Results of pancreas transplantation alone with special attention to native kidney function and proteinuria in type 1 diabetes patients

Impact of pancreas transplantation alone on kidney function: A multicenter clinical cohort study

Pancreas transplantation alone (PTA) is a β cell replacement option for selected patients with type 1 diabetes mellitus; concerns have been raised regarding deterioration in kidney function (KF) after PTA. This retrospective multicenter study assessed actual impact of transplantation and immunosuppression on KF in PTA recipients at three Transplant Centers. The primary composite endpoint 10 years after PTA was >50% eGFR decline, eGFR < 30 mL/min/1.73 m2 , and/or receiving a kidney transplant (KT). Overall, 822 PTA recipients met eligibility. Median baseline and 10-year eGFR (mL/min/1.73 m2 ) were 76.3 (58.1-100.8) and 51.3 (35.3-65.9), respectively. Primary composite endpoint occurred in 98 patients (53.5%) with 45 experiencing a >50% decrease in eGFR by 10 years post-transplant, 38 eGFR < 30 mL/min/1.73 m2 and 49 requiring KT. KF declined most significantly within 6 months post-PTA, more often in females and patients with better preserved GFR up to 5 years with 11.6% kidney failure at 10 years. Patient survival and death-censored graft survival were both 68% at 10 years with overall graft thrombosis rate 8%. KF declined initially after PTA but stabilized with further slow progression. In conclusion, prospective intervention studies are needed to test renal sparing interventions while gathering more granular data.

First World Consensus Conference on pancreas transplantation: Part II - recommendations

The First World Consensus Conference on Pancreas Transplantation provided 49 jury deliberations regarding the impact of pancreas transplantation on the treatment of diabetic patients, and 110 experts' recommendations for the practice of pancreas transplantation. The main message from this consensus conference is that both simultaneous pancreas-kidney transplantation (SPK) and pancreas transplantation alone can improve long-term patient survival, and all types of pancreas transplantation dramatically improve the quality of life of recipients. Pancreas transplantation may also improve the course of chronic complications of diabetes, depending on their severity. Therefore, the advantages of pancreas transplantation appear to clearly surpass potential disadvantages. Pancreas after kidney transplantation increases the risk of mortality only in the early period after transplantation, but is associated with improved life expectancy thereafter. Additionally, preemptive SPK, when compared to SPK performed in patients undergoing dialysis, appears to be associated with improved outcomes. Time on dialysis has negative prognostic implications in SPK recipients. Increased long-term survival, improvement in the course of diabetic complications, and amelioration of quality of life justify preferential allocation of kidney grafts to SPK recipients. Audience discussions and live voting are available online at the following URL address: http://mediaeventi.unipi.it/category/1st-world-consensus-conference-of-pancreas-transplantation/246.

Simultaneously Transplanted Pancreas Improves Salivation and Reduces Oral Fungal Infections Incidence in Type 1 Diabetic Renal Transplant Recipients

BACKGROUND

Long-lasting diabetes mellitus may lead to numerous pathologies in the oral cavity. The aim of the study was to assess the condition of the oral cavity, caries intensity, salivary parameters, and incidence of oral fungal infections in patients with type 1 diabetes (T1D) and end-stage renal disease (ESRD) after kidney transplantation (KTx) or simultaneous kidney and pancreas transplantation (SPK).

METHODS

Twenty-one patients after SPK, 18 T1D patients after KTx, and 14 kidney recipients without diabetes (control group) were included in the study. Donor sources complied with Helsinki Congress and the Declaration of Istanbul.

RESULTS

Approximal plague index in SPK (80% [68%-90%]) was comparable to KTx (80% [37.5%-92.5%]) but higher than in control group (46% [35%-50%]). All 3 groups did not differ in terms of decayed-missing-filled tooth index: 22.3 ± 4.8 vs 22.5 ± 4.5 vs 19.1 ± 4.9, respectively. Normal saliva resting secretion and consistency were more common in SPK (71.4% and 52%, respectively) than in KTx (27.8% and 50.0%, respectively). Stimulated saliva volume in the SPK, KTx and controls, pH value, and buffering capacity were comparable. In KTx higher incidence of Candida albicans infection (55.6%) compared with SPK (23.8%) and controls (no infection) was observed.

CONCLUSIONS

Simultaneously transplanted pancreas improves salivation and reduces the incidence of oral fungal infections in T1D kidney recipients. The severity of caries is higher and oral hygiene is worse in T1D kidney recipients compared with patients after KTx without diabetes.

Endothelial function after pancreas transplantation-A single-center observational study

BACKGROUND

Patients with diabetes mellitus treated with successful pancreas transplantation (PTX) normalize hyperglycemia, but are exposed to immunosuppressive drugs that may impair endothelial function. This study aimed to evaluate endothelial function in single PTX recipients.

METHODS

Flow-mediated dilatation (FMD) in the brachial artery was measured by ultrasound 8 weeks after transplantation in single PTX (n = 27) and compared with healthy controls (n = 58), simultaneous pancreas and kidney recipients (n = 9), and kidney transplant recipients with (n = 41) and without (n = 95) diabetes mellitus. Adjustments for age, gender, blood pressure, and body mass index were included in a linear regression model. Changes in FMD from before to 1 year after transplantation were assessed in a subgroup of PTX recipients (n = 9).

RESULTS

Flow-mediated dilatation% in PTX recipients was not inferior to healthy controls (8.7 ± 3.6 vs 7.7 ± 3.3, P = .06) and simultaneous pancreas and kidney recipients (6.7 ± 4.5, P = .24) in an adjusted model, and superior to kidney recipients with and without diabetes (3.0 ± 3.0 and 4.8 ± 3.3, respectively, both P < .005). FMD% improved significantly from eight weeks to one year after PTX, mean 7.9 ± 4.2% vs 11.8 ± 4.8% (N = 9; P = .03).

CONCLUSION

Flow-mediated dilatation is well preserved in patients undergoing pancreas transplantation and is not impaired when immunosuppressive drugs are introduced.

Progression of diabetic nephropathy after successful pancreas transplantation alone: a case report

Pancreas transplantation is the only method that can nearly cure insulin-dependent diabetes mellitus. However, the effect of pancreas transplantation on patients with diabetic nephropathy has recently been considered controversial. In this report, we present a case of abrupt aggravation of proteinuria after successful pancreas transplantation alone without evidence of calcineurin inhibitor (CNI) toxicity. A 22-year-old female patient with type I diabetes mellitus underwent pancreas transplantation alone. The patient already had retinopathy and mild proteinuria, which in this case, may mean diabetic nephropathy. Her glucose levels were managed within the normal range after successful pancreas transplantation. However, the amount of proteinuria fluctuated. Kidney needle biopsy was performed owing to severe elevation of proteinuria, 2 years after the transplantation. Electron microscopy revealed diabetic glomerulosclerosis without evidence of CNI toxicity. This case indicates that diabetic nephropathy can be aggravated after pancreas transplantation, despite well-managed glucose levels and absence of CNI toxicity.

Pancreatic transplantation: Brief review of the current evidence

Kidney transplantation is the treatment of choice for management of end-stage renal disease. However, in diabetic patients, the underlying metabolic disturbance will persist and even may get worse after isolated kidney transplantation. Pancreatic transplantation in humans was first introduced in 1966. The initial outcome was disappointing. However, this was changed after the improvement of surgical techniques together with better patient selection and the availability of potent and better-tolerated immune-suppression like cyclosporine and induction antibodies. Combined kidney and pancreas transplantation will not only solve the problem of organ failure, but it will also stabilise or even reverse the metabolic complications of diabetes. Combined kidney and pancreas transplantation have the best long term outcome in diabetic cases with renal failure. Nevertheless, at the cost of an initial increase in morbidity and risk of mortality. Other transplantation options include pancreas after kidney transplantation and islet cell transplantation. We aim by this work to explore various options which can be offered to a diabetic patient with advanced chronic kidney disease. Our work will provide a simplified, yet up-to-date information regarding the different management options for those diabetic chronic kidney failure patients.

Two-stage Enteric Exclusion to Salvage a Pancreas Transplant After an Early Post-transplant Leak

Early technical complications after pancreas transplantation are almost always unsalvageable. The two most common complications are vascular thrombosis and duodenal anastomotic leaks. We present a case of a duodenal stump leak that led to a large abscess and severe sepsis. The pancreas was salvaged by repairing the leak and creating a proximal diverting ileostomy. Several months later, the ileostomy was reversed. This was done by creating a defunctionalized Roux limb to exclude the pancreas. The patient healed well and continued to enjoy excellent glucose control.

Islet Transplantation Alone Versus Solitary Pancreas Transplantation: an Outcome-Driven Choice?

PURPOSE OF REVIEW

In patients with type 1 diabetes with extreme glycemic variability, the restoration of pancreas endocrine function is potentially and completely achieved with islets of Langerhans (tissue derived from whole organ) or pancreas (whole organ) transplantation. The aim of our review is to report on the latest studies and to highlight the benefits and risks of the two procedures, providing clearer, more selective, evidence-based clinical indications that also consider the impact on the degenerative complications of diabetes as a potential benefit.

RECENT FINDINGS

Clinical experience in this field has been dynamic over the last three decades, and has been characterized by the development of more standardized protocols and a clearer definition of clinical outcome. On the contrary, the recommendations thus far are not well delineated and tend to overlap, and the past ADA position statement for pancreas transplant alone has also been applied to islet transplant alone, without differentiation. Both outcome-driven and non-outcome-driven criteria are considered in the conclusions, in an attempt to streamline indications for islet-alone or pancreas-alone transplantation.

Preserved insulin secretion and kidney function in recipients with functional pancreas grafts 1 year after transplantation: a single-center prospective observational study

OBJECTIVE

Successful simultaneous pancreas and kidney transplantation (SPK) or pancreas transplantation alone (PTA) restores glycemic control. Diabetes and impaired kidney function are common side effects of immunosuppressive therapy. This study addresses glucometabolic parameters and kidney function during the first year.

METHODS

We examined 67 patients with functioning grafts (SPK n = 30, PTA n = 37) transplanted between September 2011 and November 2016 who underwent repeated oral glucose tolerance tests (OGTTs) 8 and 52 weeks after transplantation. Another 19 patients lost their graft the first year post-transplant and 28 patients did not undergo repeated OGTTs and could not be studied. All patients received ATG induction therapy plus tacrolimus, mycophenolate and prednisolone. Glomerular filtration rate was measured before and 8 and 52 weeks after transplantation by serum clearance methods.

RESULTS

From week 8 to 52 after transplantation, mean fasting glucose decreased (SPK: 5.4 ± 0.7 to 5.1 ± 0.8 mmol/L, PTA: 5.4 ± 0.6 to 5.2 ± 0.7 mmol/L; both P < 0.05), and also 120-min post-OGTT glucose (SPK: 6.9 ± 2.9 to 5.7 ± 2.2 mmol/L; P = 0.07, PTA: 6.5 ± 1.7 to 5.7 ± 1.2 mmol/L; P < 0.05). Fasting C-peptide levels also decreased (SPK: 1500 ± 573 to 1078 ± 357 pmol/L, PTA: 1210 ± 487 to 1021 ± 434 pmol/L, both P < 0.005). Measured GFR decreased from enlistment to 8 weeks post transplant in PTA patients (94 ± 22 to 78 ± 19 mL/min/1.73 m2; P < 0.005), but did not deteriorate from week 8 to week 52 (SPK: 55.0 ± 15.1 vs 59.7 ± 11.3 ml/min/1.73 m²; P = 0.19, PTA: 76 ± 19 vs 77 ± 19 mL/min/1.73 m²; P = 0.74).

CONCLUSION

Glycemic control and kidney function remain preserved in recipients with functioning SPK and PTA grafts 1 year after transplantation.

Long-term diabetes complications after pancreas transplantation

PURPOSE OF REVIEW

The intention of this study is to summarize present knowledge about adverse effects of hyperglycemia in diabetes, and in this context review more recent data concerning the effects of pancreas transplantation on a wide range of diabetic complications.

RECENT FINDINGS

Effective blood glucose control by insulin delays progression of microvascular complications and probably improves survival in type 1 diabetes. A successful pancreas transplantation combined with a kidney graft has recently been found to prevent diabetic kidney lesions, and registry data support improved long-term patient survival. Cardiovascular mortality was reduced in one study, even though coronary heart disease was not significantly altered. Advanced coronary lesions may be too advanced in these patients at baseline. However, with a successful single pancreas transplant, which is generally performed in patients with near-normal kidney function, pancreas transplantation may improve left ventricular function. Development of retinopathy and neuropathy is delayed with functioning pancreas grafts, and both quality of life and certain skin lesions may improve after pancreas transplantation.

SUMMARY

In patients with type 1 diabetes, pancreas transplantation may improve cardiac outcomes and ameliorate diabetic lesions in the kidney transplant. Also quality of life, neuropathy, retinopathy, and healing of certain skin lesions may be improved.

Benefits of Islet Transplantation as an Alternative to Pancreas Transplantation: Retrospective Study of More Than 10 Ten Years of Experience in a Single Center

BACKGROUND

Pancreas transplantation (PTx) represents the method of choice in type 1 diabetic patients with conservatively intractable hypoglycemia unawareness syndrome. In 2005, the Institute for Clinical and Experimental Medicine (IKEM) launched a program to investigate the safety potential of islet transplantation (ITx) in comparison to PTx.

AIM

This study aims to compare the results of PTx and ITx regarding severe hypoglycemia elimination, metabolic control, and complication rate.

METHODS

We analyzed the results of 30 patients undergoing ITx and 49 patients treated with PTx. All patients were C-peptide-negative and suffered from hypoglycemia unawareness syndrome. Patients in the ITx group received a mean number of 12,349 (6,387-15,331) IEQ/kg/person administered percutaneously into the portal vein under local anesthesia and radiological control. The islet number was reached by 1-3 applications, as needed. In both groups, we evaluated glycated hemoglobin, insulin dose, fasting and stimulated C-peptide, frequency of severe hypoglycemia, and complications. We used the Mann Whitney test, Wilcoxon signed-rank test, and paired t-test for analysis. We also individually assessed the ITx outcomes for each patient according to recently suggested criteria established at the EPITA meeting in Igls.

RESULTS

Most of the recipients showed a significant improvement in metabolic control one and two years after ITx, with a significant decrease in HbA1c, significant elevation of fasting and stimulated C-peptide, and a markedly significant reduction in insulin dose and the frequency of severe hypoglycemia. Seventeen percent of ITx recipients were temporarily insulin-independent. The results in the PTx group were comparable to those in the ITx group, with 73% graft survival and insulin independence in year 1, 68% 2 years and 55% 5 years after transplantation. There was a higher rate of complications related to the procedure in the PTx group. Severe hypoglycemia was eliminated in the majority of both ITx and PTx recipients.

CONCLUSION

This report proves the successful initiation of pancreatic islet transplantation in a center with a well-established PTx program. ITx has been shown to be the method of choice for hypoglycemia unawareness syndrome, and may be considered for application in clinical practice if conservative options are exhausted.

C-peptide as a Therapy for Kidney Disease: A Systematic Review and Meta-Analysis

C-peptide has intrinsic biological activity and may be renoprotective. We conducted a systematic review to determine whether C-peptide had a beneficial effect on renal outcomes. MEDLINE, EMBASE, and the Cochrane Central Databases were searched for human and animal studies in which C-peptide was administered and renal endpoints were subsequently measured. We identified 4 human trials involving 74 patients as well as 18 animal studies involving 35 separate experiments with a total of 641 animals. In humans, the renal effects of exogenously delivered C-peptide were only studied in type 1 diabetics with either normal renal function or incipient nephropathy. Pooled analysis showed no difference in GFR (mean difference, -1.36 mL/min/1.73 m2, p = 0.72) in patients receiving C-peptide compared to a control group, but two studies reported a reduction in glomerular hyperfiltration (p<0.05). Reduction in albuminuria was also reported in the C-peptide group (p<0.05). In diabetic rodent models, C-peptide led to a reduction in GFR (mean difference, -0.62 mL/min, p<0.00001) reflecting a partial reduction in glomerular hyperfiltration. C-peptide also reduced proteinuria (mean difference, -186.25 mg/day, p = 0.05), glomerular volume (p<0.00001), and mesangial matrix area (p<0.00001) in diabetic animals without affecting blood pressure or plasma glucose. Most studies were relatively short-term in duration, ranging from 1 hour to 3 months. Human studies of sufficient sample size and duration are needed to determine if the beneficial effects of C-peptide seen in animal models translate into improved long-term clinical outcomes for patients with chronic kidney disease. (PROSPERO CRD42014007472)

The therapeutic potential of C-peptide in kidney disease: a protocol for a systematic review and meta-analysis

BACKGROUND

Kidney disease remains a major cause of morbidity and mortality in Canada and worldwide. New medical treatments are needed to reduce the progression of kidney disease to improve patient outcomes. C-peptide is normally released by pancreatic beta-cells along with insulin in healthy individuals, and has been shown to have intrinsic biological activity and to potentially be renoprotective. The effect of exogenous C-peptide on kidney structure and function, and the role of C-peptide in the treatment of kidney disease have not yet been fully elucidated.

METHODS/DESIGN

We will conduct a systematic review of the literature in human clinical trials and mammalian experimental models to ascertain the current evidence for the role of C-peptide as a potential therapeutic agent for the treatment of kidney disease. We aim to identify whether exogenously delivered C-peptide has an effect on clinically relevant outcomes such as glomerular filtration rate, proteinuria, kidney histology, requirement of renal replacement therapy, and mortality. We will search MEDLINE, EMBASE, and the Cochrane Central Databases for human or animal studies in which C-peptide was administered and renal endpoints were subsequently measured. Study quality will be assessed using the Cochrane Collaboration's tool for assessing risk of bias. If appropriate, a meta-analysis will be performed as per standard techniques.

DISCUSSION

The results of this study will determine the potential role of C-peptide as a therapeutic intervention for patients with kidney disease and will help guide subsequent clinical trials. The study may also provide insight into which patients or disease states are likely to benefit the most from C-peptide.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42014007472.

Pancreas transplantation: a treatment option for people with diabetes

Since the first pancreas transplants in the early 1960s, whole-organ pancreas transplantation, either alone or combined with kidney transplantation, has become commonplace in many countries around the world. Whole-organ pancreas transplantation is available in the UK, with ~200 transplants currently carried out per year. Patient survival and pancreas graft outcome rates are now similar to other solid organ transplant programmes, with high rates of long-term insulin independence. In the present review, we will discuss whole-pancreas transplantation as a treatment for diabetes, focusing on indications for transplantation, the nature of the procedure performed, graft survival rates and the consequences of pancreas transplantation on metabolic variables and the progression of diabetes-related complications.

Pancreas transplant alone: a procedure coming of age

The goal of this review is to highlight the significant improvements, over the past four decades, in outcomes after a pancreas transplant alone (PTA) in patients with brittle diabetes and recurrent episodes of hypoglycemia and/or hypoglycemic unawareness. A successful PTA-in contrast to intensive insulin regimens and insulin pumps-restores normoglycemia without the risk of hypoglycemia and prevents, halts, or reverses the development or progression of secondary diabetes complications. In this International Pancreas Transplant Registry (IPTR) analysis, we reviewed the records of 1,929 PTA recipients from December 1966 to December 2011. We computed graft survival rates according to the Kaplan-Meier method and used uni- and multivariate analyses. In the most recent era (January 2007-December 2011), patient survival rates were >95% at 1 year posttransplant and >90% at 5 years. Graft survival rates with tacrolimus-based maintenance therapy were 86% at 1 year and 69% at 3 years and with sirolimus, 94 and 84%. Graft survival rates have significantly improved owing to marked decreases in technical and immunologic graft failure rates (P < 0.05). As a result, the need for a subsequent kidney transplant has significantly decreased, over time, to only 6% at 5 years. With patient survival rates of almost 100% and graft survival rates of up to 94% at 1 year, a PTA is now a highly successful long-term option. It should be considered in nonuremic patients with brittle diabetes in order to achieve normoglycemia, to avoid hypoglycemia, and to prevent the development or progression of secondary diabetes complications.

Follow-up of secondary diabetic complications after pancreas transplantation

PURPOSE OF REVIEW

Successful pancreas transplantation restores physiologic glycemic and metabolic control. Its effects on overall patient survival (especially for simultaneous pancreas-kidney transplantation) are clear-cut. We herein review the available literature to define the impact of pancreas transplantation on chronic complications of diabetes mellitus.

RECENT FINDINGS

With longer-term follow-up, wider patient populations, and more accurate investigational tools (clinical and functional tests, noninvasive imaging, histology, and molecular biology), growing data show that successful pancreas transplantation may slow the progression, stabilize, and even favor the regression of secondary complications of diabetes, both microvascular and macrovascular, in a relevant proportion of recipients.

SUMMARY

Patients who are referred for pancreas transplantation usually suffer from advanced chronic complications of diabetes, which have classically been deemed irreversible. A successful pancreas transplantation is often able to slow the progression, stabilize, and even reverse many microvascular and macrovascular complications of diabetes. Growing clinical evidence shows that the expected natural history of long-term diabetic complications can be significantly modified by successful pancreas transplantation.

Evolution of pancreas transplantation: long-term results and perspectives from a high-volume center

OBJECTIVE

To describe the evolution of pancreas transplantation from 1979 to 2011. The aim was to examine factors influencing long-term patient and graft survival, surgical methods, and risk factors influencing organ performance after transplantation.

BACKGROUND

Pancreas transplantation has become the therapy of choice for patients suffering insulin-dependent diabetes and end stage renal failure.

METHODS

Retrospective analysis of 509 consecutive pancreas transplants (442 simultaneous pancreas and kidney [SPK], 20 pancreas transplanted alone [PTA], and 47 pancreas transplanted after kidney [PAK]), performed at the University Hospital Innsbruck. The data were statistically analyzed using the Kaplan-Meier method and log-rank test.

RESULTS

After overcoming initial immunological and technical problems between 1979 and 1988 (5-year pancreas graft survival rate, 29.7%), pancreas transplantation evolved during the second decade (1989-1996; 5-year pancreas graft survival rate, 42.2%). Technical changes, optimized immunosuppression, careful pretransplant evaluation, and improved graft monitoring have become standard in the last decade and result in excellent 5-year patient (94.3%), kidney (89.4%), and pancreas (81.5%) graft survival. Five-year graft survival was superior in SPK (68.8%) compared with PAK (62.5%) and PTA (16.4%). SPK retransplantation can be carried out safely with 5-year patient (87.5%) and pancreas graft (75.0%) survival. Overall 5-year patient survival after loss of the first pancreas graft is significantly better in patients who underwent retransplantation (89.4% vs. 67.9%, P = 0.001). Long-term pancreas graft survival is independent of donor body mass index, sex, and cause of death, anastomosis time and the number of human leukocyte antigen (HLA) mismatches, recipient age, body mass index, sex, current panel reactive antibodies, and waiting time. Significant risk factors for reduced graft survival are cold ischemia time and donor age.

CONCLUSIONS

During the last 32 years, many problems in pancreas transplantation have been overcome and it may currently represent the therapeutic gold standard for some patients with diabetes and end stage renal failure.

Transplantation of the pancreas

Pancreas transplantation consistently induces insulin-independence in beta-cell-penic diabetic patients, but at the cost of major surgery and life-long immunosuppression. One year after grafting, patient survival rate now exceeds 95 % across recipient categories, while insulin independence is maintained in some 85 % of simultaneous pancreas and kidney recipients and in nearly 80 % of solitary pancreas transplant recipients. The half-life of the pancreas graft currently averages 16.7 years, being the longest among extrarenal grafts, and substantially matching the one of renal grafts from deceased donors. The difference between expected (100 %) and actual insulin-independence rate is mostly explained by technical failure in the postoperative phase, and rejection in the long-term period. Death with a functioning graft remains a further major issue, especially in uremic patients who have undergone prolonged periods of dialysis. Refinements in graft preservation, surgical techniques, immunosuppression, and prophylactic treatments are expected to further improve the results of pancreas transplantation.

In vitro generation of functional insulin-producing cells from human bone marrow-derived stem cells, but long-term culture running risk of malignant transformation

Efforts involving therapeutic islet cell transplantation have been hampered by limited islet availability and immune rejection. In vitro transdifferentiation of human bone marrow-derived stem (hBMDS) cells into functional insulin-producing cells promises to provide a tissue source for autologous cell transplantation. In this study, we isolated hBMDS cells, developed a single-cell-derived stem cell line, and induced the cells to differentiate into islet-like clusters. These islet-like cells expressed multiple genes related to islet development and beta cell function (e.g., Pdx-1, Ngn-3, Islet-1, Neuro-D, Pax4, IAPP, and insulin) and produced insulin and C-peptide within these cells. These islet-like cells demonstrated time-dependent glucose-stimulated insulin release, and the ability to ameliorate hyperglycemia in chemically induced diabetic mice. However, these transplanted differentiated cells became tumorigenic in diabetic immunocompromised mice and their spontaneous transformation was confirmed by a marked increase in growth rate and inactivation of tumor suppressor genes (P21 and P16) by promoter hypermethylation. In conclusion, while hBMDS cells can be transdifferentiated into competent insulin-producing cells, and while such cell might be a potential source for autologous cell therapy for type 1 diabetes, caution is strongly advised in view of the neoplastic propensity of hBMDS cells, especially after a long-term culture in vitro.