 months after transplantation. RESULTS There was no difference in islet yields between the two groups (251,900+/-14,100 and 244,600+/-8400 islet equivalent for <=45- and >45-year-old donors, respectively). Transplantation rates and stimulation indices were similar in both groups as well. All islet graft function parameters were significantly higher at 1-month follow-up in patients who had received islets from younger donors. At 6-month follow-up after second or third injection and at 12-month follow-up, secretory units of islets in transplantation indices and C-peptide/glucose ratios were significantly higher in patients with donors aged 45 years or younger. CONCLUSIONS These data suggest that, despite similar outcomes of the isolation procedure, islet graft function is significantly influenced by donor age. These results may have important consequences in the definition of pancreas allocation criteria.

Islet Autotransplantation After Extended Pancreatectomy for Focal Benign Disease of the Pancreas

Background. Extended pancreatectomy is associated with the risk of surgical diabetes. Islet autotransplantation is successful in the prevention of diabetes after pancreas resection for chronic pancreatitis (CP), with insulin independence rates of 50% at 1 year. The aim of the present study is to demonstrate the safety and efficiency of islet autotransplantation after extended left pancreatectomy for benign disease. Methods. Between 1992 and 2009, 25 patients underwent extended pancreatectomy and islet autotransplantation for benign disease. Of these, 15 patients were operated for focal lesions located at the neck of the pancreas (14 benign tumors and 1 traumatic pancreatic section), the remainder being CP cases. After unequivocal diagnosis of benignity, the rest of the pancreas was processed and infused into the portal vein. Metabolic results were analyzed and isolation results were compared with those obtained from patients with CP or donors with brain death (DBD). Results. There was no mortality and a low morbidity (Streptococcus mitis bacteremia in 1 patient), no portal thrombosis or pancreatic fistula occurred. Median follow-up was 90 months. Actuarial patient survival was 100% at 10 years. Actuarial insulin independence was 94% at 10 years. All patients had positive basal and stimulated C-peptide levels and normal HbA1c. Mean islet yields were 5455 IEQ/gram vs. 1457 in CP (P=0.001) and 3738 in DBD (P=0.003). Conclusions. Islet autotransplantation after extensive pancreatic resection for benign disease is a safe and successful procedure. Islet yields after isolation, which are equivalent to the live donor situation, are significantly better than those from DBD donors.

Low risk of anti-human leukocyte antigen antibody sensitization after combined kidney and islet 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.

Detection of insulin mRNA in the peripheral blood after human islet transplantion predicts deterioration of metabolic control

Recent updates of the Edmonton trial have shown that insulin independence is progressively lost in approximately 90% of islet transplant recipients over the first 5 years. Early prediction of islet graft injury could prompt the implementation of strategies attempting to salvage the transplanted islets. We hypothesize that islet damage is associated with the release and detection of insulin mRNA in the circulating blood. Whole blood samples were prospectively taken from 19 patients with type 1 diabetes receiving 31 islet transplants, immediately prior to transplantation and at regular time‐points thereafter. After RNA extraction, levels of insulin mRNA were determined by quantitative reverse tran‐scriptase‐polymerase chain reaction. All patients exhibited a primary peak of insulin mRNA immediately after transplantation, without correlation of duration and amplitude with graft size or outcome. Twenty‐five subsequent peaks were observed during the follow‐up of 17 transplantations. Fourteen secondary peaks (56%) were closely followed by events related to islet graft function. Duration and amplitude of peaks were higher when they heralded occurrence of an adverse event. Peaks of insulin mRNA can be detected and are often associated with alterations of islet graft function. These data suggest that insulin mRNA detection in the peripheral blood is a promising method for the prediction of islet graft damage.

Impairment of renal function after islet transplant alone or islet-after-kidney transplantation using a sirolimus/tacrolimus-based immunosuppressive regimen

The immunosuppressive (IS) regimen based on sirolimus/low‐dose tacrolimus is considered a major determinant of success of the Edmonton protocol. This regimen is generally considered safe or even protective for the kidney. Herein, we analyzed the impact of the sirolimus/low‐dose tacrolimus combination on kidney function. The medical charts of islet transplant recipients with at least 6 months follow up were reviewed. There were five islet‐after‐kidney and five islet transplantation alone patients. Serum creatinin, albuminuria, metabolic control markers and graft function were analyzed. Impairment of kidney function was observed in six of 10 patients. Neither metabolic markers nor IS drugs levels were significantly associated with the decrease of kidney function. Although a specific etiology was not identified, some subsets of patients presented a higher risk for decline of kidney function. Low creatinin clearance, albuminuria and long‐established kidney graft were associated with poorer outcome.

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.

Comparative Impact on Islet Isolation and Transplant Outcome of the Preservation Solutions Institut Georges Lopez-1, University of Wisconsin, and Celsior

Background. Institut Georges Lopez-1 (IGL-1) is a preservation solution similar to University of Wisconsin (UW) with reversed Na/K contents. In this study, we assessed the impact of IGL-1, UW, and Celsior (CS) solutions on islet isolation and transplant outcome. Methods. We retrospectively analyzed 376 islet isolations from pancreases flushed and transported with IGL-1 (n=95), UW (n=204), or CS (n=77). We determined isolation outcome and &bgr;-cell function in vitro. Transplanted patients were divided into three groups depending on preservation solution of pancreas, and islet graft function was assessed by decrease in daily insulin needs, C-peptide/glucose ratios, &bgr;-scores, and transplant estimated function at 1- and 6-month follow-up. Results. IGL-1, UW, and CS groups were similar according to donor age, body mass index, and pancreas weight. There was no difference in islet yields between the three groups. Success rates, transplant rates, &bgr;-cell secretory function, and viability were similar for all three groups. We observed no difference in decreased insulin needs, C-peptide glucose ratios, &bgr;-scores, and transplant estimated function at 1- and 6-month follow-up between IGL-1, UW, and CS groups. Conclusions. Our study shows that IGL-1 is equivalent to UW or CS solutions for pancreas perfusion and cold storage before islet isolation and transplantation.

Recurrence of type 1 diabetes after simultaneous pancreas-kidney transplantation in the absence of GAD and IA-2 autoantibodies

We report herein the patterns of type 1 diabetes recurrence in a simultaneous pancreas–kidney transplant (SPK) recipient, in the absence of rejection. A 38‐year‐old female underwent SPK for end‐stage nephropathy secondary to type 1 diabetes. Fasting blood glucose, HbA1c, fructosamine, C‐peptide and autoantibodies (GAD‐65, IA‐2) were monitored throughout follow‐up. At 3.5 years post‐SPK, HbA1c and fructosamine increased sharply, indicating loss of perfect metabolic control, despite C‐peptide levels in the normal‐high range. Exogenous insulin was restarted 4 months later. C‐peptide levels abruptly fell and became undetectable at 5.5 years. Autoantibody levels, which were undetectable at the time of SPK, never converted to positivity. Pancreas retranspantation was performed at 6 years. The failed pancreas graft had a normal macroscopic appearance. On histology, there were no signs of cellular or humoral rejection in the kidney or pancreas. A selective peri‐islet lymphocytic infiltrate was observed, together with near‐total destruction of β cells. At 2.5 years post retransplantation, pancreatic graft function is perfect. This observation indicates unequivocally that pancreas graft can be lost to recurrence of type 1 diabetes in the absence of rejection. GAD‐65 and IA‐2 autoantibodies are not reliable markers of autoimmunity recurrence.

Pancreas retransplantation: a second chance for diabetic patients?

BACKGROUND If pancreas transplantation is a validated alternative for type 1 diabetic patients with end-stage renal disease, the management of patients who have lost their primary graft is poorly defined. This study aims at evaluating pancreas retransplantation outcome. METHODS Between 1976 and 2008, 569 pancreas transplantations were performed in Lyon and Geneva, including 37 second transplantations. Second graft survival was compared with primary graft survival of the same patients and the whole population. Predictive factors of second graft survival were sought. Patient survival and impact on kidney graft function and survival were evaluated. RESULTS Second pancreas survival of the 17 patients transplanted from 1995 was close to primary graft survival of the whole population (71% vs. 79% at 1 year and 59% vs. 69% at 5 years; P=0.5075) and significantly better than their first pancreas survival (71% vs. 29% at 1 year and 59% vs. 7% at 5 years; P=0.0008) regardless of the cause of first pancreas loss. The same results were observed with all 37 retransplantations. Survival of second simultaneous pancreas and kidney transplantations was better than survival of second pancreas after kidney. Patient survival was excellent (89% at 5 years). Pancreas retransplantation had no impact on kidney graft function and survival (100% at 5 years). CONCLUSION Pancreas retransplantation is a safe procedure with acceptable graft survival that should be proposed to diabetic patients who have lost their primary graft.Background If pancreas transplantation is a validated alternative for type 1 diabetic patients with end-stage renal disease, the management of patients who have lost their primary graft is poorly defined. This study aims at evaluating pancreas retransplantation outcome. Methods Between 1976 and 2008, 569 pancreas transplantations were performed in Lyon and Geneva, including 37 second transplantations. Second graft survival was compared with primary graft survival of the same patients and the whole population. Predictive factors of second graft survival were sought. Patient survival and impact on kidney graft function and survival were evaluated. Results Second pancreas survival of the 17 patients transplanted from 1995 was close to primary graft survival of the whole population (71% vs. 79% at 1 year and 59% vs. 69% at 5 years; P=0.5075) and significantly better than their first pancreas survival (71% vs. 29% at 1 year and 59% vs. 7% at 5 years; P=0.0008) regardless of the cause of first pancreas loss. The same results were observed with all 37 retransplantations. Survival of second simultaneous pancreas and kidney transplantations was better than survival of second pancreas after kidney. Patient survival was excellent (89% at 5 years). Pancreas retransplantation had no impact on kidney graft function and survival (100% at 5 years). Conclusion Pancreas retransplantation is a safe procedure with acceptable graft survival that should be proposed to diabetic patients who have lost their primary graft.