Improved outcomes of islet autotransplant after total pancreatectomy by combined blockade of IL-1ß and TNFα.

The efficacy of islet transplant is compromised by a significant loss of islet mass posttransplant due to an innate inflammatory reaction. We report the use of a combination of etanercept and anakinra (ANA+ETA) to block inflammatory islet damage in 100 patients undergoing total pancreatectomy with islet autotransplant. The patients were divided into 3 groups: no treatment (control [CTL]), etanercept alone (ETA), or a combination of etanercept and anakinra (ANA+ETA). Peritransplant serum samples were analyzed for protein markers of islet damage and for inflammatory cytokines. Graft function was assessed by fasting blood glucose, basal C-peptide, secretory unit of islet transplant objects (SUITO) index, and hemoglobin A1c . Administration of both antiinflammatory drugs was well tolerated without any major adverse events. Reductions in interleukin-6, interleukin-8, and monocyte chemoattractant protein 1 were observed in patients receiving ANA+ETA compared with the CTL group, while also showing a modest improvement in islet function as assessed by basal C-peptide, glucose, hemoglobin A1c , and SUITO index but without differences in insulin dose. These results suggest that double cytokine blockade (ANA+ETA) reduces peritransplant islet damage due to nonspecific inflammation and may represent a promising strategy to improve islet engraftment, leading to better transplant outcomes.

Islet product characteristics and factors related to successful human islet transplantation from the Collaborative Islet Transplant Registry (CITR) 1999-2010.

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±155.4×0(3) IEQ; p<0.05). Islet purity and total number of ß 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.

Evidence for instant blood-mediated inflammatory reaction in clinical autologous islet transplantation.

A nonspecific inflammatory and thrombotic reaction termed instant blood-mediated inflammatory reaction (IBMIR) has been reported when allogenic or xenogenic islets come into contact with blood. This reaction is known to cause significant loss of transplanted islets. We hypothesized that IBMIR occurs in patients undergoing total pancreatectomy followed by autologous islet transplantation (TP-AIT) and tested this hypothesis in 24 patients and in an in vitro model. Blood samples drawn during the peritransplant period showed a significant and rapid increase of thrombin-anti-thrombin III complex (TAT) and C-peptide during islet infusion, which persisted for up to 3 h, along with a decreased platelet count. A concomitant increase in levels of inflammatory proteins IL-6, IL-8 and interferon-inducible protein-10 was observed. An in vitro model composed of pure islets plus autologous blood also demonstrated significantly increased levels of TAT (p<0.05), C-peptide (p<0.05), tumor necrosis factor-alpha (p<0.05) and MCP-1 (p<0.05), as well as strong tissue factor expression in islets. Islet viability decreased significantly but was rescued by the presence of low-molecular-weight dextran sulfate. In conclusion, AIT-induced elevation of TAT and destruction of islets suggests that IBMIR might occur during AIT. Modulating this process may help improve islet engraftment and the insulin independence rate in TP-AIT patients.

Withaferin A inhibits pro-inflammatory cytokine-induced damage to islets in culture and following transplantation.

AIMS/HYPOTHESIS: Beta cell death triggered by pro-inflammatory cytokines plays a central role in the pathogenesis of type 1 diabetes and loss of transplanted islets. The nuclear factor κB (NF-κB) signalling pathway is a key regulator of beta cell stress response, survival and apoptosis. Withaferin A (WA), a steroidal lactone derived from Withania somnifera, has been demonstrated to be a potent, safe, anti-inflammatory molecule that can inhibit NF-κB signalling. Therefore, we evaluated the ability of WA to protect mouse and human islets from the damaging effects of pro-inflammatory cytokines in vitro and following intraportal transplantation. METHODS: Mouse and human islets were treated with a cytokine cocktail, and NF-κB activation was measured by immunoblots, p65 nuclear translocation and chromatin immunoprecipitation of p65-bound DNA. Intraportal transplantation of a marginal mass of syngeneic mouse islets was performed to evaluate the in vivo protective effect of WA. RESULTS: Treatment with WA substantially improved islet engraftment of syngeneic islets (83% for infusion with 200 islets + WA; 0% for 200 islets + vehicle) in a mouse model of diabetes, compared with marginal graft controls with superior islet function in WA-treated mice confirmed by glucose tolerance test. Treatment of human and mouse islets with WA prevented cytokine-induced cell death, inhibited inflammatory cytokine secretion and protected islet potency. CONCLUSIONS: WA was shown to be a strong inhibitor of the inflammatory response in islets, protecting against cytokine-induced cell damage while improving survival of transplanted islets. These results suggest that WA could be incorporated as an adjunctive treatment to improve islet transplant outcome.

High-mobility group box 1 expressions in hypoxia-induced damaged mouse islets.

INTRODUCTION: Discovering a new, accurate, and useful damage marker for isolated islets is critical for avoiding the transplantation of nontherapeutic preparations. Recently, we have reported that islets that contained uniquely high levels of high-mobility group box 1 (HMGB1) protein and cytokine induced damaged islets released HMGB1 in a mouse model. Islets are frequently exposed to hypoxic conditions during organ procurement, organ transportation, islet isolation, and islet storage before transplantation. In the present study, we analyzed HMGB1 expressions in hypoxia-induced damaged mouse islets. METHODS: Damaged mouse islets were generated by hypoxic conditions (1% O2, 5% CO(2), and 94% N(2)). HMGB1 expressions and production levels were assessed by quantitative real-time polymerase chain reaction (PCR), Western blotting, and enzyme-linked immunosorbent assay (ELISA) studies. In vivo islet function was analyzed using transplantation assay using streptozotocin-induced diabetic mice. RESULTS: HMGB1 was mainly stained in the nucleus in the intact islets; however, HMGB1 was present in not only the nucleus, but also the cytoplasm in hypoxia-induced damaged islets. HMGB1 messenger RNA (mRNA) levels were up-regulated in the hypoxia-induced damaged islets, suggesting that HMGB1 was intentionally generated during hypoxia. HMGB1 protein levels in the islets were gradually decreased with time under hypoxic conditions. The amount of released HMGB1 levels and the amount of released HMGB1 levels per hour were significantly increased in damaged (noncurable) islets. CONCLUSIONS: When islets were damaged by hypoxic condition, HMGB1 was synthesized and released from hypoxia-induced damaged islets. The amount of released HMGB1 and/or the amount of released HMGB1 per hour might be a useful marker for detecting damaged islets and might be used for islet potency assay.

An effective method to release human islets from surrounding acinar cells with agitation in high osmolality solution.

INTRODUCTION: Islet purification is mainly performed by the density gradient method. However, purification of the embedded islets that are surrounded by exocrine tissue should be difficult, because their density is similar to exocrine tissue. In this study, we performed chart review to assess the relationship between the ratio of embedded islets and efficacy of purification. Then, we tested several conditions of a new method to free the islets from surrounded exocrine tissues using high osmolality solution with gentle agitation. MATERIALS AND METHODS: First, we performed chart review of our human islet isolation. Second, embedded islet-enriched human islet fractions (embedded islets >50%) were suspended in University of Wisconsin (UW) solution (UW group, 320 mOsm/kg/H(2)0) or osmolality-adjusted UW solution (400, 500, and 600 mOsm/kg/H(2)0; 400 group, 500 group, and 600 group, respectively). Each tube was gently shaken at 4°C. The tissue samples were taken before shaking and after 15, 30, and 60 minutes. Islet yield, percentage of embedded islets, and viabilities were assessed. RESULTS: The chart review revealed that high ratio of embedded islets deteriorated the efficacy of islet purification. The islet yield in all groups except for the 600 group did not change at 15 minutes, but it decreased in all groups at 60 minutes. The average percentage of embedded islets before shaking was 62.6%. Although percentage of embedded islets were decreasing in all groups, it was < 20% at 15 minutes in the 500 and 600 groups whereas it was >44% in the UW group, which indicated that higher osmolality would have a greater effect. Viability was >95% in all groups at 30 minutes. CONCLUSIONS: The embedded islets deteriorated the efficacy of islet purification. Gentle agitation of embedded islets in high osmolality (500 mOsm/kg/H(2)O, 15 minutes) could release islets from surrounded exocrine tissue.

Usefulness of the secretory unit of islet transplant objects (SUITO) index for evaluation of clinical autologous islet transplantation.

BACKGROUND: Assessing the engrafted islet mass is important in evaluating the efficacy of islet transplantation. We previously demonstrated that the average secretory unit of islet transplant objects (SUITO) index within 1 month of allogeneic islet transplantation was an excellent predictor of insulin independence. However, the usefulness of the SUITO index for evaluating autologous islet transplantation has not been explored. The purpose of the present study was to assess the relationship between the SUITO index and clinical outcomes after total pancreatectomy followed by autologous islet transplantation. METHODS: We performed 27 total pancreatectomies followed by autologous islet transplantation from October 2006 to January 2011. Cases were divided into an insulin-independent group (IIG; n = 12) and an insulin-dependent group (lDG; n = 15). The SUITO index was calculated by the formula [fasting C-peptide (ng/mL)/fasting glucose (mg/dL) -63] × 1,500. The average SUITO index within the first month of transplantation except for days 0, 1, and 2, maximum SUITO index, and most recent SUITO index were calculated in each case, and values were compared between the IIG and the IDG. RESULTS: The average SUITO index within 1 month was significantly higher in the IIG than in the IDG (24.6 ± 3.4 vs 14.9 ± 2.0, respectively; P < .02). The maximum SUITO indices were 45.7 ± 7.7 in the IIG and 30.1 ± 8.1 in the IDG (not significant), and the recent SUITO indices were 36.9 ± 6.7 in the IIG and 22.8 ± 6.1 in the IDG (not significant). CONCLUSIONS: The average SUITO index within 1 month was an excellent predictor of insulin independence after total pancreatectomy followed by autologous islet transplantation.

Association between the secretory unit of islet transplant objects index and satisfaction with insulin therapy among insulin-dependent islet recipients.

INTRODUCTION: When patients do not become insulin independent after islet cell transplantation (ICT), another aim is to eliminate severe hypoglycemia. Previously we reported that a secretory unit of islet transplant objects (SUITO) index score >10 was associated with a reduction of severe hypoglycemia. In this study, we assessed patients' satisfaction with their insulin therapy based on the SUITO index. METHODS: The study involved 11 islet recipients with type 1 diabetes who underwent ICT but still used insulin. From those patients, 41 Insulin Therapy Satisfaction Questionnaires (ITSQ) were collected. The SUITO index (fasting C-peptide [ng/mL] × 1500/blood glucose [mg/dL] - 63) was calculated at the same outpatient visits that the survey was administered. ITSQ scores were summarized using subscales and compared among 3 groups: the pre-ICT group, the low-SUITO group (SUITO index score <10 post-ICT), and the high-SUITO group (SUITO index score ≥10). Higher survey scores indicated better satisfaction. RESULTS: Significant trend relationships across the 3 groups were observed in the ITSQ total score (P = .02 with Jonckheere-Terpstra test) and subscale scores of glycemic control (P < .001), hypoglycemic control (P = .01), and inconvenience of regimen (P = .004). The pairwise comparisons between the 3 groups found significant differences: high SUITO versus both pre-ICT and low SUITO for the total ITSQ score (P = .03 and .005, respectively) and glycemic control score (P = .008 and .001, respectively), and high SUITO versus low SUITO for hypoglycemic control score (P = .04) and inconvenience of regimen score (P = .008). CONCLUSION: Islet recipients with a SUITO index ≥10 experienced higher satisfaction with insulin injection therapy compared with the pre-ICT group, even though they were insulin dependent. A SUITO index ≥10 is a reasonable benchmark for successful ICT.

Assessment of human islet isolation with four different collagenases.

BACKGROUND: The isolation of islets from the human pancreas critically depends on the efficiency of the digestive enzymes. Liberase HI had been used as a standard preparation until the issues concerning bovine spongiform encephalopathy. Thus, we must now use other collagenases for clinical islet transplantation, four of which we have evaluated herein. METHODS: The digestion of each of 17 pancreata from brain-dead donors was performed using the following collagenases: Liberase HI (HI; Roche, n = 9); Liberase MTF C/T (MTF; Roche, n = 4); Collagenase NB1 Premium Grade (NB1; Serva, n = 7); or Clzyme Collagenase HA (CI, VitaCyte, n = 4). Islet isolations were based on the Edmonton protocol for HI, whereas our modified islet isolation method was used for the three new enzymes (MTF, NB1, and CI). RESULTS: There were no significant differences in donor age, body mass index, pancreas size, and cold ischemic time among the four groups. The phase I time in the NB1 group was significantly shorter than in the CI group (P = .0014). The prepurification IEQ/g in the HI group was significantly lower than the others (P = .0003 vs MTF, .0007 vs NB1, and .0009 vs CI, respectively). The postpurification IEQ/g in the MTF group was significantly higher than in the HI group (P = .006). The viability in the NB1 group was significantly greater than the HI group (P = .003). CONCLUSION: Three new enzymes (MTF, NB1, and CI) may enable us to obtain higher islet yields than with HI.

Inhibition of inflammatory cytokine-induced response in human islet cells by withaferin A.

BACKGROUND: After islet cell transplantation, a substantial mass of islets are lost owing to nonspecific inflammatory reactions. Cytokine exposure before or after transplantation can upregulate expression of proinflammatory genes via the nuclear factor-kappaB signaling pathway, eventually resulting in islet loss. OBJECTIVE: To test the effects of a naturally occurring nuclear factor-kappaB inhibitor, withaferin A, on regulation of inflammatory genes in human islets. METHODS: Human pancreatic islets were isolated using a modified Ricordi protocol. Purified islets were cultured for 2 days. The effect of withaferin A treatment on islet cell viability was examined using the fluorescein diacetate-propidium iodide dye exclusion test, and on function using a static glucose stimulation assay. Islet cells were treated with a cytokine mixture (50 U/mL of interleukin-1beta, 1000 U/mL of tumor necrosis factor-alpha, and 1000 U/mL of interferon-gamma) for 48 hours with or without withaferin A, 1 microg/mL. Treated islets were used for real-time polymerase chain reaction (PCR) array analysis for expression of inflammatory genes, and expression of other selected genes was analyzed using real-time PCR with single primers. RESULTS: Glucose stimulation and viability assays demonstrated that withaferin A was not toxic to islet cells. Of 84 inflammation-related genes examined using real-time PCR array analysis, 9 were significantly upregulated by cytokine treatment compared with the control group. However, addition of withaferin A to the culture significantly inhibited expression of all genes. CONCLUSION: Withaferin A significantly inhibits the inflammatory response of islet cells with cytokine exposure.

Excellence of suito index for assessing clinical outcome of islet transplantation.

BACKGROUND: Monitoring functional islet mass after transplantation is critical to follow patients. Previously we demonstrated that the average secretory unit of islet transplant objects (SUITO) index within 1 month was an excellent predictor of insulin-free status or reduction in insulin dose. In this study, we analyzed the usefulness of daily SUITO index to assess clinical outcomes. METHODS: Five patients underwent islet transplantation, including 3 who received 2 transplantations and 2 who received a single graft. All 5 patients achieved insulin-free status with 3 remaining insulin free at the time of evaluation. We analyzed the daily relative insulin dose and SUITO index. The daily relative insulin dose was calculated as the total daily insulin dose/average pretransplant insulin dose. The SUITO index was calculated as [fasting C-peptide (ng/mL)]/[fasting blood glucose (mg/mL) - 63] x 1,500. The data analyzed based on time after islet transplantation were categorized as within or after 1 month. RESULTS: Within 1 month after islet transplantation, there was no correlation between the daily relative insulin dose and the daily SUITO index (P = .068; R = -0.33). After 1 month, the daily relative insulin dose and the daily SUITO index were strongly correlated (P < .0001; R = -0.70). When the cutoff value of the SUITO index was decided at 26 for insulin-free status, the positive predictive value was 84.1% and negative predictive value 89.4%. CONCLUSION: SUITO index was an excellent index to assess clinical outcomes beyond 1 month after islet transplantation.

Secretory unit of islet transplant objects (SUITO) index can predict outcome of intravenous glucose tolerance test.

BACKGROUND: Simple monitoring of engrafted islet function is important for follow-up of recipients after islet transplantation. We previously developed a simple assessment tool for islet graft function; the secretory unit of islet transplant objects (SUITO) index. The aim of this study was to clarify the relationship between the SUITO index and the outcomes of intravenous glucose tolerance tests (IVGTT). METHODS: Fifteen series of blood samples from 6 islet recipients were collected before 3, 5, 10, 20, and 30 minutes after injection of 0.5 g/kg 50% dextrose. The SUITO index was calculated using plasma C-peptide and glucose level at fasting baseline. Samples were divided into the following 3 groups; low-SUITO (SUITO index <10; n = 3); middle-SUITO (SUITO index > or =10 to <26; n = 4); and high-SUITO (SUITO index > or =26; n = 8). RESULTS: A threshold SUITO index of 26 showed good sensitivity (85.7%) and specificity (75.0%) to predict a blood glucose level of >10 mmol/L at 30 minutes. Blood glucose levels in the low-SUITO group were significantly higher than among the other 2 groups at baseline and 10, 20 and 30 minutes (P < .05). Glucose-level areas under the receiver-operating characteristic curve during IVGTT in the low-SUITO group were also significantly larger than among the other 2 groups (P < .05). CONCLUSION: The SUITO index, using only a fasting blood sample, predicted IVGTT outcomes.

Improved method of human islet isolation for young donors.

BACKGROUND: Although islet transplantation using young donors is more effective than older donors, islet isolation from young donor is notoriously difficult. This may relate to islet ontogeny and collagen composition in the young pancreas. Therefore, we examined whether a high concentration of collagenase could improve the separation of islets from exocrine tissues resulting in an high islet yield. METHODS: We used six human pancreata from brain-dead donors of less than 30 years old. Islet isolation was performed based on the Edmonton protocol with modifications. All pancreata were digested with Collagenase NB1 Premium Grade (Serva). The pancreas was expanded by injecting either 200 mL of cold collagenase solution (2.5 mg/mL, standard group, n = 3) or 100 mL of solution (5 mg/mL, new group, n = 3) in a controlled manner under low pressure for 5 minutes. Then the pressure was raised for another 5 minutes. The following procedure and evaluation were performed based on the Edmonton protocol. RESULTS: Phase II time in the new group was significantly shorter than the standard group. The ratio of embedded islets in the new group was significantly lower than the standard group. The postpurification islet equivalents per pancreas weight (IEQ/g) and the recovery rate in the new group were higher than the standard group, but not significantly. There was no significant difference in the postpurification purity, viability, and final tissue volume. CONCLUSION: Our simple modification with an initially concentrated collagenase preparation using a syringe significantly improved the ratio of embedded islets, resulting in a higher yield from young donors.

Induction of insulin-producing cells from human pancreatic progenitor cells.

INTRODUCTION: We previously established a mouse pancreatic stem cell line without genetic manipulation. In this study, we sought to identify and isolate human pancreatic stem/progenitor cells. We also tested whether growth factors and protein transduction of pancreatic and duodenal homeobox factor-1 (PDX-1) and BETA2/NeuroD into human pancreatic stem/progenitor cells induced insulin or pancreas-related gene expressions. MATERIALS AND METHOD: Human pancreata from brain-dead donors were used for islet isolation with the standard Ricordi technique modified by the Edmonton protocol. The cells from a duct-rich population were cultured in several media, based on those designed for mouse pancreatic or for human embryonic stem cells. To induce cell differentiation, cells were cultured for 2 weeks with exendin-4, nicotinamide, keratinocyte growth factor, PDX-1 protein, or BETA2/NeuroD protein. RESULTS: The cells in serum-free media showed morphologies similar to a mouse pancreatic stem cell line, while the cells in the medium for human embryonic stem cells formed fibroblast-like morphologies. The nucleus/cytoplasm ratios of the cells in each culture medium decreased during the culture. The cells stopped dividing after 30 days, suggesting that they had entered senescence. The cells treated with induction medium differentiated into insulin-producing cells, expressing pancreas-related genes. CONCLUSION: Duplications of cells from a duct-rich population were limited. Induction therapy with several growth factors and transduction proteins might provide a potential new strategy for induction of transplantable insulin-producing cells.

Comparison of fresh and cultured islets from human and porcine pancreata.

INTRODUCTION: For clinical islet transplantation, many centers have recently introduced of human islet cultures prior to transplantation. They provide flexibility to evaluate isolated islets and pretreat patients. However, isolated islets deteriorate rapidly in culture. In the present study, we compared fresh human and porcine islets with cultured islets for c-Jun NH(2)-terminal kinase (JNK) activity. MATERIALS AND METHODS: Islet isolations from human and porcine pancreata were performed using the standard Ricordi technique with a modified Edmonton protocol. Isolated islets cultured for 24 hours at 37 degrees C with 5% CO(2) in culture medium were evaluated for counts and JNK activity. RESULTS: After 24 hours of culture, the percentages of surviving islets were 86.9% for human and 47.3% for porcine sources. JNK activity in isolated islets declined to a low baseline level after 24-hour culture. CONCLUSION: Both human and porcine islets deteriorated rapidly in 24-hour cultures, although the in vitro conditions did not induce JNK activation.

Super-high-dose islet transplantation is associated with high SUITO index and prolonged insulin independence: a case report.

INTRODUCTION: One of the current issues of clinical islet transplantation is the difficulty to achieve a prolonged insulin-free status. Functional islet mass gradually decreased after transplantation. We developed the SUITO index, which reflects engrafted islet mass. The SUITO (Secretory Unit of Islet Transplant Objects) index more than 26.0 is associated with an insulin-free status. In this study, we have experienced that super-high-dose islet transplantation maintained insulin-free status and a high SUITO index for a prolonged period. MATERIALS AND METHODS: Two islet isolations were performed in February 2007 and January 2008. Ductal injections were performed at the procurement site using the ET-Kyoto solution and pancreata preserved by a two-layer method. Islets were isolated using the modified Ricordi method. Both isolated islets were transplanted into a type 1 diabetic patient. Efficacy of islet transplantation was assessed by the amount of insulin requirements and SUITO index. RESULTS: Islet yields were 514,467 islet equivalents (IE) and 872,174 IE, with purities of 49% and 85% for the first and second islet transplantations, respectively. The patient received a total of 24,327 IE/kg body weight. The immunosuppression was based on the Edmonton protocol. After the second islet transplantation, the average SUITO index for the following 1 month was 48.5, and the patient became insulin-free. At postoperative day 1006, the SUITO index was 44.6 and the patient maintained an insulin-free status with excellent glycemic control. CONCLUSION: Super-high-dose islet transplantation was associated with an high SUITO index and prolonged insulin independence.

ET-Kyoto ductal injection and density-adjusted purification combined with potent anti-inflammatory strategy facilitated single-donor islet transplantation: case reports.

BACKGROUND: The necessity to use multiple donors for achieving insulin independence in clinical islet transplantation is still a major issue. We have developed a modified islet isolation method for non-heart-beating donors (Kyoto method) to significantly increase islet yield. In this study, we further modified the method for brain-dead donors and in addition, introduced a potent anti-inflammatory strategy aiming for single-donor islet transplantation. MATERIALS AND METHODS: Two islet isolations used pancreatic ductal preservation with the modified Kyoto solution and a density-adjusted purification method. Anti-interleukin-1-beta antibody (Anakinra) and anti-tumor necrosis factor-alpha (Eternacept) were administered during and after transplantation. The efficacy of the islet transplantation was assessed by the insulin requirement and SUITO (Secretory Unit of Islet Transplant Objects) index, wherein a value of more than 26.0 seems to be associated with insulin independence. RESULTS: Both isolated islet preparations met the criteria for transplantation. They were transplanted into two type 1 diabetic patients, both of whom became insulin independent with stable glycemic control. The average SUITO index within 1 month was 29.2 and 45.3. CONCLUSION: The islet isolation method combined with a potent anti-inflammation strategy made it possible to achieve single-donor islet transplantation achieving a high SUITO index.

Evaluation of engraftment after single islet transplantation from a brain-dead donor by the secretory unit of islet transplant objects (SUITO) index.

BACKGROUND: Evaluation of engraftment is important to assess the success of islet transplantation. Recently, we developed a simple index of islet engraftment, the secretory unit of islet transplant objects (SUITO) index. The formula is: 1500 x fasting C-peptide level [ng/dL]/(fasting blood glucose levels [mg/dL]-63). A SUITO index of more than 26 was associated with insulin independence. MATERIALS AND METHODS: In this study, we compared islet engraftment efficacy using the SUITO index after a single infusion of islets from brain-dead donors into 6 recipients. We calculated the SUITO index from postoperative days 3 to 30. We compared the insulin reduction rate with the SUITO index and islet equivalent per kilogram body weight (IE/Kg). We also measured the level of glycosylated hemoglobin (HbA 1C) at 3 months posttransplantation to assess glycemic control after islet transplantation. RESULTS: In 5 cases, islets were cultured before transplantation and in 1 case they were transplanted without culture. Without culture, the SUITO index and insulin reduction rate were highest. The SUITO index significantly correlated with the insulin reduction rate (P = .031, R2 = .728), but the IE/kg was not significantly correlated (P = .303) with the rate of insulin reduction. All cases showed improved HbA 1C to the normal range. CONCLUSIONS: Immediate transplantation without culture substantially improved the efficacy of engraftment of transplanted islets. The SUITO index was a better predictor than islet mass per body weight for clinical outcomes.

Estimation of donor usability for islet isolation with the modified Ricordi method.

BACKGROUND: The quality of donor pancreata is important for successful islet isolation. However, in some countries like Japan, the number of donor pancreata is low. Therefore, marginal donor pancreata have been used with less restrictive donor criteria. In order to use marginal donor pancreata, we established the modified Ricordi method. According to the United Network for Organ Sharing (UNOS) in 2005, more than 6000 pancreata were not clinically usable in the United States. In this study, we reevaluated donor usability based on the Japanese islet donor criteria. MATERIALS AND METHODS: We reviewed donor charts with well-documented cases in Texas from 2005 to 2006. We counted the number of pancreata for pancreas transplantation or islet transplantation. If not used clinically, the reason was also reviewed. Donors were reevaluated based on the Japanese islet donor criteria. RESULTS: We reviewed 236 donor charts, including 29 pancreata used for whole pancreas transplantations and 13 for islet isolation; therefore, 194 pancreata were not used. Among the 194 cases, we were able to identify the reasons that the pancreata were not used in 186 cases. When we applied the Japanese acceptance criteria, an additional 82 of 186 cases (44%) seemed suitable for islet isolations. CONCLUSIONS: With the modified Ricordi method, more than 2500 donor pancreata might be used for islet isolation in the United States when the Japanese criteria are applied.

Effect of JNK inhibitor during islet isolation and transplantation.

Although islet transplantation has been remarkably improved by the Edmonton protocol, the insulin independence rate after islet transplantation from one donor pancreas has remained low. The c-Jun NH2-terminal kinases (JNKs) are classic stress-activated protein kinases; many cellular stresses have been shown to stimulate JNK activation. JNK in the pancreas is activated during brain death, pancreas procurement, and organ preservation, and its activity is progressively increased during the isolation procedure. Moreover, JNK activity in the transplanted liver after islet transplantation increases markedly within 24 hours. In this study, we show the effect of a JNK inhibitor during islet isolation and transplantation. Use of the JNK inhibitor in pancreas preservation, islet culture, and/or islet transplantation prevents islet cell apoptosis and improves islet graft function. These findings suggest that inhibition of JNK could prevent the impairment of islet cells and improve outcomes after pancreatic islet transplantation.