Impact of GAD65 and IA2 autoantibodies on islet allograft survival.

Introduction: Islet transplantation (ITx) shows promise in treating T1D, but the role of islet autoantibodies on graft survival has not been clearly elucidated. We aimed to analyze the effect of GAD65 and IA2 autoantibody status on graft survival and attainment of insulin independence in subjects with T1D who underwent ITx. Method: We conducted a retrospective cohort study on 47 ITx recipients from 2000 to 2018. Islet infusion was performed via intrahepatic portal (n=44) or onto the omentum via laparoscopic approach (n=3). Immunosuppression involved anti-IL2 receptor antibody, anti-TNF, and dual combinations of sirolimus, tacrolimus, or mycophenolate mofetil (Edmonton-like) in 38 subjects (80.9%). T-cell depletion induction with Edmonton-like maintenance was used in 9 subjects (19%). GAD65 and IA2 autoantibodies were assessed pre-transplant and post-transplant (monthly) until graft failure, and categorized as persistently negative, persistently positive, or seroconverters. Graft survival was analyzed using U-Mann-Whitney test, and Quade's nonparametric ANCOVA adjusted for confounders. Kaplan-Meier and Log-Rank tests were employed to analyze attainment of insulin independence. P value <0.05 indicated statistical significance. Results: ITx recipients with persistent autoantibody negativity (n = 21) showed longer graft function (98 [61 - 182] months) than those with persistent autoantibody positivity (n = 18; 38 [13 - 163] months), even after adjusting for immunosuppressive induction protocol (P = 0.027). Seroconverters (n=8) had a median graft survival time of 73 (7.7 - 167) months, which did not significantly differ from the other 2 groups. Subjects with persistently single antibody positivity to GAD65 (n = 8) had shorter graft survival compared to negative islet autoantibody (GAD65/IA2) subjects (n = 21; P = 0.016). Time of graft survival did not differ in subjects with single antibody positivity to IA2. The proportion of insulin independence attainment was similar irrespective of autoantibody status. Conclusion: The persistence of islet autoantibodies, as markers of islet autoimmunity, may represent an underappreciated contributing factor to the failure of transplanted ß cells. Whether induction with T-cell depletion may lead to improved graft survival, independent of islet autoantibody status, could not be evaluated in our cohort. Larger prospective studies are needed to further address the role of islet autoantibody status on islet graft survival.

Comparison of Glycemic Control Between In-Person and Virtual Diabetes Consults in Hospitalized Patients With Diabetes.

BACKGROUND: There is limited evidence that the diabetes in-person consult in hospitalized patients can be replaced by a virtual consult. During COVID-19 pandemic, the diabetes in-person consult service at the University of Miami and Miami Veterans Affairs Healthcare System transitioned to a virtual model. The aim of this study was to assess the impact of telemedicine on glycemic control after this transition. METHODS: We retrospectively analyzed glucose metrics from in-person consults (In-person) during January 16 to March 14, 2020 and virtual consults during March 15 to May 14, 2020. Data from virtual consults were analyzed by separating patients infected with COVID-19, who were seen only virtually (Virtual-COVID-19-Pos), and patients who were not infected (Virtual-COVID-19-Neg), or by combining the two groups (Virtual-All). RESULTS: Patient-day-weighted blood glucose was not significantly different between In-person, Virtual-All, and Virtual-COVID-19-Neg, but Virtual-COVID-19-Pos had significantly higher mean ± SD blood glucose (mg/dL) compared with others (206.7 ± 49.6 In-person, 214.6 ± 56.2 Virtual-All, 206.5 ± 57.2 Virtual-COVID-19-Neg, 229.7 ± 51.6 Virtual-COVID-19-Pos; P = .015). A significantly less percentage of patients in this group also achieved a mean ± SD glucose target of 140 to 180 mg/dL (23.8 ± 22.5 In-person, 21.5 ± 20.5 Virtual-All, 25.3 ± 20.8 Virtual-COVID-19-Neg, and 14.4±18.1 Virtual-COVID-19-Pos, P = .024), but there was no significant difference between In-person, Virtual-All, and Virtual-COVID-19-Neg. The occurrence of hypoglycemia was not significantly different among groups. CONCLUSIONS: In-person and virtual consults delivered by a diabetes team at an academic institution were not associated with significant differences in glycemic control. These real-world data suggest that telemedicine could be used for in-patient diabetes management, although additional studies are needed to better assess clinical outcomes and safety.

HLA-B Matching Prolongs Allograft Survival in Islet Cell Transplantation.

Islet cell transplantation (ITx) is an effective therapeutic approach for selected patients with type 1 diabetes with hypoglycemia unawareness and severe hypoglycemia events. In organ transplantation, human leukocyte antigen (HLA) mismatching between donor and recipient negatively impacts transplant outcomes. We aimed to determine whether HLA matching has an impact on islet allograft survival. Forty-eight patients were followed up after islet transplantation at our institution from 2000 to 2020 in a retrospective cohort. Patients underwent intrahepatic ITx or laparoscopic omental approach. Immunosuppression was dependent upon the protocol. We analyzed HLA data restricted to A, B, and DR loci on allograft survival using survival and subsequent multivariable analyses. Patients were aged 42.8 ± 8.4 years, and 64.3% were female. Diabetes duration was 28.6 ± 11.6 years. Patients matching all three HLA loci presented longer graft survival (P = 0.030). Patients with ≥1 HLA-B matching had longer graft survival compared with zero matching (P = 0.025). The number of HLA-B matching was positively associated with time of graft survival (Spearman's rho = 0.590; P = 0.034). Analyses adjusted for confounders showed that ≥1 matching for HLA-B decreased the risk of allograft failure (P = 0.009). Our data suggest that HLA-B matching between recipients and donors improved islet allograft survival. Matching all three HLA loci (A, B, and DR) was also associated with prolonged islet allograft survival. Prospective studies and a larger sample size are warranted to validate our findings.

Predictive Value of C-Peptide Measures for Clinical Outcomes of ß-Cell Replacement Therapy in Type 1 Diabetes: Report From the Collaborative Islet Transplant Registry (CITR).

OBJECTIVE: To determine C-peptide measures and levels associated with positive glycemic control outcomes following islet transplant (ITx) in type 1 diabetes. RESEARCH DESIGN AND METHODS: We evaluated Collaborative Islet Transplant Registry (CITR) islet-alone recipients with pretransplant C-peptide <0.1 nmol/L and mean follow-up of 4.6 ± 1.1 years (n = 677). Receiver operating characteristic area under the curve (ROC-AUC) was used to evaluate the predictive value of fasting and stimulated glucose and C-peptide measures for seven primary outcomes: 1) absence of severe hypoglycemic events (ASHEs); 2) HbA1c <7.0%; 3) HbA1c <7.0% and ASHEs; 4) HbA1c ≤6.5%; 5) HbA1c ≤6.5% and ASHEs; 6) insulin independence; and 7) ASHEs, HbA1c ≤6.5%, and insulin independence (the optimal outcome). Measures with the highest ROC-AUC were selected for determination of optimal cut points. RESULTS: Fasting C-peptide was highly predictive for ASHE (ROC-AUC 0.906; optimal cut point 0.070 nmol/L) and the optimal outcome (ROC-AUC 0.845; optimal cut point 0.33 nmol/L). Mixed-meal tolerance test (MMTT)-stimulated C-peptide-to-glucose ratio (CPGR) outperformed both fasting and stimulated C-peptide for all outcomes except ASHE. The optimal cut point for the optimal outcome was 0.12 nmol/mmol for MMTT-stimulated CPGR and 0.97 nmol/L for MMTT-stimulated C-peptide. CONCLUSIONS: Fasting C-peptide reliably predicts ITx primary outcomes. MMTT-stimulated CPGR provides marginally better prediction for composite ITx outcomes, including insulin independence. In the absence of an MMTT, a fasting C-peptide ≥0.33 nmol/L is a reassuring measure of optimal islet graft function. C-peptide targets represent excellent and easily determinable means to predict glycemic control outcomes after ITx and should be considered as potential goals of ß-cell replacement.

Increase Access, Reduce Disparities: Recommendations for Modifying Medicaid CGM Coverage Eligibility Criteria.

Numerous studies have demonstrated the clinical value of continuous glucose monitoring (CGM) in type 1 diabetes (T1D) and type 2 diabetes (T2D) populations. However, the eligibility criteria for CGM coverage required by the Centers for Medicare & Medicaid Services (CMS) ignore the conclusive evidence that supports CGM use in various diabetes populations that are currently deemed ineligible. In an earlier article, we discussed the limitations and inconsistencies of the agency's CGM eligibility criteria relative to current scientific evidence and proposed practice solutions to address this issue and improve the safety and care of Medicare beneficiaries with diabetes. Although Medicaid is administered through CMS, there is no consistent Medicaid policy for CGM coverage in the United States. This article presents a rationale for modifying and standardizing Medicaid CGM coverage eligibility across the United States.

Oral Glucose Tolerance Test Measures of First-phase Insulin Response and Their Predictive Ability for Type 1 Diabetes.

CONTEXT: Decreased first-phase insulin response (FPIR) during intravenous glucose tolerance testing (IVGTT) is an early indicator of ß-cell dysfunction and predictor of type 1 diabetes (T1D). OBJECTIVE: Assess whether oral glucose tolerance test (OGTT) measures could serve as FPIR alternatives in their ability to predict T1D in autoantibody positive (Aab+) subjects. DESIGN: OGTT and IVGTT were performed within 30 days of each other. Eleven OGTT variables were evaluated for (1) correlation with FPIR and (2) T1D prediction. SETTING: Type 1 Diabetes TrialNet "Oral Insulin for Prevention of Diabetes in Relatives at Risk for T1D" (TN-07) and Diabetes Prevention Trial-Type 1 Diabetes (DPT-1) studies clinical sites. PATIENTS: TN-07 (n = 292; age 9.4 ±â€…6.1 years) and DPT-1 (n = 194; age 15.1 ±â€…10.0 years) Aab + relatives of T1D individuals. MAIN OUTCOME MEASURES: (1) Correlation coefficients of OGTT measures with FPIR and (2) T1D prediction at 2 years using area under receiver operating characteristic (ROCAUC) curves. RESULTS: Index60 showed the strongest correlation in DPT-1 (r = -0.562) but was weaker in TN-07 (r = -0.378). C-peptide index consistently showed good correlation with FPIR across studies (TN-07, r = 0.583; DPT-1, r = 0.544; P < 0.0001). Index60 and C-peptide index had the highest ROCAUCs for T1D prediction (0.778 vs 0.717 in TN-07 and 0.763 vs 0.721 in DPT-1, respectively; P = NS), followed by FPIR (0.707 in TN-07; 0.628 in DPT-1). CONCLUSIONS: C-peptide index was the strongest measure to correlate with FPIR in both studies. Index60 and C-peptide index had the highest predictive accuracy for T1D and were comparable. OGTTs could be considered instead of IVGTTs for subject stratification in T1D prevention trials.

Prolonged Islet Allograft Function is Associated With Female Sex in Patients After Islet Transplantation.

BACKGROUND: Islet transplantation (ITx) has proved to be effective in preventing severe hypoglycemia and improving metabolic control in selected subjects with type 1 diabetes. Long-term graft function remains a challenge. Estrogens have been shown to protect ß cells from metabolic stresses and improve revascularization of transplanted human islets in the mouse. We aimed to evaluate the influence of sex in allograft survival of ITx recipients. METHODS: We analyzed a retrospective cohort of ITx recipients (n = 56) followed-up for up to 20 years. Allograft failure was defined as a stimulated C-peptide <0.3 ng/mL during a mixed-meal tolerance test. Subjects were divided into recipients of at least 1 female donor (group 1) and recipients of male donors only (group 2). RESULTS: Group 1 subjects (n = 25) were aged 41.5 ± 8.4 years and group 2 subjects (n = 22) 45.9 ± 7.3 years (P = 0.062). Female recipient frequency was 44.8% (n = 13) in group 1 and 55.2% (n = 16) in group 2 (P = 0.145). Group 2 developed graft failure earlier than group 1 (680 [286-1624] vs 1906 [756-3256] days, P = 0.038). We performed additional analyses on female recipients only from each group (group 1, n = 16; group 2, n = 20). Female recipients in group 1 exhibited prolonged allograft function compared with group 2, after adjustment for confounders (odds ratio, 28.6; 95% CI, 1.3-619.1; P < 0.05). CONCLUSION: Recipients of islets from at least 1 female donor exhibited prolonged graft survival compared with recipients of islets from exclusively male donors. In addition, female recipients exhibited prolonged survival compared with male recipients following ITx of at least 1 female donor.

IL-6 receptor blockade does not slow ß cell loss in new-onset type 1 diabetes.

BackgroundIL-6 receptor (IL-6R) signaling drives development of T cell populations important to type 1 diabetes pathogenesis. We evaluated whether blockade of IL-6R with monoclonal antibody tocilizumab would slow loss of residual ß cell function in newly diagnosed type 1 diabetes patients.MethodsWe conducted a multicenter, randomized, placebo-controlled, double-blind trial with tocilizumab in new-onset type 1 diabetes. Participants were screened within 100 days of diagnosis. Eligible participants were randomized 2:1 to receive 7 monthly doses of tocilizumab or placebo. The primary outcome was the change from screening in the mean AUC of C-peptide collected during the first 2 hours of a mixed meal tolerance test at week 52 in pediatric participants (ages 6-17 years).ResultsThere was no statistical difference in the primary outcome between tocilizumab and placebo. Immunophenotyping showed reductions in downstream signaling of the IL-6R in T cells but no changes in CD4 memory subsets, Th17 cells, Tregs, or CD4+ T effector cell resistance to Treg suppression. A DC subset decreased during therapy but regressed to baseline once therapy stopped. Tocilizumab was well tolerated.ConclusionTocilizumab reduced T cell IL-6R signaling but did not modulate CD4+ T cell phenotypes or slow loss of residual ß cell function in newly diagnosed individuals with type 1 diabetes.Trial RegistrationClinicalTrials.gov NCT02293837.FundingNIH National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and National Institute of Allergy and Infectious Diseases (NIAID) UM1AI109565, UL1TR000004 from NIH/National Center for Research Resources (NCRR) Clinical and Translational Science Award (CTSA), NIH/NIDDK P30DK036836, NIH/NIDDK U01DK103266, NIH/NIDDK U01DK103266, 1UL1TR000064 from NIH/NCRR CTSA, NIH/National Center for Advancing Translational Sciences (NCATS) UL1TR001878, UL1TR002537 from NIH/CTSA; National Health and Medical Research Council Practitioner Fellowship (APP1136735), NIH/NIDDK U01-DK085476, NIH/CTSA UL1-TR002494, Indiana Clinical and Translational Science Institute Award UL1TR002529, Vanderbilt Institute for Clinical and Translational Research UL1TR000445. NIH/NCATS UL1TR003142, NIH/CTSA program UL1-TR002494, Veteran Affairs Administration, and 1R01AI132774.

Dual-hormone artificial pancreas for management of type 1 diabetes: Recent progress and future directions.

Over the last few years, technological advances have led to tremendous improvement in the management of type 1 diabetes (T1D). Artificial pancreas systems have been shown to improve glucose control compared with conventional insulin pump therapy. However, clinically significant hypoglycemic and hyperglycemic episodes still occur with the artificial pancreas. Postprandial glucose excursions and exercise-induced hypoglycemia represent major hurdles in improving glucose control and glucose variability in many patients with T1D. In this regard, dual-hormone artificial pancreas systems delivering other hormones in addition to insulin (glucagon or amylin) may better reproduce the physiology of the endocrine pancreas and have been suggested as an alternative tool to overcome these limitations in clinical practice. In addition, novel ultra-rapid-acting insulin analogs with a more physiological time-action profile are currently under investigation for use in artificial pancreas devices, aiming to address the unmet need for further improvements in postprandial glucose control. This review article aims to discuss the current progress and future outlook in the development of novel ultra-rapid insulin analogs and dual-hormone closed-loop systems, which offer the next steps to fully closing the loop in the artificial pancreas.

The demise of islet allotransplantation in the United States: A call for an urgent regulatory update.

Islet allotransplantation in the United States (US) is facing an imminent demise. Despite nearly three decades of progress in the field, an archaic regulatory framework has stymied US clinical practice. Current regulations do not reflect the state-of-the-art in clinical or technical practices. In the US, islets are considered biologic drugs and "more than minimally manipulated" human cell and tissue products (HCT/Ps). In contrast, across the world, human islets are appropriately defined as "minimally manipulated tissue" and not regulated as a drug, which has led to islet allotransplantation (allo-ITx) becoming a standard-of-care procedure for selected patients with type 1 diabetes mellitus. This regulatory distinction impedes patient access to islets for transplantation in the US. As a result only 11 patients underwent allo-ITx in the US between 2016 and 2019, and all as investigational procedures in the settings of a clinical trials. Herein, we describe the current regulations pertaining to islet transplantation in the United States. We explore the progress which has been made in the field and demonstrate why the regulatory framework must be updated to both better reflect our current clinical practice and to deal with upcoming challenges. We propose specific updates to current regulations which are required for the renaissance of ethical, safe, effective, and affordable allo-ITx in the United States.

The Effect of Ethnicity in the Rate of Beta-Cell Functional Loss in the First 3 Years After Type 1 Diabetes Diagnosis.

OBJECTIVE: We set forth to compare ethnicities for metabolic and immunological characteristics at the clinical diagnosis of type 1 diabetes (T1D) and assess the effect of ethnicity on beta-cell functional loss within 3 years after clinical diagnosis. RESEARCH METHODS AND DESIGN: We studied participants in TrialNet New Onset Intervention Trials (n = 624, median age = 14.4 years, 58% male, 8.7% Hispanic) and followed them prospectively for 3 years. Mixed meal tolerance tests (MMTT) were performed within 6 months following clinical diagnosis and repeated semiannually. Unless otherwise indicated, analyses were adjusted for age, sex, BMI Z-score, and diabetes duration. RESULTS: At T1D clinical diagnosis, Hispanics, compared with non-Hispanic whites (NHW), had a higher frequency of diabetic ketoacidosis (DKA) (44.7% vs 25.3%, OR = 2.36, P = 0.01), lower fasting glucose (97 vs 109 mg/dL, P = 0.02) and higher fasting C-peptide (1.23 vs 0.94 ng/mL, P = 0.02) on the first MMTT, and higher frequency of ZnT8 autoantibody positivity (n = 201, 94.1% vs 64%, OR = 7.98, P = 0.05). After exclusion of participants in experimental arms of positive clinical trials, C-peptide area under the curve (AUC) trajectories during the first 3 years after clinical diagnosis were not significantly different between Hispanics and NHW after adjusting for age, sex, BMI-z score, and DKA (n = 413, P = 0.14). CONCLUSION: Despite differences in the metabolic and immunological characteristics at clinical diagnosis of T1D between Hispanics and NHW, C-peptide trajectories did not differ significantly in the first 3 years following clinical diagnosis after adjustment for body mass index and other confounders. These findings may inform the design of observational studies and intervention trials in T1D.

Low-Dose Anti-Thymocyte Globulin Preserves C-Peptide, Reduces HbA1c, and Increases Regulatory to Conventional T-Cell Ratios in New-Onset Type 1 Diabetes: Two-Year Clinical Trial Data.

A three-arm, randomized, double-masked, placebo-controlled phase 2b trial performed by the Type 1 Diabetes TrialNet Study Group previously demonstrated that low-dose anti-thymocyte globulin (ATG) (2.5 mg/kg) preserved ß-cell function and reduced HbA1c for 1 year in new-onset type 1 diabetes. Subjects (N = 89) were randomized to 1) ATG and pegylated granulocyte colony-stimulating factor (GCSF), 2) ATG alone, or 3) placebo. Herein, we report 2-year area under the curve (AUC) C-peptide and HbA1c, prespecified secondary end points, and potential immunologic correlates. The 2-year mean mixed-meal tolerance test-stimulated AUC C-peptide, analyzed by ANCOVA adjusting for baseline C-peptide, age, and sex (n = 82) with significance defined as one-sided P < 0.025, was significantly higher in subjects treated with ATG versus placebo (P = 0.00005) but not ATG/GCSF versus placebo (P = 0.032). HbA1c was significantly reduced at 2 years in subjects treated with ATG (P = 0.011) and ATG/GCSF (P = 0.022) versus placebo. Flow cytometry analyses demonstrated reduced circulating CD4:CD8 ratio, increased regulatory T-cell:conventional CD4 T-cell ratios, and increased PD-1+CD4+ T cells following low-dose ATG and ATG/GCSF. Low-dose ATG partially preserved ß-cell function and reduced HbA1c 2 years after therapy in new-onset type 1 diabetes. Future studies should determine whether low-dose ATG might prevent or delay the onset of type 1 diabetes.

Ethnic differences in progression of islet autoimmunity and type 1 diabetes in relatives at risk.

AIMS/HYPOTHESIS: We hypothesised that progression of islet autoimmunity and type 1 diabetes mellitus differs among races/ethnicities in at-risk individuals. METHODS: In this study, we analysed the data from the Type 1 Diabetes TrialNet Pathway to Prevention Study. We studied 4873 non-diabetic, autoantibody-positive relatives of individuals with type 1 diabetes followed prospectively (11% Hispanic, 80.9% non-Hispanic white [NHW], 2.9% non-Hispanic black [NHB] and 5.2% non-Hispanic other [NHO]). Primary outcomes were time from single autoantibody positivity confirmation to multiple autoantibody positivity, and time from multiple autoantibody positivity to type 1 diabetes mellitus diagnosis. RESULTS: Conversion from single to multiple autoantibody positivity was less common in Hispanic individuals than in NHW individuals (HR 0.66 [95% CI 0.46, 0.96], p = 0.028) adjusting for autoantibody type, age, sex, Diabetes Prevention Trial Type 1 Risk Score and HLA-DR3-DQ2/DR4-DQ8 genotype. In participants who screened positive for multiple autoantibodies (n = 2834), time to type 1 diabetes did not differ by race/ethnicity overall (p = 0.91). In children who were <12 years old when multiple autoantibody positivity was determined, being overweight/obese had differential effects by ethnicity: type 1 diabetes risk was increased by 36% in NHW children (HR 1.36 [95% CI 1.04, 1.77], p = 0.024) and was nearly quadrupled in Hispanic children (HR 3.8 [95% CI 1.6, 9.1], p = 0.0026). We did not observe this interaction in participants who were ≥12 years old at determination of autoantibody positivity, although this group size was limited. No significant differential risks were observed between individuals of NHB and NHW ethnicity. CONCLUSIONS/INTERPRETATION: The risk and rate of progression of islet autoimmunity were lower in Hispanic compared with NHW at-risk individuals, while significant differences in the development of type 1 diabetes were limited to children <12 years old and were modified by BMI.

G-CSF and Exenatide Might Be Associated with Increased Long-Term Survival of Allogeneic Pancreatic Islet Grafts.

BACKGROUND: Allogeneic human islet transplantation is an effective therapy for the treatment of patients with Type 1 Diabetes (T1D). The low number of islet transplants performed worldwide and the different transplantation protocols used limit the identification of the most effective therapeutic options to improve the efficacy of this approach. METHODS: We present a retrospective analysis on the data collected from 44 patients with T1D who underwent islet transplantation at our institute between 2000 and 2007. Several variables were included: recipient demographics and immunological characteristics, donor and transplant characteristics, induction protocols, and additional medical treatment received. Immunosuppression was induced with anti-CD25 (Daclizumab), alone or in association with anti-tumor necrosis factor alpha (TNF-α) treatments (Etanercept or Infliximab), or with anti-CD52 (Alemtuzumab) in association with anti-TNF-α treatments (Etanercept or Infliximab). Subsets of patients were treated with Filgrastim for moderate/severe neutropenia and/or Exenatide for post prandial hyperglycemia. RESULTS: The analysis performed indicates a negative association between graft survival (c-peptide level ≥ 0.3 ng/ml) and islet infusion volume, with the caveat that, the progressive reduction of infusion volumes over the years has been paralleled by improved immunosuppressive protocols. A positive association is instead suggested between graft survival and administration of Exenatide and Filgrastim, alone or in combination. CONCLUSION: This retrospective analysis may be of assistance to further improve long-term outcomes of protocols for transplant of islets and other organs.

Clinical use of fructosamine in islet transplantation.

Many islet transplant recipients have medical conditions that could interfere with the accuracy of HbA1c measurements (e.g., anemia/dapsone use). Fructosamine is less prone to have clinical interferences and reflects glucose control in a shorter period of time than HbA1c. This study aimed to validate fructosamine use in islet transplant subjects and to evaluate its effectiveness as a predictor for islet graft dysfunction. Thirty-three islet transplant recipients who had concomitant fructosamine and HbA1c data available were retrospectively analyzed. HbA1c, fructosamine, mean capillary blood glucose, and islet graft function (fasting C-peptide/glucose ratio) were assessed. There was a significant and positive association between fructosamine and HbA1c (p < 0.0001). Both variables were also positively associated with mean overall and fasting capillary glucose. Neither fructosamine nor HbA1c was shown by ROC analysis to significantly discriminate between periods with and without subsequent graft dysfunction. HbA1c >6% was predictive of this outcome 1 month in advance (OR 2.95, p = 0.003). However, although significantly associated with graft dysfunction, use of this cutoff as a predictor of dysfunction has poor sensitivity (50%) and specificity (77.6%). Fructosamine above the normal range (>270 mumol/L Quest Diagnostics) was also predictive of ensuing dysfunction (OR 2.47, p = 0.03); however, it had similarly poor sensitivity (62%) and specificity (64%). Fructosamine can be used as an alternative to HbA1c for glycemic assessment in islet transplant recipients in situations with HbA1c assay interference. Neither HbA1c nor fructosamine are good predictors of islet graft dysfunction.

Early metabolic markers of islet allograft dysfunction.

BACKGROUND: Islet transplantation can restore normoglycemia to patients with unstable type 1 diabetes mellitus, but long-term insulin independence is usually not sustained. Identification of predictor(s) of islet allograft dysfunction (IGD) might allow for early intervention(s) to preserve functional islet mass. METHODS: Fourteen islet transplantation recipients with long-term history of type 1 diabetes mellitus underwent metabolic testing by mixed meal tolerance test, intravenous glucose tolerance test, and arginine stimulation test every 3 months postislet transplant completion. Metabolic responses were compared between subjects who maintained insulin independence at 18 months (group 1; n=5) and those who restarted insulin within 18 months (group 2; n=9). Data were analyzed before development of islet graft dysfunction and while insulin independent. RESULTS: The 90-min glucose, time-to-peak C-peptide, and area under the curve for glucose were consistently higher in group 2 and increased as a function of time. At 12 months, acute insulin release to glucose in group 2 was markedly reduced as compared with baseline (5.62+/-1.21 microIU/mL, n=4 vs. 16.14+/-3.69 microIU/mL, n=8), whereas it remained stable in group 1 (22.36+/-4.98 microIU/mL, n=5 vs. 27.70+/-2.83 microIU/mL, n=5). Acute insulin release to glucose, acute C-peptide release to glucose (ACpRg), and mixed meal stimulation index were significantly decreased and time-to-peak C-peptide, 90-min glucose, and area under the curve for glucose were significantly increased when measured at time points preceding intervals where IGD occurred compared with intervals where there was no IGD. CONCLUSIONS: The intravenous glucose tolerance test and mixed meal tolerance test may be useful in the prediction of IGD and should be essential components of the metabolic testing of islet transplant recipients.

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.

Islet transplantation with alemtuzumab induction and calcineurin-free maintenance immunosuppression results in improved short- and long-term outcomes.

BACKGROUND: Only a minority of islet transplant recipients maintain insulin independence at 5 years under the Edmonton protocol of immunosuppression. New immunosuppressive strategies are required to improve long-term outcomes. MATERIALS AND METHODS: Three subjects with unstable type 1 diabetes mellitus underwent islet transplantation with alemtuzumab induction and sirolimus-tacrolimus maintenance for 3 months and then sirolimus-mycophenolic acid maintenance thereafter. Follow-up was more than 2 years. Comparison was with 16 historical subjects transplanted under the Miami version of the Edmonton protocol. RESULTS: Insulin independence was achieved in 2 of 3 alemtuzumab and 14 of 16 historical subjects. Those who did not achieve insulin independence only received a single islet infusion. Insulin-independence rates remained unchanged in the alemtuzumab group, but decreased from 14 of 16 (88%) to 6 of 16 (38%) in the historical group over 2 years. Insulin requirements increased in the historical group while remaining stable in the alemtuzumab group. Comparison of functional measures at 3 months suggested better engraftment with alemtuzumab (P=NS). Further comparison of alemtuzumab versus historical groups, up to 24 months, demonstrated significantly better: Mixed meal stimulation index (24 months, 1.0+/-0.08 [n=3] vs. 0.5+/-0.06 pmol/mL [n=6], P<0.01), mixed meal peak C-peptide (24 months, 5.0+/-0.5 [n=3] vs. 3.1+/-0.3 nmol/mL [n=6], P<0.05), HbA1c (24 months, 5.4+/-0.15 [n=3] vs. 6.3+/-0.12 pmol/mL [n=10], P<0.01). Administration of alemtuzumab was well tolerated. There was no increased incidence of infections in alemtuzumab subjects despite profound, prolonged lymphocyte depletion. CONCLUSIONS: Islet transplantation with alemtuzumab induction was well tolerated and resulted in improved short- and long-term outcomes. Further investigation is underway for validation.