[Show abstract][Hide abstract] ABSTRACT: The Collaborative Islet Transplant Registry (CITR) collects data on clinical islet isolations and transplants. This retrospective report analyzed 1017 islet isolation procedures performed for 537 recipients of allogeneic clinical islet transplantation in 1999–2010. This study describes changes in donor and islet isolation variables by era and factors associated with quantity and quality of final islet products. Donor body weight and BMI increased significantly over the period (p < 0.001). Islet yield measures have improved with time including islet equivalent (IEQ)/particle ratio and IEQs infused. The average dose of islets infused significantly increased in the era of 2007–2010 when compared to 1999–2002 (445.4 ± 156.8 vs. 421.3 ± 155.4 ×103 IEQ; p < 0.05). Islet purity and total number of β cells significantly improved over the study period (p < 0.01 and <0.05, respectively). Otherwise, the quality of clinical islets has remained consistently very high through this period, and differs substantially from nonclinical islets. In multivariate analysis of all recipient, donor and islet factors, and medical management factors, the only islet product characteristic that correlated with clinical outcomes was total IEQs infused. This analysis shows improvements in both quantity and some quality criteria of clinical islets produced over 1999–2010, and these parallel improvements in clinical outcomes over the same period.
American Journal of Transplantation 10/2014; · 6.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The effects of glucocorticoid during culture on human islet cells have been controversial. Exendin-4 (EX) enhances the insulin secretion and significantly improves clinical outcomes in islet cell transplantation. In this study, we examined the effects of glucocorticoids and EX on human islet cells during pretransplant culture.
[Show abstract][Hide abstract] ABSTRACT: Objective: We evaluated whether 1,5-anhydroglucitol(1,5-AG) (Glycomark®), a test for measuring post-prandial glucose and glucose variability, could be a tool for assessing short term glycemic control in islet cell transplant (ICT) subjects.Research Design and Methods: Data of 21 subjects with type-1 DM and allogenic islet transplantation, who had concomitant fructosamine, HbA1c, 1,5-AG (n=85 samples) and capillary glucose self-monitoring measurements (n=2979) were analyzed retrospectively at different time points after ICT.Results: A significant negative association was observed between 1,5-AG and HbA1c (p=0.02), but not with fructosamine. When HbA1c was divided in quartiles as <5.6, 5.6-5.9, 5.9-6.2 and >6.2, a decrease of an estimated 0.70±0.30 μg/mL in 1,5-AG was associated with each quartile of increase in HbA1c(p<0.0001). There was a significant decline of 1.64+/-0.3mg/dL in post-prandial glucose values for each 1 unit increase in 1,5-AG(p<0.0001). For those with HbA1c≥6.0% when 1,5-AG was ≥8.15 μg/mL, the mean estimated glucose level was 103.71+/-3.66mg/dl; whereas it was 132.12+/-3.71mg/dl when 1,5-AG was <8.15 μg/mL. The glucose variability (Glumax-Glumin(in subjects with 1,5-AG <8.15 μg/mL, was 46.23mg/dl greaterthan the subjects with 1,5-AG ≥8.15 μg/mL (HbA1c ≥ 6.0%). There was no significant association between glycomark and glucose variability where HbA1c <6%./,Conclusions: 1,5-AG significantly associated with post-prandial glucose levels and glucose variability in ICT recipients with near normal HbA1c (6.0%-6.5%) levels. These findings suggest that 1,5-AG can be used to differentiate those ICT subjects with higher glucose variability despite having near normal HbA1c. However, prospective studies are needed to evaluate the association between glycomark levels and the parameters of graft dysfunction/failure.
[Show abstract][Hide abstract] ABSTRACT: Allogeneic islet transplantation (IT) provokes changes in metabolic responses and nutritional behaviors. The durability of these changes needs to be described as well as their impact on the recipients' lifestyle. The goal of this study was to investigate how islet transplantation influenced diet, exercise habits, and body composition during 10 years after IT. A retrospective study performed in 33 (14 males, 19 females) IT recipients used dietary, physical activity open- ended questionnaire and anthropometric measurements. Data were collected before transplantation, every 3 months up to the 18th and every 6 months thereafter. Data were grouped by gender and eras: pre-IT; 0-3 years; 4-6 years, and 7-10 years after IT. Reduction in body mass index (BMI) from pre-IT to 0-3 years was noted: 23.68 ± 2,18 kg/m(2) to 22.07 ± 2.94 kg/m(2) (P < .05). Increased values were observed from 0-3 years to 4-6 years in: waist circumference (WC) (76.68 ± 7.22 to 79.44 ± 7.58 cm), BMI (23,68 ± 2,18 to 22,75 ± 3,11 kg/m(2)) and weight (64.69 ± 11.98 to 67.43 ± 14 kg): (P < .03). WC increased continuously up to 7-10 years (86.33 ± 9.45 cm; P < .05). There was an average of 5.3 ± 5.6 h/wk of exercise during follow-up. From pre-IT to 0-3 years there was a 19% reduction in protein consumption (P < .05) and a 39% increase in calories from saturated fats (P < .05). A trend to reduce carbohydrates intake noted from pre-IT to 0-3 years was progressively inverted from then throughout 7-10 years (not significant). IT was associated with a significantly decreased BMI early on that it was not sustained. The subsequent weight gain and WC increase could be the result of chronic immunosuppressive therapy and/or voluntary change in eating habits. The increased consumption of carbohydrates could be related to an adaptation of a lifestyle or/and reintroduction of insulin after graft dysfunction. Active lifestyle might be result of the intensive clinical care after IT, concomitant awareness of the importance of routine physical exercise on blood glucose control, and diabetes management. Continuous follow-up of IT recipients is needed to better understand these changes and for comparison with subjects with type 1 diabetes mellitus.
[Show abstract][Hide abstract] ABSTRACT: To evaluate the effect of lysofylline (LSF) induction therapy on immune responses in the early post-transplant period after islet infusion, we followed 13 islet transplant recipients for changes in levels of peri-transplant cytokines, whole blood lymphocyte phenotype and gene expression. All recipients received thymoglobulin, sirolimus, tacrolimus and enbrel, and 5/13 also received LSF treatments. Total lymphocytes, T and T cell subsets decreased to lower levels than B and NK cells after transplant. Recovery of lymphocytes and T cells was similar between control and LSF groups. B and NK cells recovered faster than T cells in both groups, but LSF group had higher B cell levels compared to controls. Levels of CD4+/CD25bright/Foxp3+ cells were higher in LSF group compared to controls. LSF group had lower levels of granzyme B (GB) and perforin in both T and NK cells. Serum cytokines in LSF group had a trend towards lower levels of TNF-α and IL1-β and higher levels of IFN-γ, IL-6 and IL-10. Expression of the cytotoxic lymphocyte (CL) genes GB, perforin, and fas ligand and TNF-α gene was lower in LSF group compare to controls. For the one patient in the control group with complete loss of graft function (undetectable c-peptide), expression of CL, IL-4, IL-6, IL-10, TNF-α, IFN-γ, TGF-β, and Foxp3 genes was increased. Overall, the data suggest trends towards reduced immunoreactivity in the LSF treated group.
2013 Clinical Immunology Society Annual Meeting; 04/2013
[Show abstract][Hide abstract] ABSTRACT: To describe trends of primary efficacy and safety outcomes of islet transplantation in type 1 diabetes recipients with severe hypoglycemia from the Collaborative Islet Transplant Registry (CITR) from 1999 to 2010.
A total of 677 islet transplant-alone or islet-after-kidney recipients with type 1 diabetes in the CITR were analyzed for five primary efficacy outcomes and overall safety to identify any differences by early (1999-2002), mid (2003-2006), or recent (2007-2010) transplant era based on annual follow-up to 5 years.
Insulin independence at 3 years after transplant improved from 27% in the early era (1999-2002, n = 214) to 37% in the mid (2003-2006, n = 255) and to 44% in the most recent era (2007-2010, n = 208; P = 0.006 for years-by-era; P = 0.01 for era alone). C-peptide ≥0.3 ng/mL, indicative of islet graft function, was retained longer in the most recent era (P < 0.001). Reduction of HbA(1c) and resolution of severe hypoglycemia exhibited enduring long-term effects. Fasting blood glucose stabilization also showed improvements in the most recent era. There were also modest reductions in the occurrence of adverse events. The islet reinfusion rate was lower: 48% by 1 year in 2007-2010 vs. 60-65% in 1999-2006 (P < 0.01). Recipients that ever achieved insulin-independence experienced longer duration of islet graft function (P < 0.001).
The CITR shows improvement in primary efficacy and safety outcomes of islet transplantation in recipients who received transplants in 2007-2010 compared with those in 1999-2006, with fewer islet infusions and adverse events per recipient.
Diabetes care 07/2012; 35(7):1436-45. · 7.74 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The seemingly inexorable decline in insulin independence after islet transplant alone (ITA) has raised concern about its clinical utility. We hypothesized that induction immunosuppression therapy determines durability of insulin independence. We analyzed the proportion of insulin-independent patients following final islet infusion in four groups of ITA recipients according to induction immunotherapy: University of Minnesota recipients given FcR nonbinding anti-CD3 antibody alone or T cell depleting antibodies (TCDAb) and TNF-α inhibition (TNF-α-i) (group 1; n = 29); recipients reported to the Collaborative Islet Transplant Registry (CITR) given TCDAb+TNF-α-i (group 2; n = 20); CITR recipients given TCDAb without TNF-α-i (group 3; n = 43); and CITR recipients given IL-2 receptor antibodies (IL-2RAb) alone (group 4; n = 177). Results were compared with outcomes in pancreas transplant alone (PTA) recipients reported to the Scientific Registry of Transplant Recipients (group 5; n = 677). The 5-year insulin independence rates in group 1 (50%) and group 2 (50%) were comparable to outcomes in PTA (group 5: 52%; p>0.05) but significantly higher than in group 3 (0%; p = 0.001) and group 4 (20%; p = 0.02). Induction immunosuppression was significantly associated with 5-year insulin independence (p = 0.03), regardless of maintenance immunosuppression or other factors. These findings support potential for long-term insulin independence after ITA using potent induction therapy, with anti-CD3 Ab or TCDAb+TNF-α-i.
American Journal of Transplantation 04/2012; 12(6):1576-83. · 6.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to identify predictors of insulin independence and to establish the best clinical tools to follow patients after pancreatic islet transplantation (PIT). Sequential metabolic responses to intravenous (I.V.) glucose (I.V. glucose tolerance test [IVGTT]), arginine and glucose-potentiated arginine (glucose-potentiated arginine-induced insulin secretion [GPAIS]) were obtained from 30 patients. We determined the correlation between transplanted islet mass and islet engraftment and tested the ability of each assay to predict return to exogenous insulin therapy. We found transplanted islet mass within an average of 16 709 islet equivalents per kg body weight (IEQ/kg BW; range between 6602 and 29 614 IEQ/kg BW) to be a poor predictor of insulin independence at 1 year, having a poor correlation between transplanted islet mass and islet engraftment. Acute insulin response to IVGTT (AIR(GLU) ) and GPAIS (AIR(max) ) were the most accurate methods to determine suboptimal islet mass engraftment. AIR(GLU) performed 3 months after transplant also proved to be a robust early metabolic marker to predict return to insulin therapy and its value was positively correlated with duration of insulin independence. In conclusion, AIR(GLU) is an early metabolic assay capable of anticipating loss of insulin independence at 1 year in T1D patients undergoing PIT and constitutes a valuable, simple and reliable method to follow patients after transplant.
American Journal of Transplantation 02/2012; 12(5):1275-89. · 6.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Pancreatic islet transplantation is a promising treatment option for patients severely affected with type 1 diabetes. This report from CITR presents pre- and posttransplant human leukocyte antigen (HLA) class I sensitization rates in islet-alone transplantation. Data came from 303 recipients transplanted with islet-alone between January 1999 and December 2008. HLA class I sensitization was determined by the presence of anti-HLA class I antibodies. Panel-reactive antibodies (PRA) from prior to islet infusion and at 6 months, and yearly posttransplant was correlated to measures of islet graft failure. The cumulative number of mismatched HLA alleles increased with each additional islet infusion from a median of 3 for one infusion to 9 for three infusions. Pretransplant PRA was not predictive of islet graft failure. However, development of PRA >20% posttransplant was associated with 3.6-fold (p < 0.001) increased hazard ratio for graft failure. Patients with complete graft loss who had discontinued immunosuppression had significantly higher rate of PRA ≥ 20% compared to those with functioning grafts who remained on immunosuppression. Exposure to repeat HLA class I mismatch at second or third islet infusions resulted in less frequent development of de novo HLA class I antibodies when compared to increased class I mismatch. The development of HLA class I antibodies while on immunosuppression is associated with subsequent islet graft failure. The risk of sensitization may be reduced by minimizing the number of islet donors used per recipient, and in the absence of donor-specific anti-HLA antibodies, repeating HLA class I mismatches with subsequent islet infusions.
[Show abstract][Hide abstract] ABSTRACT: To evaluate the effect of exenatide on gastric emptying and long-term metabolic control.
Ten islet allograft recipients treated with exenatide up to 4 years. Data from a mixed meal test with (MMT+) versus without (MMT-) administration of exenatide before boost ingestion were analyzed at 6, 12, 24, 36, or 48 months after initiation of exenatide treatment. None of the subjects were symptomatic for gastroparesis before or during the study. The c-peptide, acetaminophen absorption and glucose responses to MMT were analyzed by Student t test and analysis of variance.
Average exenatide dose was 12.75 ± 9.46 μg/dL. The MMT subjects included two groups those with acetaminophen peak ≤120 minutes ("good gastric emptying; n = 4") versus those with an acetaminophen peak ≥180 minutes ("delayed gastric emptying"). Among the MMT+, acetaminophen absorption was the same in both groups (P = .27). Up to 48 months exenatide delayed time to peak of glucose, c-peptide, and acetaminophen as well as suppressed the glucagon response to MMT mean peak: 70.89 ± 12.45 versus 43.24 ± 4.67. The mean values of c-peptide and glucose responses to MMT were not significantly different.
Long-term exenatide administration up to 4 years was safe in islet transplant recipients, even in the presence of delayed gastric emptying. The effects of exenatide were acute and reversible when the agent was withdrawn. The main difficulty with the use of exenatide in islet transplant subjects is their poor tolerability, although the physiological effects are clearly evident even at low doses. Approximately 63% of total subjects under exenatide treatment discontinued the drug due to nausea and vomiting. The use of new GLP1 analogs with longer half lives and fewer side effects may help to attain higher GLP1 levels, therefore improving islet function and survival.
[Show abstract][Hide abstract] ABSTRACT: The selection of enzyme blend is critical for the success of human islet isolations. Liberase HI collagenase (Roche) was introduced in the 1990s and had been widely used for clinical islet transplantation. More recently, a blend collagenase NB1 has been rendered available. The aim of this study was to evaluate the isolation outcomes and islet quality comparing human islet cells processed using NB1 and Liberase HI. A total of 90 isolations processed using NB1 (n = 40) or Liberase HI (n = 50) was retrospectively analyzed. Islet yield, function in vitro and in vivo, cellular (including β-cell-specific) viability and content, as well as isolation-related factors were compared. No significant differences in donor-related factors were found between the groups. There were also no significant differences in islet yields (NB1 vs. Liberase: 263,389 ± 21,550 vs. 324,256 ± 27,192 IEQ; p = n.s., respectively). The pancreata processed with NB1 showed a significantly longer digestion time (18.6 ± 0.7 vs. 14.5 ± 0.5 min, p < 0.01), lower β-cell viability (54.3 ± 3.4% vs. 72.0 ± 2.1%, p < 0.01), β-cell mass (93,671 ± 11,150 vs. 148,961 ± 12,812 IEQ, p < 0.01), and viable β-cell mass (47,317 ± 6,486 vs. 106,631 ± 10,228 VβIEQ, p < 0.01) than Liberase HI. In addition, islets obtained with Liberase showed significantly better graft function in in vivo assessment of islet potency. The utilization of collagenase NB1 in human islet isolation was associated with significantly lower β-cell viability, mass, and islet potency in vivo in our series when compared to Liberase HI, even though there was no significant difference in islet yields between the groups. Evaluation of viable β-cell mass contained in human islet preparations will be useful for selecting enzyme blends.
[Show abstract][Hide abstract] ABSTRACT: Pancreatic islet allotransplantation is an option for patients with unstable type 1 diabetes mellitus (T1DM). Major improvements in islet isolation techniques and the implementation of steroid-free immunosuppressive regimens can maintain insulin independence in the majority of T1DM for at least 1 year after transplantation. Recent studies have emphasized the impact of sirolimus on female reproductive tract. In this letter we report on the alterations of the female reproductive tract in 18 chronically immunosuppressed patients with T1DM following allogenic islet transplantation. Previous research has shown development of ovarian cysts in islet transplant patients receiving sirolimus. We extensively re-evaluated this and other possible side effects on the female reproductive system. These side effects have been underestimated although they are significant, requiring surgical or intensive medical treatment. Pre and post-transplant gynecological evaluation should be performed to address the development of complications secondary to sirolimus in order to intervene sooner with alternative therapies.
[Show abstract][Hide abstract] ABSTRACT: There is a need for biomarkers to monitor the development and progression of type 1 DM. We analyzed mRNA expression levels for granzyme B, perforin, fas ligand, TNF-α, IFN-γ, Foxp3, IL-10, TGF-β, IL-4, IL-6, IL-17, Activation-induced cytidine deaminase (AID) and Immunoglobulin G gamma chain (IgG ) genes in peripheral blood of at-risk, new-onset and long-term type 1 DM , and healthy controls. The majority of the genes were suppressed in long-term type 1 DM compared to controls and new-onset patients. IFN-γ, IL-4 and IL-10 mRNA levels were significantly higher in new-onset compared to at-risk and long-term groups. There was decreased mRNA expression for AID and IgG and up-regulation of IFN-γ with age in controls. Data suggest an overall depressed immunity in long-term type 1 DM. Increased gene expression levels for IFN-γ, IL-4 and IL-10 in new-onset patients from at-risk patients might be used as potential markers for progression of the disease.
[Show abstract][Hide abstract] ABSTRACT: Islet isolation and purification using a continuous density gradient may reduce the volume of tissue necessary for implantation into patients, therefore minimizing the risks associated with intraportal infusion in islet transplantation. On the other hand, the purification procedure might result in a decreased number of islets recovered due to various stresses such as exposure to cytokine/chemokine. While a Ficoll-based density gradient has been widely used in purification for clinical trials, purification with iodixanol (OptiPrep) has been recently reported in islet transplant series with successful clinical outcomes. The aim of the current study was to compare the effects of the purification method using OptiPrep-based and Ficoll-based density gradients. Human islet isolations were performed using a modified automated method. After the digestion phase, pre-purification digests were divided into two groups and purified using a semiautomated cell processor with either a continuous Ficoll- or OptiPrep-based density gradient. The quantity, purity, viability, and cellular composition of islet preparations from each group were assessed. Cytokine/chemokine and tissue factor production from islet preparations after 48-h culture were also measured. Although islet purity, post-purification IEQ, islet recovery rate, FDA/PI, and fractional β-cell viability were comparable, β-cell mass after 48-h culture significantly improved in the OptiPrep group when compared to the Ficoll group. The production of cytokine/chemokine including IL-1β, TNF-α, IFN-γ, IL-6, IL-8, MIP-1β, MCP-1, and RANTES but not tissue factor from the OptiPrep group was significantly lower during 48-h culture after isolation. Each preparation contained the similar number of ductal cells and macrophages. Endotoxin level in both gradient medium was also comparable. The purification method using OptiPrep gradient media significantly reduced cytokine/chemokine production but not tissue factor from human islet preparations and improved β-cell survival during pretransplant culture. Our results suggest that the purification method using OptiPrep gradient media may be of assistance in increasing successful islet transplantation.
[Show abstract][Hide abstract] ABSTRACT: Pancreatic islet transplantation (PIT) represents a potential curative treatment for patients with type 1 diabetes, but only 10-15% of patients remain insulin independent 5 years post-transplant. It is not known whether intrinsic insulin resistance exacerbated by immunosuppression plays a pivotal role in low graft survival. The study objective was to understand the changes in insulin resistance, glucose effectiveness (S(g)) and free fatty acid dynamics (FFAd) before and after PIT.
Insulin sensitivity index (S(i)), S(g) and FFAd were measured before and after PIT in 10 lean patients, 8 of whom reached insulin independence. Modified Bergman minimal model of frequently sampled intravenous glucose tolerance tests were performed pretransplant and at 12 months post-transplant. Nine non-diabetic control (NDC) subjects matched by age, gender and BMI were used.
Pretransplant S(i) and S(g) were 3.5 ± 0.8 × 10(-5)/min/(pmol/l) and 0.74 ± 0.24 × 10(-2)/min, respectively. S(i) was significantly lower than matched NDCs [10.8 ± 0.6 × 10(-5)/min/(pmol/l), p < 0.004]; S(g) did not reach statistical significance (1.27 ± 0.22 × 10(-2)/min, p = 0.25). Compared to pretransplant values, mean post-transplant S(i) and S(g) were 9.6 ± 1.3 × 10(-5)/min/(pmol/l)and 1.28 ± 0.22 ×10(-2)/min, respectively, indicating significant improvement for S(i) but not S(g) (p = 0.008 and p = 0.06). Twelve-month post-PIT compared to NDC values were not significantly different (p = 0.58 and 0.97, respectively). In addition, fractional disposal rate for FFA which directly depends on the endogenous insulin release (10-20 min) nearly normalized after PIT (p = 0.06).
These preliminary findings demonstrate that PIT can restore glucose disposal and insulin sensitivity and partially correct glucose effectiveness and FFAd.
Diabetes Obesity and Metabolism 11/2010; 12(11):994-1003. · 5.18 Impact Factor