Tatiana Froud

Islet Transplantation in Type 1 Diabetes Mellitus Using Cultured Islets and Steroid-Free Immunosuppression: Miami Experience

Following the success obtained with transplantation of fresh human islets under steroid‐free immunosuppression, this trial evaluated the transplantation of islets that had undergone a period of in vitro culture and the potential of tumor necrosis factor (TNF‐α) blockade to improve islet engraftment. Subjects included 16 patients with type 1 diabetes mellitus (T1DM); half were randomly assigned to receive Infliximab immediately preceding initial infusion. Immunosuppression consisted of daclizumab induction and sirolimus/tacrolimus maintenance. Out of 16 subjects 14 achieved insulin independence with one or two islet infusions; adverse events precluded completion in two. Without supplemental infusions, 11/14 (79%) subjects were insulin independent at 1 year, 6/14 (43%) at 18 months; these same subjects remain insulin independent at 33 ± 6 months. While on immunosuppression, all patients maintained graft function. Out of 14 patients, 8 suffered chronic partial graft loss, likely immunological in nature, 5 of these received supplemental infusions. Currently, 11 subjects remain on immunosuppression, 8 (73%) are insulin independent, two with supplemental infusions. Insulin independent subjects demonstrated normalization of HbA1c, fructosamine and Mean Amplitude of Glycemic Excursions (MAGE) values. No clinical benefit of infliximab was identified. These results demonstrate that transplantation of cultured human islet allografts results in reproducible insulin independence in all subjects under this immunosuppressive regimen, comparable to that of freshly transplanted islets (Edmonton protocol).

Percutaneous irreversible electroporation for downstaging and control of unresectable pancreatic adenocarcinoma.

PURPOSE Treatment of unresectable locally advanced pancreatic cancer (LAPC) usually includes chemotherapy and/or radiation therapy in an attempt to downstage these tumors to the extent of resectability, but outcomes remain poor. Irreversible electroporation (IRE) is an ablative modality that may be useful in this population. The aim of this study was to evaluate the safety of percutaneous IRE in patients with pancreatic adenocarcinoma. MATERIALS AND METHODS IRE was performed in patients with pancreatic cancer whose tumors remained unresectable after, or who were intolerant of, standard therapy. The procedures were all done percutaneously under general anesthesia. Patients were then followed for adverse events, tumor response, and survival. RESULTS Fifteen IRE procedures were performed in 14 patients (one was treated twice). Three patients had metastatic disease and 11 had LAPC. All patients had received chemotherapy previously, and 11 had received radiation. The median tumor size was 3.3 cm (range, 2.5-7 cm). Immediate and 24-hour postprocedural scans demonstrated patent vasculature in the treatment zone in all patients. Two patients underwent surgery 4 and 5 months after IRE, respectively. Both had margin-negative resections, and one had a pathologic complete response; both remain disease-free after 11 and 14 months, respectively. Complications included spontaneous pneumothorax during anesthesia (n = 1) and pancreatitis (n = 1), and both patients recovered completely. There were no deaths directly related to the procedure. All three patients with metastatic disease at IRE died from progression of their disease. CONCLUSIONS Percutaneous IRE for pancreatic adenocarcinoma is feasible and safe. A prospective trial is being planned.

Immunosuppression and procedure-related complications in 26 patients with type 1 diabetes mellitus receiving allogeneic islet cell transplantation

Background. The success of sirolimus and low-dose tacrolimus in islet cell transplantation has influenced many transplant centers to utilize this novel regimen. The long-term safety and tolerability of this steroid-free immunosuppressive protocol for allogeneic islet transplantation has yet to be determined. Methods. We transplanted 26 adult patients with long standing type 1 diabetes mellitus between April 2000 and June 2004. Immunosuppression consisted of induction with daclizumab and maintenance therapy with tacrolimus and sirolimus. Adverse events (AEs) in patients were followed and graded using the Common Terminology Criteria for Adverse Events, version 3.0 (National Cancer Institute). Results. To date, the majority of patients were able to remain on the immunosuppression combination for up to 22±11 months. Four patients were successfully converted to Mycophenolate Mofetil due to tacrolimus-related toxicity. Withdrawal from immunosuppression was decided in four patients due to hypereosinophilic syndrome, parvovirus infection, aspiration pneumonia, and severe depression, respectively. Six patients required filgrastim therapy for neutropenia. Transient elevation of liver enzymes was observed in most patients early after islet infusion. Increased LDL in 20 patients required medical treatment. Conclusion. There was a varying range of AEs, most of them mild and self-limiting; however, some required urgent medical attention. The majority of patients were able to tolerate and remain on this effective regimen. To date, no deaths, cytomegalovirus disease, graft-versus-host disease, or posttransplant lymphoproliferative disease has been observed.

Long-term insulin independence and improvement in insulin secretion after supplemental islet infusion under exenatide and etanercept.

Background. Progressive graft dysfunction (GDF) and loss of insulin independence (II) have been invariably observed in islet transplant recipients under the “Edmonton protocol.” To reestablish II, we performed supplemental islet infusions (SI) in recipients of allogeneic islet transplant alone, displaying GDF. To improve the engraftment and long-term graft function of SI, exenatide (EXN) and etanercept treatment at islet infusion, and long-term EXN treatment were tested in a non-randomized pilot clinical trial. Methods. Patients with GDF received SI under Edmonton-like immunosuppression with daclizumab induction, either without interventions (SI-control; n=5) or with EXN and etanercept treatment (SI-EXN; n=4). Clinical and metabolic profiles were assessed during 18-month follow-up. Results. Long-term II (18 months) was observed in 100% of SI-EXN and in 20% of SI-control (P=0.04). SI-EXN subjects demonstrated restoration of function better than that seen after initial islet infusions. Comparison of SI-EXN and SI-control groups demonstrated better responses in SI-EXN subjects at 3 months post-SI. During the 18 months of follow-up, function was sustained in the SI-EXN subjects better than in SI-controls. Acute effects of EXN during mixed meal tolerance test and intravenous glucose tolerance test results in improved first and second phase insulin release in response to intravenous glucose tolerance test and suppressed postprandial hyperglucagonemia after mixed meal tolerance test. Conclusion. These results suggest that the combination of EXN and etanercept improve engraftment and long-term islet survival and function in subjects undergoing SI. This data, however, must be interpreted with some caution because of small sample size, lack of randomization, and sequential comparison with historical controls.

The bag method for islet cell infusion.

As islet cell transplantation gains increasing interest following results published by the Edmonton group, results that have been successfully reproduced by several centers nationwide and abroad, the need of guidelines to standardize the procedure becomes highly important. We detail the key steps of the infusion procedure utilizing a closed gravity fed bag system utilized at our institution since 1990, which consists of a 600-ml transfer bag and a 150-ml rinse bag connected via sterile tubing. The use of gravity allows for a control rate of infusion as well as providing a safety mechanism through natural reduction of flow that parallels any increase in portal pressure, therefore allowing the operator to prevent precipitous pressure rises. Reports on significant rise in portal pressures during islet cell infusion as well as portal vein thrombosis have been published. Infusion at these centers was carried out using a syringe method. Using our technique, portal vein thrombosis (partial or complete) was not detected in any of the infusions performed at our institution. This method may be of assistance to minimize some of the observed complications associated with islet transplant procedures and has now been adapted by most centers performing clinical islet transplantation.

The Use of Exenatide in Islet Transplant Recipients with Chronic Allograft Dysfunction: Safety, Efficacy and Metabolic Effects

Background. A current limitation of islet transplantation is reduced long-term graft function. The glucagon-like peptide-1 receptor agonist, exenatide (Byetta, Amylin Pharmaceuticals, CA) has properties that could improve existing islet function, prevent further loss of islet mass and possibly even stimulate islet regeneration. Methods. This prospective study evaluated the safety, efficacy, and metabolic effects of exenatide in subjects with type 1 diabetes mellitus and islet allograft dysfunction requiring exogenous insulin. Results. Sixteen subjects commenced exenatide, 12 continue (follow-up 214±57 days; range 108–287), four (25%) discontinued medication because of side effects. At 6 months, exogenous insulin was significantly reduced with stable glycemic control (0.15±0.02 vs. 0.11±0.025 U/kg per day; P<0.0001); three subjects discontinued insulin from 4, 5, and 9 U/day, respectively, two sustained insulin independence with A1c reduction below graft dysfunction criteria. Postprandial capillary blood glucose was significantly decreased (129.4±3.8 vs. 118.7±4.6 mg/dL; P<0.001), C-peptide and C-peptide-to-glucose ratio increased significantly by 5th and 6th months of treatment (ratio, 1.09±0.15 vs. 1.52±0.18; P<0.05). Weight loss more than 3 kg occurred in 8 of 12 (67%) subjects. Stimulation testing demonstrated improved glucose disposal and C-peptide secretion (glucose area under the curve 52,332±3,219 vs. 42,072±1,965; P=0.002 mg·min−1·dL−1, mixed meal stimulation index 0.50±0.06 vs. 0.66±0.09; P=0.03 pmol·mL−1), with marked suppression of glucagon secretion and progressive increase in amylin secretion. Side effects were more frequent and severe compared with published reports in type 2 diabetes, tolerated doses were lower. Conclusions. Exenatide was tolerated in this patient population after appropriate dose titration and there appeared to be gradual but sustained positive effects on glycemic control and islet graft function.

Combined Treatment of Intrapancreatic Autologous Bone Marrow Stem Cells and Hyperbaric Oxygen in Type 2 Diabetes Mellitus

The objective of this study was to determine whether the combination therapy of intrapancreatic autologous stem cell infusion (ASC) and hyperbaric oxygen treatment (HBO) before and after ASC can improve islet function and metabolic control in patients with type 2 diabetes mellitus (T2DM). This prospective phase 1 study enrolled 25 patients with T2DM who received a combination therapy of intrapancreatic ASC and periinfusion HBO between March 2004 and October 2006 at Stem Cells Argentina Medical Center Buenos Aires, Argentina. Clinical variables (body mass index, oral hypoglycemic drugs, insulin requirement) and metabolic variables (fasting plasma glucose, C-peptide, HbA1c, and calculation of C-peptide/glucose ratio) were assessed over quartile periods starting at baseline and up to 1 year follow-up after intervention. Means were calculated in each quartile period and compared to baseline. Seventeen male and eight female patients were enrolled. Baseline variables expressed as means ± SEs were: age 55 ± 2.14 years, diabetes duration 13.2 ± 1.62 years, insulin dose 34.8 ± 2.96 U/day, and BMI 27.11 ± 0.51. All metabolic variables showed significant improvement when comparing baseline to 12 months follow-up, respectively: fasting glucose 205.6 ± 5.9 versus 105.2 ± 14.2 mg/dl, HbA1c 8.8 ± 0.2 versus 6.0 ± 0.4%, fasting C-peptide 1.5 ± 0.2 versus 3.3 ± 0.3 ng/ml, C-peptide/glucose ratio 0.7 ± 0.2 versus 3.5 ± 0.3, and insulin requirements 34.8 ± 2.9 versus 2.5 ± 6.7 U/day. BMI remained constant over the 1-year follow-up. Combined therapy of intrapancreatic ASC infusion and HBO can improve metabolic control and reduce insulin requirements in patients with T2DM. Further randomized controlled clinical trials will be required to confirm these findings.

Pancreatic islet transplantation: the radiographic approach.

Background. Successful pancreatic islet transplantation (PIT) has resulted in several transplant centers wanting to start PIT programs. PIT remains experimental and must be performed safely for its continued use. We describe the radiographic techniques used at our center and their results. Methods. Between January 17, 2002, and December 16, 2002, 17 percutaneous transhepatic PITs were performed by two interventional radiologists. Ultrasound localization of and guidance to the portal vein (PV) were used. Portosplenography confirmed the position of the PV islet infusion catheter, and PV pressure was documented before, during, and at the completion of PIT. To prevent PV thrombosis, heparin (17.5 U/kg) through the PV infusion catheter and subcutaneous enoxaparin (Lovenox, Aventis Pharmaceuticals, Parsippany, NJ) were administered after PIT. At the completion of PIT, thrombin‐saturated Gelfoam (Johnson and Johnson, Summerville, NJ) was embolized into the hepatic parenchymal tract. Results. Percutaneous PV access was achieved in all cases (median number of seeker needle passes=2, range: 1‐6), and PIT was performed. In no case was any extrahepatic organ punctured, and sustained PV hypertension was not seen. No patient required transfusion, and it was documented by Doppler ultrasonography that PV thrombosis did not result from PIT. In addition, intraparenchymal and intraabdominal bleeding did not complicate any PIT; 71% and 59% of the patients experienced moderate posttransplant abdominal pain and nausea, respectively. All patients demonstrated a self‐limited, asymptomatic posttransplant transaminitis. Conclusions. We believe that PIT should be performed by a small number of experienced interventional radiologists using ultrasound guidance and posttransplant embolization of the hepatic parenchymal tract.

Simple Measures to Monitor β-Cell Mass and Assess Islet Graft Dysfunction

The aim of this study was to develop a simple test for the assessment of islet graft dysfunction based on measures involving fasting C‐peptide. Calculations were made to account for the dependence of C‐peptide secretion on glucose concentration (C‐peptide/glucose ratio [CP/G]) and adjusted for renal function by calculating the C‐peptide/glucose‐creatinine ratio (CP/GCr). Values from 22 recipients were analyzed at different times post‐last islet infusion. Receiver operating characteristic curves were used to determine which of these measures best predicts high 90‐minute glucose (90 min‐Glc; >10 mmol/L) after a Mixed Meal Tolerance Test (MMTT). In this initial analysis, CP/G was found to be superior predicting high 90 min‐Glc with a larger area under the ROC curve than C‐peptide (p = 0.01) and CP/GCr (p = 0.06). We then correlated C‐peptide and CP/G with islet equivalents‐IEQ/kg infused, 90 min‐Glc after MMTT and clinical outcome (β‐score). C‐peptide and CP/G in the first 3 months post‐last islet infusion correlated with IEQ/kg infused. CP/G correlated with 90 min‐Glc and β‐score. C‐peptide and CP/G are good indicators of islet mass transplanted. CP/G is more indicative of graft dysfunction and clinical outcome than C‐peptide alone. The ease of calculation and the good correlation with other tests makes this ratio a practical tool when monitoring and managing islet transplant recipients.

Improved Metabolic Control and Quality of Life in Seven Patients With Type 1 Diabetes Following Islet After Kidney Transplantation

Background. The beneficial effects of glycemic control on both survival and function of transplanted kidneys in patients with type 1 diabetes mellitus (T1DM) and end-stage renal disease (ESRD) have been recognized. Methods. Herein, we present the clinical outcome of a single-center pilot trial of islet after kidney (IAK) transplantation in seven patients with T1DM. The immunosuppression protocol for the kidney graft was converted to sirolimus+tacrolimus regimen 6 months before islet transplantation to exclude negative effects on kidney graft function. Primary endpoint was achievement of insulin independence after transplantation. Clinical outcome, metabolic control, severe hypoglycemia, kidney function, Quality of Life (QOL) psychometric measures, and adverse events were monitored. Results. Seven patients showed graft function with improved metabolic control (A1c, fasting glycemia, and metabolic tests) after IAK (14,779±3,800 IEQ/kg). One-year insulin independence was 30% with persistent graft function in 86% (C-peptide-positive). A1c reduction was 1.95±0.31% from baseline (P<0.0001). No episodes of severe hypoglycemia were observed, even after resuming insulin. The direct consequence of these benefits was a significant improvement in diabetes QOL. Adverse events included procedure-related pleural effusion (n=2), cholecystitis (n=1), and additional immunosuppression-related, all resolved without sequelae. Kidney function (by estimated glomerular filtration rate) remained stable during follow-up in six of seven patients. Conclusions. Islet transplantation represents a feasible therapeutic option for patients with T1DM bearing a stable kidney allograft. Insulin independence at 1 year is lower than what reported in islet transplant alone. Nevertheless, clear benefits in terms of optimal metabolic control and absence of severe hypoglycemia are invariably present.