Pancreas-kidney and pancreas transplantation for the treatment of diabetes mellitus

Surgical complications after pancreatic transplantation: A computed tomography imaging pictorial review

Pancreatic transplantation is considered by the American Diabetes Association and the European Association for the Study of Diabetes an acceptable surgical procedure in patients with type 1 diabetes also undergoing kidney transplantation in pre-final or end-stage renal disease if no contraindications are present. Pancreatic transplantation, however, is a complex surgical procedure and may lead to a range of postoperative complications that can significantly impact graft function and patient outcomes. Postoperative computed tomography (CT) is often adopted to evaluate perfusion of the transplanted pancreas, identify complications and as a guide for interventional radiology procedures. CT assessment after pancreatic transplantation should start with the evaluation of the arterial Y-graft, the venous anastomosis and the duodenojejunostomy. With regard to complications, CT allows for the identification of vascular complications, such as thrombosis or stenosis of blood vessels supplying the graft, the detection of pancreatic fluid collections, including pseudocysts, abscesses, or leaks, the assessment of bowel complications (anastomotic leaks, ileus or obstruction), and the identification of bleeding. The aim of this pictorial review is to illustrate CT findings of surgical-related complications after pancreatic transplantation. The knowledge of surgical techniques is of key importance to understand postoperative anatomic changes and imaging evaluation. Therefore, we first provide a short summary of the main techniques of pancreatic transplantation. Then, we provide a practical imaging approach to pancreatic transplantation and its complications providing tips and tricks for the prompt imaging diagnosis on CT.

Bone mineral density progression following long-term simultaneous pancreas-kidney transplantation in type-1 diabetes

INTRODUCTION

Simultaneous pancreas-kidney transplantation (SPKT) has demonstrated favorable impact on the progression of chronic complications in type-1 diabetes (T1D) and terminal chronic kidney disease (CKD). However, some CKD mineral and bone disorders (CKD-MBD) may persist, even after transplantation. There are only a few studies addressing the long-term progression of bone mineral density (BMD) in these patients. Our aim was to assess baseline BMD and long-term progression and consequences in patients with T1D undergoing SPKT.

METHODS

A retrospective cohort included patients undergoing SPKT in our tertiary center between 2000 and 2017. BMD progression was assessed on dual X-ray absorptiometry (DXA). Only patients with baseline data and a minimum follow-up of 2 years were included.

RESULTS

Seventy-three patients were included, 53.4% male, with a median age at SPKT of 35 years (interquartile range [IQR] 31; 39). At transplantation, the median T-scores for the lumbar spine (LS) and femoral neck (FN) were -1.6 (IQR -2.6; -1.1) and --2.1 (IQR -2.7; -1.6), respectively. Seventy-five percent of patients presented low BMD (osteopenia or osteoporosis) in the LS and 90% in the FN, with 33% osteoporosis in the LS and 36% in the FN. On multivariate analysis, male gender (odds ratio [OR] 10.82, 95% confidence interval (CI) 2.88-40.70) and low body-mass index (BMI) (OR 0.73, 95% CI 0.55-0.97) were significantly associated with lumbar but not femoral osteoporosis. At long-term follow-up, BMD significantly improved in the LS (ΔT-score +0.41, P<0.001) and FN (ΔT-score +0.29, P=0.01), at a median 4 years after SPKT. Twelve (16.4%) and 9 (12.3%) patients showed persistent FN and LS osteoporosis, respectively. Multivariate linear regression showed that high BMI was predictive of improvement in BMD.

CONCLUSIONS

This study demonstrated severe skeletal fragility in T1D patients with terminal CKD undergoing SPKT, more than a quarter of whom showed osteoporosis. The significant improvement in BMD may result from metabolic correction by SPKT and from physiological skeleton mineralization, which continues in this age group. BMD progression was positively associated with BMI, due to improved nutritional balance after transplantation.

The influence of simultaneous pancreas-kidney transplantation on the evolution of diabetic foot lesions and peripheral arterial disease

PURPOSE

Simultaneous pancreas-kidney transplantation (SPKT) remains the best treatment option in patients with type 1 diabetes and chronic kidney failure. There are only a few studies addressing the potential ischemic deterioration of peripheral arterial disease (PAD) due to blood diverting from the iliac artery to the kidney graft. We aimed to evaluate diabetic foot lesions and PAD evolution in SPKT recipients and investigate if they are more frequent in ipsilateral lower limb of kidney graft.

METHODS

We developed a retrospective cohort, including patients submitted to SPKT in our tertiary center, between 2000 and 2017. Diabetic foot lesions and PAD frequencies were compared in the period before and after transplantation.

RESULTS

Two hundred and eleven patients were included, 50.2% (n = 106) female, with a median age at transplantation of 35 years (IQR 9). After a median follow-up period of 10 years (IQR 7), patient, kidney, and pancreatic graft survival were 90.5% (n = 191), 83.4% (n = 176), and 74.9% (n = 158), respectively. Before transplant, 2.8% (n = 6) had PAD and 5.3% (n = 11) had history of foot lesions. In post-transplant period, 17.1% (n = 36) patients presented PAD and 25.6% (n = 54) developed diabetic foot ulcers, 47.6% (n = 35) of which in the ipsilateral and 53.3% (n = 40) in the contralateral lower limb of the kidney graft (p = 0.48). Nine patients (4.3%) underwent major lower limb amputation, 3 (30%) ipsilateral and 7 (70%) contralateral to the kidney graft (p = 0.29).

CONCLUSIONS

Diabetic foot lesions were not more frequent in the ipsilateral lower limb of the kidney graft, therefore downgrading the 'steal syndrome' role in these patients.

Biofabrication of microcapsules encapsulating beta-TC-6 cells via scalable device and in-vivo evaluation in type 1 diabetic mice

Type 1 diabetes mellitus (T1DM) is a disease characterized by lack of pancreatic islet function. Whole tissue transplantation appears to be a viable alternative in the management of T1DM. This study aims at the fabrication and evaluation of alginate-chitosan microcapsules encapsulating insulin-secreting beta-TC-6 cells using an automated spraying nozzle. Uniform spherical microcapsules (250-350 µm) encapsulated with beta-TC-6 cells were fabricated in large quantities in a short span of time. Microencapsulated beta-TC-6 cells were transplanted intraperitoneally into streptozotocin (STZ) induced diabetic mice and monitored for immune tolerance and decrease in blood glucose levels. Mice that received microencapsulated beta-TC-6 cells maintained normoglycemia for 35 ± 5 days before rejection. However, the group that received naked beta-TC-6 cells rejected the cells within 1-2 days, unable to control elevated blood glucose levels. They also exhibited high immune reactions, as evidenced by elevated levels of CD8⁺ and CD62L T cells. CD4⁺ T cells that mediated a Th2 response (humoral response) were predominant in microencapsulated beta-TC-6 cells and cells only group as evidenced by elevated levels of CD45R. Our findings from the in-vivo study demonstrated that transplantation of microencapsulated beta-TC-6 cells can be a viable alternative in the management of T1DM with acceptable immune response.

Pancreas Transplantation at a Single Latin-American Center; Overall Results with Type 1 and Type 2 Diabetes Mellitus

BACKGROUND

Simultaneous pancreas-kidney transplantation (SPK) has become the treatment of choice for type 1 diabetes mellitus (T1DM) patients with chronic renal failure. Type 2 diabetes mellitus (T2DM), was once considered to be a contraindication for pancreas transplantation; however, it has been accepted as a new indication, under strict criteria. Although favorable results have increase the indication for T2DM in developed countries, there have been no reports of long-term results for this indication from Latin American centers.

METHODS

From April 2008 to March 2016, patients receiving SPK or pancreas transplant alone (PTA) for T2DM were included and compared with T1DM recipients. Variables were compared between groups with the use of χ² and t tests; Kaplan-Meier with log rank was used for patient and graft survivals; P < .05 was considered to be significant.

RESULTS

A total of 45 SPK and 1 PTA were performed, 35 (76.1%) for T1DM and 11 (24.5%) for T2DM. Mean pre-transplantation C-peptide was significantly higher in the T2DM group (P = .01); HbA_1c was higher in the T1DM group (P = .03). No differences were found in weight, body mass index, and pre-transplantation glycemia. Patient survivals for T1DM recipients were 88.2% and 84.8% at 1 and 5 years, respetively, versus 100% and 74.1% for T2DM recipients (P = .87).

CONCLUSIONS

Our initial prospective experience in a single Latin American center showed that medium- and long-term outcomes for T1DM and T2DM individuals receiving pancreas transplants are similar, under strict selection criteria.

Current outcomes in islet versus solid organ pancreas transplant for β-cell replacement in type 1 diabetes

PURPOSE OF REVIEW

With continued optimization of islet isolation and immunosuppression protocols, the medium-term rates of insulin independence following islet transplantation have improved significantly. This review evaluates the most up-to-date outcomes data for both solid organ pancreas and islet transplantation to develop an algorithm for selection of β-cell replacement in type 1 diabetes patients.

RECENT FINDINGS

Solid organ pancreas and islet transplantation have both displayed improved rates of 5-year insulin independence, largely attributable to improvements in immunosuppressive regimens. The medium-term rates of insulin independence following islet transplantation in highly selected type 1 nonuremic diabetic recipients is beginning to approach the success rates observed following solitary pancreas transplantation.

SUMMARY

Although pancreas transplantation has historically been favored for β-cell replacement, current outcomes following islet transplantation justify the use of this minimally invasive therapy in carefully selected patients. Pancreas transplant remains the procedure of choice for β-cell replacement in uremic patients. Islet transplantation should be considered in nonuremic patients with low BMI and low insulin requirements, patients lacking the cardiovascular reserve to undergo open abdominal surgery, or patients who elect to forego the risks of a major operation in exchange for an increased risk of islet graft failure.

Simultaneous pancreas-kidney transplantation. Experience of the Doce de Octubre Hospital

INTRODUCTION

Simultaneous pancreas-kidney transplantation (SPKT) constitutes the therapy of choice for diabetes type1 or type2 associated with end-stage renal disease, because is the only proven method to restore normo-glicemic control in the diabetic patient.

METHODS

Retrospective and descriptive study of a series of 175 patients who underwent SPKT from March 1995 to April 2016. We analyze donor and recipient characteristics, perioperative variables and immunosuppression, post-transplant morbi-mortality, patient and graft survival, and risk factors related with patient and graft survival.

RESULTS

Median age of the donors was 28years and mean age of recipients was 38.8±7.3years, being 103 males and 72 females. Enteric drainage of the exocrine pancreas was performed in 113 patients and bladder drainage in 62. Regarding post-transplant complications, the overall rate of infections was 70.3%; graft pancreatitis 26.3%; intraabdominal bleeding 17.7%; graft thrombosis 12.6%; and overall pancreas graft rejection 10.9%. The causes of mortality were mainly cardiovascular and infectious complications. Patient survival at 1, 3 and 5-year were 95.4%, 93% and 92.4%, respectively, and pancreas graft survival at 1, 3 and 5-year were 81.6%, 77.9% y 72.3%, respectively.

CONCLUSIONS

In our 20-year experience of simultaneous pancreas-kidney transplantation, the morbidity rate, and 5-year patient and pancreas graft survivals were similar to those previously reported from the international pancreas transplant registries.

Pancreas-After-Islet Transplantation in Nonuremic Type 1 Diabetes: A Strategy for Restoring Durable Insulin Independence

Islet transplantation offers a minimally invasive approach for β cell replacement in diabetic patients with hypoglycemic unawareness. Attempts at insulin independence may require multiple islet reinfusions from distinct donors, increasing the risk of allogeneic sensitization. Currently, solid organ pancreas transplant is the only remaining surgical option following failed islet transplantation in the United States; however, the immunologic impact of repeated exposure to donor antigens on subsequent pancreas transplantation is unclear. We describe a case series of seven patients undergoing solid organ pancreas transplant following islet graft failure with long-term follow-up of pancreatic graft survival and renal function. Despite highly variable panel reactive antibody levels prior to pancreas transplant (mean 27 ± 35%), all seven patients achieved stable and durable insulin independence with a mean follow-up of 6.7 years. Mean hemoglobin A1c values improved significantly from postislet, prepancreas levels (mean 8.1 ± 1.5%) to postpancreas levels (mean 5.3 ± 0.1%; p = 0.0022). Three patients experienced acute rejection episodes that were successfully managed with thymoglobulin and methylprednisolone, and none of these preuremic type 1 diabetic recipients developed stage 4 or 5 chronic kidney disease postoperatively. These results support pancreas-after-islet transplantation with aggressive immunosuppression and protocol biopsies as a viable strategy to restore insulin independence after islet graft failure.

Identfication of key miRNAs in pancreatitis using bioinformatics analysis of microarray data

Pancreatitis is a type of inflammation in the pancreas, which frequently occurs due to alcohol and gallstones. The present study aimed to identify pancreatitis-associated microRNAs (miRNAs) by analyzing the microarray of GSE24279. GSE24279 was downloaded from the Gene Expression Omnibus, composed of a collective of 27 pancreatitis and 22 normal control samples. The differentially expressed miRNAs (DE-miRNAs) in pancreatitis samples were screened using the Limma package in Bioconductor. Subsequently, target genes of the DE-miRNAs were predicted using the miRecords and miRWalk databases. Their potential functions were analyzed by functional and pathway enrichment analysis using the Database for Annotation, Visualization and Integrated Discovery online tool. Finally, pancreatitis-associated genes among the target genes identified were searched using the Comparative Toxicogenomics Database, and a regulatory network of pancreatitis-associated genes and their target miRNAs were constructed using Cytoscape software. A total 14 upregulated and 39 downregulated miRNAs were identified in pancreatitis samples compared with control samples and 290 target genes of DE-miRNAs were determined. Cyclin D1 (CCND1), v-akt murine thymoma viral oncogene homolog 2 (AKT2), cyclin-dependent kinase 6 (CDK6) and SMAD family member 2 (SMAD2) were involved in the pathway of pancreatic cancer. Among the target genes, 279 genes were pancreatitis-associated genes, which in turn were targeted by 37 miRNAs in the regulatory network. Hsa-miR-15a, hsa-miR-16, hsa-miR-155, hsa-miR-375 and hsa-miR-429 in particular may be involved in pancreatitis by targeting genes in the regulatory network, including hsa-miR-15a→CCND1, hsa-miR-16→CCND1, hsa-miR-155→CCND1/SMAD2, hsa-miR-375→AKT2/CDK6 and hsa-miR-429→CCND1. The above miRNAs and their targets may contribute to the pathogenesis of pancreatitis; therefore, they may be potential therapeutic targets.

A Comparative Analysis of the Safety, Efficacy, and Cost of Islet Versus Pancreas Transplantation in Nonuremic Patients With Type 1 Diabetes

Few current studies compare the outcomes of islet transplantation alone (ITA) and pancreas transplantation alone (PTA) for type 1 diabetes (T1D). We examined these two beta cell replacement therapies in nonuremic patients with T1D with respect to safety, graft function and cost. Sequential patients received PTA (n = 15) or ITA (n = 10) at our institution. Assessments of graft function included duration of insulin independence; glycemic control, as measured by hemoglobin A1c; and elimination of severe hypoglycemia. Cost analysis included all normalized costs associated with transplantation and inpatient management. ITA patients received one (n = 6) or two (n = 4) islet transplants. Mean duration of insulin independence in this group was 35 mo; 90% were independent at 1 year, and 70% were independent at 3 years. Mean duration of insulin independence in PTA was 55 mo; 93% were insulin independent at 1 year, and 64% were independent at 3 years. Glycemic control was comparable in all patients with functioning grafts, as were overall costs ($138 872 for ITA, $134 748 for PTA). We conclude that with advances in islet isolation and posttransplant management, ITA can produce outcomes similar to PTA and represents a clinically viable option to achieve long-term insulin independence in selected patients with T1D.

Role of dipeptidyl peptidase-4 inhibitors in new-onset diabetes after transplantation

Despite strict pre- and post-transplantation screening, the incidence of new-onset diabetes after transplantation (NODAT) remains as high as 60%. This complication affects the risk of cardiovascular events and patient and graft survival rates. Thus, reducing the impact of NODAT could improve overall transplant success. The pathogenesis of NODAT is multifactorial, and both modifiable and nonmodifiable risk factors have been implicated. Monitoring and controlling the blood glucose profile, implementing multidisciplinary care, performing lifestyle modifications, using a modified immunosuppressive regimen, administering anti-metabolite agents, and taking a conventional antidiabetic approach may diminish the incidence of NODAT. In addition to these preventive strategies, inhibition of dipeptidyl peptidase-4 (DPP4) by the gliptin family of drugs has recently gained considerable interest as therapy for type 2 diabetes mellitus and NODAT. This review focuses on the role of DPP4 inhibitors and discusses recent literature regarding management of NODAT.

Cooperative Study of the Spanish Pancreas Transplant Group (GETP): Surgical Complications

Technical failure in pancreas transplant has been the main cause of the loss of grafts. In the last few years, the number of complications has reduced, and therefore the proportion of this problem.

OBJECTIVES

The Spanish Pancreas Transplant Group wanted to analyze the current situation with regard to surgical complications and their severity.

MATERIAL AND METHODS

A retrospective and multicenter study was performed. 10 centers participated, with a total of 410 pancreas transplant recipients between January and December 2013.

RESULTS

A total of 316 transplants were simultaneous with kidney, 66 after kidney, pancreas-only 10, 7 multivisceral and 11 retrasplants. Surgical complication rates were 39% (n=161). A total of 7% vascular thrombosis, 13% bleeding, 6% the graft pancreatitis, 12% surgical infections and others to a lesser extent. Relaparotomy rate was 25%. The severity of complications were of type IIIb (13%), type II (12%) and type IVa (8.5%). Graft loss was 8%. Early mortality was 0.5%. The percentage of operations for late complications was 17%.

CONCLUSIONS

The number of surgical complications after transplantation is not negligible, affecting one in 3 patients. They are severe in one out of 5 and, in one of every 10 patients graft loss occurs. Therefore, there is still a significant percentage of surgical complications in this type of activity, as shown in our country.

Simultaneous pancreas-kidney transplantation: The role in the treatment of type 1 diabetes and end-stage renal disease

Type 1 diabetes mellitus (DM) is one of the most common and debilitating diseases to affect the world. Many patients are afflicted by microvascular and macrovascular complications, and succumb to end-stage renal disease (ESRD). Although dialysis and insulin therapy provides better glycemic control, it nonetheless significantly decreases a patient's quality of life. Moreover, they cannot reverse ESRD or alleviate complications. Simultaneous pancreas-kidney (SPK) transplantation has revolutionized the way we manage type 1 DM; it provides a physiological means of achieving normoglycemia while rendering patients free of dialysis. Understanding this procedure is important because it is becoming a more common management strategy for patients with type 1 DM. In this review, we will begin with a brief summary of type 1 DM, followed by a comprehensive description of SPK procedure, including the history and technique. We will then present the outcomes of transplantation.

Experience with 53 portal-duodenal drained solitary pancreas transplants

Systemic-enteric drainage is currently the most common technique for pancreas transplantation (PT). A novel alternative technique, portal-duodenal drainage (PDD), has potential physiological benefits and provides improved monitoring of the pancreatic graft. The current study describes 53 solitary PT procedures (43 pancreas after kidney and 10 pancreas transplant alone) using the PDD technique over the last three yr. This method resulted in one-yr patient survival at 96% and 83% graft survival. There were five cases (9.4%) of thrombosis, in which transplantectomy and two-layer closure of the native duodenum were performed. No fistulas were observed. Here, we demonstrate that the PDD technique in PT was as safe and effective as current techniques in clinical use.

Early pancreas allograft thrombosis

OBJECTIVES

To determine factors associated with early pancreatic allograft thrombosis (EPAT). Thrombosis is the leading non-immunological cause of early pancreatic allograft failure. Multiple risk factors have been postulated. We hypothesized that recipient perioperative hypotension was a major risk factor and evaluated the correlation of this and other parameters with EPAT.

METHODS

We retrospectively reviewed the records of the 118 patients who received a pancreatic allograft at our center between October 1992 and January 2010. Multiple donor and recipient parameters were analyzed as associates of EPAT by univariate and multivariate analysis.

RESULTS

There were 12 episodes of EPAT, resulting in an incidence of 10.2%. On univariate analysis, EPAT was associated with perioperative hypotension, vasopressor use, and neuropathy in the recipient (p ≤ 0.04 for all). On multivariate analysis corrected for age, sex, and peripheral vascular disease, only vasopressor use retained a significant association with EPAT with a hazard ratio of 8.74 (CI 1.11-68.9, p = 0.04). Factors associated with vasopressor use included recipient ischemic heart disease, peripheral vascular disease, retinopathy or neuropathy, and any surgical complication.

CONCLUSIONS

Significant hypotension, measured by the need for perioperative vasopressor use was associated with EPAT, suggesting that maintenance of higher perfusion pressures may avoid this complication.

Excellent outcomes of simultaneous pancreas kidney transplantation in patients from rural and urban Australia: a national service experience

BACKGROUND

Simultaneous pancreas and kidney (SPK) transplantation is performed to restore normoglycemia and renal function in patients with type 1 diabetes mellitus and end-stage renal failure. The National Pancreas Transplant Unit (NPTU) in Sydney provides a service to a population spread across 7.4 million km. We aimed to see if SPK transplantation outcomes differed between recipients from metropolitan (M) centers and those from nonmetropolitan (NM) regions.

METHODS

Using a prospectively collected database, patient and graft survival were analyzed. Patients were categorized according to region of residence and by distance from the NPTU.

RESULTS

Between January 2001 and May 2010, 165 patients underwent first-time SPK transplantation at the NPTU. There were 126 M and 39 NM recipients. Median distance from the NPTU was 732 km for donors (range, 0-3930 km) and 887 km for recipients (range, 1-4114 km). Median follow-up was 5.2 years (range, 1.1-10.3 years). Actuarial 5-year patient survival was 94% in M and 95% in NM groups. At 5 years, non-death-censored pancreas graft survival was 75% and 82% among M and NM patients, respectively, while kidney allograft survival was 88% in M and 92% in NM groups. There was no significant difference in patient and graft survival between groups. Distance of donor and recipient from the NPTU did not influence graft or patient survival.

CONCLUSIONS

SPK transplantation can be performed with excellent outcomes at a national center with a vast catchment area, irrespective of donor or recipient location.

Impact of simultaneous pancreas-kidney transplantation: patients' perspectives

BACKGROUND

Few qualitative studies of simultaneous pancreas-kidney transplantation (SPK Tx) have been published. The aims of this study were to explore from the perspective of patients, the experience of living with diabetes mellitus type 1 (T1DM), suffering from complications, and undergoing SPK Tx with good outcome; and to determine the impact of SPK Tx on patients and their social and cultural environment.

METHODS

We performed a focused ethnographic study. Twenty patients were interviewed. Data were analyzed using content analysis and constant comparison following the method proposed by Miles and Huberman.

RESULTS

A functioning SPK Tx allowed renal replacement therapy and insulin to be discontinued. To describe their new situation, patients used words and phrases such as "miracle", "being reborn" or "coming back to life". Although the complications of T1DM, its surgery and treatment, and associated psychological problems did not disappear after SPK Tx, these were minimized when compared with the pretransplantation situation.

CONCLUSION

For patients, SPK Tx represents a recovery of their health and autonomy despite remaining problems associated with the complications of T1DM and SPK Tx. The understanding of patients' existential framework and their experience of disease are key factors for planning new intervention and improvement strategies.

Outcomes of simultaneous pancreas-kidney transplantation in type 2 diabetic recipients

BACKGROUND AND OBJECTIVES

Type 2 diabetic patients with end-stage renal disease may receive a simultaneous pancreas-kidney (SPK) transplant. However, outcomes are not well described. Risks for death and graft failure were examined in SPK type 2 diabetic recipients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using the United Network for Organ Sharing database, outcomes of SPK transplants were compared between type 2 and type 1 diabetic recipients. All primary SPK adult recipients transplanted between 2000 and 2007 (n=6756) were stratified according to end-stage pancreas disease diagnosis (type 1: n=6141, type 2: n=582). Posttransplant complications and risks for death and kidney/pancreas graft failure were compared.

RESULTS

Of the 6756 SPK transplants, 8.6% were performed in recipients with a type 2 diabetes diagnosis. Rates of delayed kidney graft function and primary kidney nonfunction were higher in the type 2 diabetics. Five-year overall and death-censored kidney graft survival were inferior in type 2 diabetics. After adjustment for other risk factors, including recipient (age, race, body weight, dialysis time, and cardiovascular comorbidities), donor, and transplant immune characteristics, type 2 diabetes was not associated with increased risk for death or kidney or pancreas failure when compared with type 1 diabetic recipients.

CONCLUSIONS

After adjustment for other risk factors, SPK recipients with type 2 diabetes diagnosis were not at increased risk for death, kidney failure, or pancreas failure when compared with recipients with type 1 diabetes.

Evolution of β-Cell Replacement Therapy in Diabetes Mellitus: Pancreas Transplantation

Diabetes mellitus remains one of the leading causes of morbidity and mortality worldwide. According to the Centers for Disease Control and Prevention, approximately 23.6 million people in the United States are affected. Of these individuals, 5-10% have been diagnosed with type 1 diabetes mellitus (TIDM), an autoimmune disease. Although it often appears in childhood, T1DM may manifest at any age. The effects of T1DM can be devastating, as the disease often leads to significant secondary complications, morbidity, and decreased quality of life. Since the late 1960s, surgical treatment for diabetes mellitus has continued to evolve and has become a viable alternative to chronic insulin administration. In this review, the historical evolution, current status, graft efficacy, benefits, and complications of pancreas transplantation are explored.

Minireview: beta-cell replacement therapy for diabetes in the 21st century: manipulation of cell fate by directed differentiation

Pancreatic beta-cell failure underlies type 1 diabetes; it also contributes in an essential way to type 2 diabetes. beta-Cell replacement is an important component of any cure for diabetes. The current options of islet and pancreas transplantation are not satisfactory as definitive forms of therapy. Here, we review strategies for induced de novo pancreatic beta-cell formation, which depend on the targeted differentiation of cells into pancreatic beta-cells. With this objective in mind, one can manipulate the fate of three different types of cells: 1) from terminally differentiated cells, e.g. exocrine pancreatic cells, into beta-cells; 2) from multipotent adult stem cells, e.g. hepatic oval cells, into pancreatic islets; and 3) from pluripotent stem cells, e.g. embryonic stem cells and induced pluripotent stem cells, into beta-cells. We will examine the pros and cons of each strategy as well as the hurdles that must be overcome before these approaches to generate new beta-cells will be ready for clinical application.

Long-term metabolic control of autoimmune diabetes in spontaneously diabetic nonobese diabetic mice by nonvascularized microencapsulated adult porcine islets

BACKGROUND

The long-term metabolic function of microencapsulated xenogeneic adult porcine islets (API) was assessed in a murine model of type 1 diabetes mellitus.

METHODS

API were encapsulated in barium-gelled alginate and transplanted intraperitoneally in diabetic nonobese diabetic (NOD) mice given no immunosuppression or given costimulatory blockade (CoB; CTLA4-Ig+anti-CD154 mAb). Control mice received nonencapsulated API under the kidney capsule. Graft function was monitored by measurement of random blood glucose levels, serum glycosylated hemoglobin (HbA1c), serum porcine C peptide, in vivo glucose tolerance tests, and histologic analyses of host pancreas and graft biopsies. Host immune responses to the islet xenografts were characterized by phenotyping peritoneal cellular infiltrates and by measuring serum antiporcine antibody levels.

RESULTS

Without immunosuppression, nonencapsulated API functioned for less than 1 week, and microencapsulated API functioned for 35+/-14 days before rejection, associated with both a cellular and a humoral immune response. With continuous CoB, nonencapsulated API functioned for 27+/-4 days, whereas microencapsulated API functioned for >450 days with measurable levels of serum porcine C peptide, near normal in vivo glucose tolerance tests and HbA1c levels, and intact microcapsules containing viable, insulin-positive porcine islets.

CONCLUSIONS

Microencapsulated API restored normoglycemia for more than 1 year in spontaneously diabetic NODs given dual CoB. To our knowledge, this is the first study to document long-term normalized HbA1c, porcine C peptide, and near normal glucose tolerance in immunosuppressed diabetic NOD mice transplanted intraperitoneally with microencapsulated API. Our study suggests that transplantation of microencapsulated porcine islet xenografts may be a future treatment for patients with type 1 diabetes mellitus.

Transplante de pâncreas e ilhotas em portadores de diabetes melito

O transplante simultâneo de pâncreas/rim tem indicações específicas, riscos e benefícios. O procedimento, cada vez mais realizado, traz vantagens se comparado ao paciente em diálise, em relação à qualidade de vida, anos de vida ganhos e evolução das complicações crônicas. Se o paciente tiver a opção de realizar o transplante de rim com doador vivo, que apresenta sobrevida semelhante do enxerto e do paciente aos dez anos, o procedimento deverá ser considerado. O transplante de pâncreas após rim, quando efetivo, pode melhorar a evolução das complicações cardiovasculares, mas em contrapartida provoca maior mortalidade nos primeiros meses após a cirurgia. O transplante isolado de pâncreas também ocasiona a maior mortalidade pós-operatória, resultado da complexidade do procedimento e da imunossupressão. O transplante de ilhotas tem sua indicação para um seleto grupo de diabéticos com instabilidade glicêmica.

Toward cell-based therapy of type I diabetes

Type 1 diabetes (T1D) is an autoimmune disease that results from the destruction of insulin-producing pancreatic islet cells owing to the aggressive effector function of autoreactive T cells. In addition to lifetime supply of exogenous insulin, whole-pancreas or islet transplantation is presently the only alternative therapy for severely ill patients. Here, we discuss the current status of the development of cell-based therapies that are based on essentially two options, i.e. replacement of islet cells by islet-like cells derived from embryonic or adult stem cells, and re-establishment of immunological tolerance to islet self-antigens through regulatory T cells and/or tolerance-promoting monocyte-derived cells. A combination of both approaches will be required to turn cell-based therapy of T1D into clinical success.