Islet cell transplantation for the treatment of type 1 diabetes in the USA

Targeted delivery of harmine to xenografted human pancreatic islets promotes robust cell proliferation

Type 1 diabetes (T1D) occurs as a consequence of the autoimmune destruction of insulin-producing pancreatic beta (β) cells and commonly presents with insulin deficiency and unregulated glycemic control. Despite improvements in the medical management of T1D, life-threatening complications are still common. Beta-cell replication to replace lost cells may be achieved by using small-molecule mitogenic drugs, like harmine. However, the safe and effective delivery of such drugs to beta cells remains a challenge. This work aims to deploy an antibody conjugated nanocarrier platform to achieve cell-specific delivery of candidate therapeutic and imaging agents to pancreatic endocrine cells. We approached this goal by generating core-shell type micellar nanocarriers composed of the tri-block copolymer, Pluronic®F127 (PEO₁₀₀-PPO₆₅-PEO₁₀₀). We decorated these nanocarriers with a pancreatic endocrine cell-selective monoclonal antibody (HPi1), with preference for beta cells, to achieve active targeting. The PPO-based hydrophobic core allows encapsulation of various hydrophobic cargoes, whereas the PEO-based hydrophilic shell curbs the protein adhesion, hence prolonging the nanocarriers' systemic circulation time. The nancarriers were loaded with quantum dots (QDots) that allowed nanocarrier detection both in-vitro and in-vivo. In-vitro studies revealed that HPi1 conjugated nanocarriers could target endocrine cells in dispersed islet cell preparations with a high degree of specificity, with beta cells exhibiting a fluorescent quantum dot signal that was approximately five orders of magnitude greater than the signal associated with alpha cells. In vivo endocrine cell targeting studies demonstrated that the HPi1 conjugated nanocarriers could significantly accumulate at the islet xenograft site. For drug delivery studies, the nanocarriers were loaded with harmine. We demonstrated that HPi1 conjugated nanocarriers successfully targeted and delivered harmine to human endocrine cells in a human islet xenograft model. In this model, targeted harmine delivery yielded an ~ 41-fold increase in the number of BrdU positive cells in the human islet xenograft than that observed in untreated control mice. By contrast, non-targeted harmine yielded an ~ 9-fold increase in BrdU positive cells. We conclude that the nanocarrier platform enabled cell-selective targeting of xenografted human pancreatic endocrine cells and the selective delivery of the hydrophobic drug harmine to those cells. Further, the dramatic increase in proliferation with targeted harmine, a likely consequence of achieving higher local drug concentrations, supports the concept that targeted drug delivery may promote more potent biological responses when using harmine and/or other drugs than non-targeting approaches. These results suggest that this targeted drug delivery platform may apply in drug screening, beta cell regenerative therapies, and/or diagnostic imaging in patients with type 1 diabetes.

Adipose Tissue From Type 1 Diabetes Mellitus Patients Can Be Used to Generate Insulin-Producing Cells

OBJECTIVES

We aimed to determine whether responsive insulin-producing cells (IPCs) could be generated from adipose-derived stem cells (ADSCs) isolated from patients with type 1 diabetes mellitus (T1DM).

METHODS

We isolated ADSCs from adipose tissue of 4 patients (one patient with T1DM and 3 nondiabetic patients), who underwent surgery and differentiated them into IPCs with using a 2-step xeno-antigen free, 3-dimensional culture method. Characteristics of isolated ADSCs, in vitro cell quality, programmed cell death ligand-1 (PDL-1) expression, and transplantation into streptozotocin induced diabetic nude mice were investigated.

RESULTS

Adipose-derived stem cells from T1DM patients and commercially obtained ADSCs showed the same surface markers; CD31CD34CD45CD90CD105CD146. Moreover, the generated IPCs at day 21 demonstrated appropriate autonomous insulin secretion (stimulation index, 3.5; standard deviation, 0.8). Nonfasting blood glucose concentrations of IPC-transplanted mice were normal at 30 days. The normalized rate of IPC-transplanted mice was significantly higher than that of the sham-operated group (P < 0.05). Insulin-producing cells generated from T1DM adipose tissue expressed high levels of PDL-1.

CONCLUSIONS

Insulin-producing cells obtained from adipose tissue of T1DM patients are capable of secreting insulin long-term and achieve normoglycemia after transplantation. Expression of PDL-1 suggests the potential for immune circumvention.

In vitro and in vivo effects of insulin-producing cells generated by xeno-antigen free 3D culture with RCP piece

To establish widespread cell therapy for type 1 diabetes mellitus, we aimed to develop an effective protocol for generating insulin-producing cells (IPCs) from adipose-derived stem cells (ADSCs). We established a 3D culture using a human recombinant peptide (RCP) petaloid μ-piece with xeno-antigen free reagents. Briefly, we employed our two-step protocol to differentiate ADSCs in 96-well dishes and cultured cells in xeno-antigen free reagents with 0.1 mg/mL RCP μ-piece for 7 days (step 1), followed by addition of histone deacetylase inhibitor for 14 days (step 2). Generated IPCs were strongly stained with dithizone, anti-insulin antibody at day 21, and microstructures resembling insulin secretory granules were detected by electron microscopy. Glucose stimulation index (maximum value, 4.9) and MAFA mRNA expression were significantly higher in 3D cultured cells compared with conventionally cultured cells (P < 0.01 and P < 0.05, respectively). The hyperglycaemic state of streptozotocin-induced diabetic nude mice converted to normoglycaemic state around 14 days after transplantation of 96 IPCs under kidney capsule or intra-mesentery. Histological evaluation revealed that insulin and C-peptide positive structures existed at day 120. Our established xeno-antigen free and RCP petaloid μ-piece 3D culture method for generating IPCs may be suitable for clinical application, due to the proven effectiveness in vitro and in vivo.

A New 2-Step Acceleration Protocol Using a Histone Deacetylase Inhibitor to Generate Insulin-Producing Cells From Adipose-Derived Mesenchymal Stem Cells

OBJECTIVES

We aimed to develop a simple protocol for deriving insulin-producing cells (IPCs) from adipose-derived mesenchymal stem cells (ADSCs). We established a 2-step creation method and an acceleration strategy with a histone deacetylase inhibitor that promoted a pro-endocrine pancreatic lineage.

METHODS

We seeded ADSCs in 96-well dishes and cultured in Dulbecco's modified Eagle's medium/F12 medium containing 1% fetal bovine serum, 1% B27 supplement, 1% N2 supplement, 50-ng/mL human activin A, and 10-nM exendin-4 for step 1 of differentiation (7 days). Then 10-mM nicotinamide and 50-ng/mL human hepatocyte growth factor, with or without 1 mM histone deacetylase inhibitor, were added for step 2 of differentiation (14 days). After the 2-step differentiation was complete, cell morphology, immunohistochemistry, messenger RNA expression, and function were investigated.

RESULTS

Our new differentiation protocol with the histone deacetylase inhibitor significantly accelerated IPC differentiation compared with the conventional protocol without the histone deacetylase inhibitor (median, 21.6 vs 38.8 days; P < 0.05). It also improved the islet morphology score (P < 0.05) and the glucose stimulation index (3.1).

CONCLUSIONS

By applying our new and easy 2-step protocol using a histone deacetylase inhibitor, ADSCs may be an effective cell source for differentiation of IPCs.

Effect of the Duration of Chronic Pancreatitis on Pancreas Islet Yield and Metabolic Outcome Following Islet Autotransplantation

BACKGROUND

Total pancreatectomy (TP) with islet autotransplantation (IAT) is a highly selected treatment for severe pain associated with chronic pancreatitis (CP) after exhausting medical and endoscopic therapies. The effect of duration of CP on TP-IAT has not been clarified.

METHODS

Retrospective review of a consecutive cohort undergoing TP-IAT was performed. Patients were classified according to islet dose of <2500 IEQ/kg, 2500 to 5000 IEQ/kg, and >5000 IEQ/kg. Islet yield and metabolic outcomes were compared to disease duration of CP.

RESULTS

A total of 76 CP patients underwent TP-IAT. Longer disease duration was associated with lower islet yield transplanted (Spearman's correlation = -0.24; p = 0.04) for total cohort. Highest absolute value of the coefficient was found in patients with hereditary CP when study subjects were classified by the etiology of CP (correlation = -0.72; p = 0.02). Higher islet yields were significantly associated with better metabolic outcomes (7.6 ± 1.1 vs 6.6 ± 1.1% of HbA1c post-TPIAT in patients with <2500 and >5000 IEQ/kg transplanted, respectively; p = 0.04).

CONCLUSIONS

The duration of CP could affect islet yield and metabolic outcomes. The time since the diagnosis of CP should be considered when selecting patients for islet autotransplantation.

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.

A new method for generating insulin-secreting cells from human pancreatic epithelial cells after islet isolation transformed by NeuroD1

The generation of insulin-secreting cells from nonendocrine pancreatic epithelial cells (NEPEC) has been demonstrated for potential clinical use in the treatment of diabetes. However, previous methods either had limited efficacy or required viral vectors, which hinder clinical application. In this study, we aimed to establish an efficient method of insulin-secreting cell generation from NEPEC without viral vectors. We used nonislet fractions from both research-grade human pancreata from brain-dead donors and clinical pancreata after total pancreatectomy with autologous islet transplantation to treat chronic pancreatitis. It is of note that a few islets could be mingled in the nonislet fractions, but their influence could be limited. The NeuroD1 gene was induced into NEPEC using an effective triple lipofection method without viral vectors to generate insulin-secreting cells. The differentiation was promoted by adding a growth factor cocktail into the culture medium. Using the research-grade human pancreata, the effective method showed high efficacy in the differentiation of NEPEC into insulin-positive cells that secreted insulin in response to a glucose challenge and improved diabetes after being transplanted into diabetic athymic mice. Using the clinical pancreata, similar efficacy was obtained, even though those pancreata suffered chronic pancreatitis. In conclusion, our effective differentiation protocol with triple lipofection method enabled us to achieve very efficient insulin-secreting cell generation from human NEPEC without viral vectors. This method offers the potential for supplemental insulin-secreting cell transplantation for both allogeneic and autologous islet transplantation.

Trophic effect of adipose tissue-derived stem cells on porcine islet cells

BACKGROUND

Adipose tissue-derived stem cells (ADSCs), which are widely known as multipotent progenitor cells, release several cytokines that support cell survival and repair. The aim of this study was to investigate whether ADSC-secreted molecules could induce a trophic effect in pancreatic islet culture conditions in vitro.

MATERIALS AND METHODS

We cocultured porcine islet cells with ADSCs using a transwell system for 48 h and evaluated the viability of islet cells. We also determined the concentration levels of cytokines and insulin in the supernatant of the culture medium. We used anti-vascular endothelial growth factor (VEGF) and anti-interleukin (IL)-6 receptor antibodies to investigate the effect of VEGF and IL-6 on islet cells.

RESULTS

ADSCs improved the viability of islet cells in the absence of cell-cell contact (P < 0.05). VEGF and IL-6 levels in the culture medium increased when islet cells were cocultured with ADSCs (P < 0.05). Furthermore, inhibition of VEGF decreased the viability of islet cells (P < 0.05); however, inhibition of IL-6 did not affect islet cell viability.

CONCLUSIONS

These results suggested that trophic factors, particularly VEGF, secreted by human ADSCs enhanced the survival and function of porcine islet cells.

Effects of astragalosides on cultured islets after cryopreservation in rats

OBJECTIVE

To explore the effects of AST (astragalosides) on cultured rat islet yield, purity, and function after cryopreservation in rats.

METHODS

Pancreatic islets were isolated from 30 Sprague-Dawley rats using the standard technique of collagenase P digestion and discontinuous Ficoll gradient purification. After thaw, the islets were randomly divided into AST group and control group (n=15). Next, the islet cells were cultured in AST-containing medium or standard medium for 7, 14, and 21 days after cryopreservation and thaw. The quantity, purity, and survival rate were calculated in the two groups before and after culture. Then the in vitro and in vivo function was observed in diabetic rats after islet transplantation.

RESULTS

The quantity and purity of islets had no difference between the two groups before culture (P>.05) while the difference after culture was significantly (P<.05). The survival rate of islets was 48% in AST group and 32% in the control group 21 days after thaw (P<.05). After 3 days, there was significantly a higher simulation index in the AST group than in the control group (P<.05). There was a significant difference in blood glucose and insulin concentrations between the groups after 3 days (P<.05).

CONCLUSION

AST can be added to the culture medium to reduce the loss of islet cryopreservation and be intravenously injected to improve culture islet function in vitro and prolong islet graft survival in diabetic rats.

Adverse events in clinical islet transplantation: one institutional experience

Islet transplantation is one of the most promising treatments for an unstable form of type 1 diabetes. However, islet transplantation still has some obstacles, such as low success rate of islet isolation, difficulty to obtain long-term insulin freedom, and adverse events related to transplant protocol. We describe the adverse events of current clinical islet transplantation at our institute in this report. Nine type 1 diabetic patients received 17 islet infusions from March 2005 to October 2008. The islet infusion procedure and immunosuppression regimen were based on a modified Edmonton protocol. Severe adverse events (SAEs) were defined as events that were more than grade 3 according to the Terminology Criteria for Adverse Events in Trials of Adult Pancreatic Islet Transplantation, version 4.1 (Collaborative Islet Transplant Registry, CITR). Sixteen events were reported as SAEs and among them 12 events were probably or definitely related to transplant protocols; all occurred within 1 year after infusion except for one. Five adverse events (31%) occurred within 10 days after transplantation and were related to infusion procedures. Seven events (44%) occurred after 50 days and were related to immunosuppressive therapy. SAEs related to the protocol included three events of elevated liver enzymes, two of hemorrhage into gall bladder or peritoneal cavity, two of neutropenia, two of infection, one of vomiting, one of diarrhea, and one of renal dysfunction. All events were grade 3, except for one case that was grade 4 of neutropenia. All SAEs resolved with no sequelae. Neoplasms and deaths were not observed in our study. The present study suggests need to improve both infusion procedure and immunosuppressive strategy from the view of preventing SAEs.

Japanese herbal medicine TJ-48 prevents autoimmune diabetes in NOD mice

Type 1 diabetes mellitus (T1DM) is mainly caused by CD8(+) cytotoxic T cell infiltration into islets. Recently, the role of regulatory T cells (Tregs) in the prevention of the onset of T1DM was reported. We reported that TJ-48, a common Japanese herbal medicine, decreased Treg population in cancer patients, thus we investigated whether TJ-48 had an influence on T1DM onset using NOD mice. In the TJ-48 group, TJ-48 (2.0g/kg/day) was administered in the drinking water for NOD mice from three weeks of age to 20 weeks of age. Their body weight and fast blood glucose (FBG) were measured every week. Histology (Hematoxylin-Eosin staining) was investigated every month. Lymphocyte profiles were investigated every month with FACS. The results were compared to the age-matched NOD mice control group. FBG of the control group mice showed diabetic status of 66.7% at 18 weeks of age. On the other hand, the TJ-48 group mice showed diabetic status of 16.7% at 18 weeks of age (p = 1.905E-06). There were no significant differences in general conditions or body weight between the two groups. Lymphocyte infiltrations into islets were dramatically suppressed in the TJ-48 group. The effect of TJ-48 on decreasing Tregs was less apparent in the NOD mice model. TJ-48 inhibited lymphocyte infiltrations into islets, which led to preventing the onset of T1DM in NOD mice.

Recent progress in pancreatic islet transplantation

Diabetes mellitus remains a major burden. More than 200 million people are affected worldwide, which represents 6% of the world’s population. Type 1 diabetes mellitus is an autoimmune disease, which induces the permanent destruction of the β-cells of the pancreatic islets of Langerhans. Although intensive insulin therapy has proven effective to delay and sometimes prevent the progression of complications such as nephropathy, neuropathy or retinopathy, it is difficult to achieve and maintain long term in most subjects. The successes achieved over the last few decades by the transplantation of whole pancreas and isolated islets suggest that diabetes can be cured by the replenishment of deficient β cells. However, islet transplantation efforts have various limitations, including the limited supply of donor pancreata, the paucity of experienced islet isolation teams, side effects of immunosuppressants and poor long term results. The purpose of this article is to review the recent progress in clinical islet transplantation for the treatment of diabetes and to describe the recent progress on pancreatic stem/progenitor cell research, which has opened up several possibilities for the development of new treatments for diabetes.

Pancreatic islets from non-heart-beating donor pig: two-layer preservation method in an in vitro porcine model

PURPOSE

Pancreata from non-heart beating donors could represent an unlimited source of islets if their cell viability can be efficiently preserved during the time necessary to process the organs by the use of a better solution of preservation compared to the classic University of Wisconsin solution. The aim of this study was to determine whether it is possible to obtain functioning "alive islets" from non-heart-beating donors by comparing, on a porcine model, the classic "UW ice-store" method with a two-layer cold storage method (TLM) using oxygenated Perfluorocarbons (PFC) and UW.

METHODS

Whole pancreata were harvested from 20 NHBDs female pigs with similar characteristics and preserved for 4 h in UW solution (n = 10) or TLM (UW/PFC) solution (n=10). The isolated islets were then evaluated for number, viability, purity, and insulin secretion, also estimated after 8 weeks of cryopreservation.

RESULTS

The total number of islets obtained from isolation, and their function assayed by the insulin stimulation index, before and after cryopreservation, showed a higher value in the TLM group. No significative differences in terms of purity and viability before and after cryopreservation were found when comparing the two groups.

CONCLUSIONS

TLM solution for NHBDs porcine pancreata with cold ischemia time lower than 4 h offers significant advantages over UW solution storage, thereby increasing the isolation yield and isolation success rate of the pancreatic porcine islets.

Variables associated with islet yield in autologous islet cell transplantation for chronic pancreatitis

The goal of total pancreatectomy followed by autologous islet cell transplantation is to manage pain and prevent surgical diabetes for patients with severe chronic pancreatitis. We performed this procedure in 17 patients from November 2006 to October 2009 at Baylor University Medical Center. All patients were included in this retrospective study and were divided into two groups based on islet yield in the final product based on patient body weight: a low-yield group (<5000 IE/kg) and a high-yield group (>/=5000 IE/kg). There were significant differences between the two groups in the rate of pancreatic findings on computed tomography (low vs high group, 88% vs 22%: P = 0.02), Cambridge classification score for endoscopic retrograde cholangiopancreatography (3.8 +/- 0.2 vs 2.1 +/- 0.6: P = 0.03), number of positive endoscopic ultrasonography criteria (6.0 +/- 0.8 vs 3.5 +/- 0.4: P = 0.04), and distension score (1.9 +/- 0.4 vs 3.7 +/- 0.2: P = 0.006). A significant reduction in narcotics use after the operation was observed in both groups (P = 0.03 and P = 0.009 in the low and high groups, respectively, using a paired t test). Excellent graft function and glycemic control after the transplantation were also demonstrated in both groups. Patients in the high-yield group were in the early stage of chronic pancreatitis, which led to excellent pancreatic distention for islet isolation; however, the excellent clinical outcomes were observed in both low- and high-yield groups.

Whole-organ pancreas transplantation at Baylor Regional Transplant Institute: a chance to cure diabetes

The success of pancreas transplantation has improved over the past several decades with advancements in surgical technique, immunosuppressive medicines, and immunologic testing. We retrospectively reviewed our experience with pancreas transplantation from 1995 to 2008. At the Baylor Regional Transplant Program, 151 pancreas transplants were performed in 147 patients: 135 were simultaneous pancreas-kidney transplants, 10 were pancreas transplants after kidney transplants, and 6 were pancreas transplants alone. Follow-up information was available for 138 patients. The 1-year acute cellular rejection rate was 31.6%; the 30-day surgical reexploration rate was 10%; and the technical failure rate was 5.3%. Five-year pancreas graft survival rates were 67% for simultaneous pancreas and kidney transplants and 50% for pancreas transplants after kidney transplants. These outcomes exceed expected results as calculated by the Scientific Registry of Transplant Recipients. In addition, the median time to transplant was 3.8 months, compared with a US median of 14.1 months. Pancreas transplantation is currently the closest thing to a cure for diabetes and should be given as an option for diabetic patients with or without end-stage renal disease.

Secretory unit of islet transplant objects (SUITO) index can predict severity of hypoglycemic episodes in clinical islet cell transplantation

One endpoint of clinical islet cell transplantation for type 1 diabetic patients is the elimination or reduction of hypoglycemia. We previously developed a simple tool to evaluate islet graft function: the secretory unit of islet transplant objects (SUITO) index. The aim of this study is to clarify the association between the SUITO index and hypoglycemic episodes. Data from 310 clinical evaluations of 11 islet recipients were included in this study. Fasting plasma C-peptide and glucose levels were measured at every evaluation. The SUITO index was calculated according to the following formula: 1500 × C-peptide level (ng/ml)/[blood glucose level (mg/dl) - 63]. The number of hypoglycemic events (<3.8 mmol/L) and severe hypoglycemic events (<2.2 mmol/L or hypoglycemic unawareness) was assessed on the basis of interviews and self-monitoring of blood glucose (SMBG). Receiver operating characteristic (ROC) analysis was performed to determine the cut-off values of the SUITO index for hypoglycemic events. Based on the ROC study, follow-up data after transplantations were divided into the following three groups: low-SUITO (SUITO index <10, n = 91), middle-SUITO (10 ≤SUITO index <26, n = 83), high-SUITO (SUITO index ≤26, n = 125). The frequency of total hypoglycemia in the high-SUITO group was significantly decreased when compared to the other groups (value with Kruskal-Wallis test p < 0.001). The frequency of total severe hypoglycemia was significantly decreased in the low-SUITO group compared to pretransplant status and further decreased in the middle- and high-SUITO group. Spearman correlation coefficients were -0.663 (p < 0.001) between the number of total hypoglycemic events per one month and the SUITO index and -0.521 (p < 0.001) between that of severe events and the SUITO index. The SUITO index could predict the severity of hypoglycemic episodes in type 1 diabetic patients who received islet cell transplantations.

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.

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.

Neurogenic differentiation 1 directs differentiation of cytokeratin 19-positive human pancreatic nonendocrine cells into insulin-producing cells

BACKGROUND

It has been reported that the human pancreatic nonendocrine fraction, which remains after islet isolation, can be differentiated toward beta cells. However, the optimal method to accomplish this goal has not been established. In this study, we introduced the human neurogenic differentiation 1 (NeuroD1) gene into human nonendocrine pancreatic epithelial cells (NEPECs) and promoted insulin-producing cells in vitro.

METHODS

The human pancreatic nonislet fractions were obtained from brain-dead donors and cultured in suspension for 2-3 days followed by culture with G418 for 4 days. These cells (NEPECs) were then plated on dishes. The NEPECs spread into a cell monolayer within 7 days and all of the cells were cytokeratin-19 (CK19) positive. Seven days after plating, plasmids encoding human NeuroD1 gene under human CK19 promoter were transfected 3 times every other day (termed NEPEC+ND). Seven days after starting induction, these cells were characterized.

RESULTS

Seven days after starting the induction of human NeuroD1, NEPEC+ND strongly expressed NeuroD1 and insulin mRNA. The ratio of NeuroD1-positive cells in NEPEC+ND was significantly higher than in NEPEC. Human insulin-positive cells in NEPEC+ND were also significantly greater than in NEPEC. Human insulin and C-peptide levels in culture medium in NEPEC+ND were significantly higher than in NEPEC.

CONCLUSIONS

These findings demonstrated that human NeuroD1 under control of the CK19 promoter can induce the differentiation of CK19-positive NEPECs into insulin-producing cells.

Implication of pancreatic image findings in total pancreatectomy with islet autotransplantation for chronic pancreatitis

OBJECTIVE

To clarify the implication of pancreatic findings on transabdominal ultrasound and/or abdominal computed tomographic scan on outcomes of islet isolation and endocrine function after total pancreatectomy (TP) with islet autotransplantation (IAT).

METHODS

Retrospective review of islet isolations and graft functions in a cohort of patients with chronic pancreatitis who received TP with IAT from December 2007 to September 2009. Patients were categorized into the following 2 groups on the basis of their transabdominal ultrasound or computed tomographic findings before IAT: early group (normal or equivocal of Cambridge classification) and advanced group (mild to marked).

RESULTS

A total of 12 patients (early group, n=6; advanced group, n=6) were included. Total islet yield per pancreas weight and per patient body weight in the early group was significantly higher compared with that in the advanced group (6989±659 vs 3567±615 islet equivalents per gram, P<0.01; 8556±953 vs 3847±739 islet equivalents per kilogram, P<0.01, respectively). Four patients (67%) in the early group became insulin-free, whereas 2 patients (33%) in the advanced group obtained insulin independence. However, both groups maintained islet graft function and similar glycated hemoglobin levels after transplantation.

CONCLUSIONS

Excellent glycemic control was observed in both groups of patients who received TP with IAT, although the early group showed a significantly better outcome of islet isolation.

Human adipose-derived stem cells: potential clinical applications in surgery

Regenerative medicine is emerging as a rapidly evolving field of research and therapeutics. Stem cells hold great promise for future translational research and clinical applications in many fields. Much research has focused on mesenchymal stem cells isolated from bone marrow in vitro and in vivo; however, bone marrow procurement causes considerable discomfort to the patient and yields a relatively small number of harvested cells. By contrast, adipose tissue represents an abundant and easily accessible source of adult stem cells, termed adipose-derived stem cells (ADSCs), with the ability to equally differentiate along multiple lineage pathways. These stem cells have angiogenic properties, possibly because of their secretion of cytokines. They may also play a role in healing acute and chronic tissue damage. Subsequently, they have a wide range of potential clinical implications. This article reviews the potential preclinical and clinical applications of mesenchymal stem cells, especially ADSCs, in surgery.

Superiority of visipaque (iodixanol)-controlled density gradient over Ficoll-400 in adult porcine islet purification

OBJECTIVE

Sufficient and favorable biological functions of islets are major problems hindering xenotransplantation. The aim of the present study was to evaluate the effects on harvesting, purity, viability, and function of using improved Visipaque (iodixanol) and Ficoll-400 for adult porcine islet purification.

METHODS

Twelve adult porcine pancreata were randomly divided into an Iodixanol-University of Wisconsin (UW) group and a Ficoll-400-UW group according to the purification method. Porcine pancreata were isolated by collagenase digestion. After isolation and purification, the islet yield and purity were evaluated by dithizone staining, and islet function assessed by in vitro insulin release assays and in vivo islet xenotransplantation.

RESULTS

There were no marked differences in the islet yield before purification (5254.67 +/- 189.44 IEQ/g vs 5092.67 +/- 178.94 IEQ/g, P > .05). After purification, there were significantly more islets harvested in Iodixanol-UW group than in the Ficoll-400-UW group: 4222.00 +/- 228.84 IEQ/g vs 3036.83 +/- 79.60 IEQ/g (P < .05). Islets from the two groups showed satisfactory insulin secretory ability. There were no significant differences in islet survival times between the two groups in diabetic rats: 8.2 +/- 1.619 days vs 6.9 +/- 1.197 days (P > .05).

CONCLUSION

The improved iodixanol-UW density gradient method was superior to Ficoll-400 method to improve the number, viability, and insulin secret of purified adult porcine islets although the benefits did not improve in vivo survival.

New stepwise cooling system for short-term porcine islet preservation

OBJECTIVES

Porcine islets are the most suitable for xeno-islet transplantation. However, it is necessary to establish an effective preservation method against its fragility. Recently, we developed a new cooling and preservation (Keep and Fresh [KFC]; FUJIYA Co, Tokushima, Japan) system, which can maintain viability of hepatocyte. In this study, we examined the KFC for porcine islet preservation.

METHODS

Isolated porcine islets were preserved in CMRL 1066 culture media with bovine serum at 37°C, 22°C, and 4°C and KFC for 24, 48, and 72 hours. Islet recovery rate, purity, and viability were evaluated.

RESULTS

After 24-hour preservation, the recovery rate was the highest in the KFC, but no significant difference was found. After 48-hour preservation, the recovery rate by the KFC was 73.9% ± 17.3%, which was significantly higher than the other groups (48.7% ± 28.6% at 37°C, P < 0.01; 46.6% ± 15.5% at 22°C, P < 0.01; 61.5% ± 20.0% at 4°C, P < 0.05). After 72-hour preservation, the difference of recovery rate was clearer. In the KFC group, purities and viabilities were the highest among the groups after 24-, 48-, and 72-hour preservation.

CONCLUSIONS

The KFC system significantly improved porcine islet preservation; therefore, the KFC might be useful for porcine islet preservation.

Body mass index reflects islet isolation outcome in islet autotransplantation for patients with chronic pancreatitis

Total pancreatectomy with autologous islet cell transplantation (TP with AIT) is an effective treatment for chronic pancreatitis patients with severe abdominal pain. Body mass index (BMI) of the pancreatic donor is proven to be a useful predictor for islet isolation and transplantation outcomes in allogenic islet transplantation. However, the association between BMI and islet isolation outcome and/or metabolism after AIT was previously unclear. Twelve patients who received TP with AIT at our hospital were included in this study. All pancreata were preserved with both pancreatic ductal injection and oxygen-charged static two-layer method using ET-Kyoto solution. The cohort was divided into two groups: low BMI group (BMI <23 kg/m(2), n=5) and high BMI group (BMI ≥23, n=7). The high BMI group had a significantly higher islet yield per gram than the low BMI group both in pancreas postdigestion and in final product (postdigestion: 7330 ± 539 vs. 3509 ± 563 IE/g; p<0.001; final product: 6555 ± 585 vs. 3476 ± 546 IE/g; p=0.004). For islet yield in final product per patient body weight, the high BMI group also had significantly higher islet yield than the low BMI group (7997 ± 779 vs. 4175 ± 750 IE/kg, p=0.007). Insulin independence rate in the high BMI group (71%) was also higher than that low BMI group (40%), but it did not reach statistical significance. Pancreata from patients with higher BMI could obtain higher islet yield in the setting of autologous islet cell transplantation for chronic pancreatitis.

Assessment of islet quality following international shipping of more than 10,000 km

Islet transplantation is an attractive therapy for type 1 diabetes, although some issues remain. One of them is the severe donor shortage in some countries. In this study, we investigated the possibility of international islet shipping beyond 10,000 km to supply islets to countries with donor shortages. Human islets were isolated from six cadaver donors and cultured until shipment. Islets were packed in either gas-permeable bags or in non-gas-permeable bags and shipped from Baylor Research Institute (Dallas, TX, USA) to Fukuoka University (Fukuoka, Japan). Pre- and postshipment islet number, purity, viability, and stimulation index (by glucose stimulation test) were assessed. Shipped 1,500 IE islets were transplanted into streptozotocin-induced diabetic nude mice for in vivo assay. The distance of our shipment was 11,148.4 km, and the mean duration of the shipments was 48.2 ± 8.2 h. The islet number recovery rate (postshipment/preshipment) was significantly higher in gas-permeable bags (56.4 ± 10.1% vs. 20.5 ± 20.6%, p < 0.01). Islet purity was significantly reduced during shipment in non-gas-permeable bags (from 47.7 ± 18.6% to 40.2 ± 28.2 in gas-permeable bags vs. from 50.4 ± 6.4% to 25.9 ± 15.6% in non-gas-permeable bags, p < 0.05). Islet viability and stimulation index did not change significantly between pre- and postshipping, in either gas-permeable bags or in non-gas-permeable bags. One of three diabetic nude mice (33.3%) converted to normoglycemia. It is feasible to ship human islet cells internationally in gas-permeable bags. This strategy would promote basic and preclinical research for countries with donor shortages, even though the research centers are remote (over 10,000 km from the islet isolation center).