Equivalent success of simultaneous pancreas kidney and solitary pancreas transplantation. A prospective trial of tacrolimus immunosuppression with percutaneous biopsy

Graft dysfunction in simultaneous pancreas kidney transplantation (SPK): Results of concurrent kidney and pancreas allograft biopsies

Simultaneous pancreas and kidney transplants offer significant therapeutic advantages but present a diagnostic approach dilemma in the diagnosis of rejection. Because both organs are from the same donor, the kidney has been treated traditionally as the "sentinel" organ to biopsy, presumably representing the status of both allografts. Truly concurrent biopsy studies, however, are needed to confirm this hypothesis. We examined 101 concurrent biopsies from 70 patients with dysfunction in either or both organs. Results showed concurrent rejection in 23 of 57 (40%) of cases with rejection; 19 of 57 (33.5%) and 15 of 57 (26.5%) showed kidney or pancreas only rejection, respectively. The degree and type of rejection differed in the majority (13 of 23, 56.5%) of cases with concurrent rejection, with the pancreas more often showing higher rejection grade. Taking into account pancreas dysfunction, a positive kidney biopsy should correctly predict pancreas rejection in 86% of the instances. However, the lack of complete concordance between the 2 organs, the discrepancies in grade and type of rejection, and the tendency for higher rejection grades in concurrent or pancreas only rejections, all support the rationale for pancreas biopsies. The latter provide additional data on the overall status of the organ, as well as information on nonrejection-related pathologies.

Similar results with solitary pancreas transplantation compared with simultaneous pancreas-kidney transplantation in the new millennium

INTRODUCTION

The purpose of this study was to analyze our single-center outcomes according to pancreas transplant (PT) category in the new millennium by using standardized management protocols.

PATIENTS AND METHODS

We retrospectively studied 202 consecutive PTs (179 with portal-enteric drainage) in 192 patients; all received either rabbit antithymocyte globulin or alemtuzumab induction in combination with tacrolimus, mycophenolate mofetil, and tapered corticosteroids or early steroid withdrawal. Unlike simultaneous pancreas/kidney (SPK) transplant, solitary PT (SPT) recipients were managed with routine perioperative anticoagulation and surveillance pancreas biopsies.

RESULTS

From November 2001 to March 2013, we performed 162 SPK transplants, 35 pancreas after kidney transplants, and 5 pancreas-alone transplants (40 SPTs). Demographic characteristics were mostly comparable; however, the SPT group had younger donors, shorter waiting time, fewer HLA mismatches, and fewer African-American recipients but more retransplants (all, P < .05). With a mean follow-up of 5.5 versus 7.5 years, overall patient (86.4% SPK vs 86.8% SPT), kidney graft (74% SPK vs 80% SPT), and pancreas graft (both 65%) survival rates were comparable. Although mortality rates were similar, mortality patterns differed because no SPT recipients died early, whereas the 1-, 3-, and 5-year mortality rates after SPK transplant were 4%, 9% and 12%, respectively (P < .05). The most common causes of pancreas graft loss were death with functioning grafts in SPK recipients and acute/chronic rejection in SPT recipients. Rates of early thrombosis were 8.6% in SPK patients and 5% in SPT patients. Cumulative clinical acute rejection rates were similar between groups (SPK 29% vs SPT 27.5%; P = NS).

CONCLUSIONS

In the setting of depleting antibody induction and tacrolimus-based therapy, HLA matching, careful donor and recipient selection, portal-enteric drainage, selective perioperative anticoagulation, and surveillance SPT biopsy monitoring, similar medium-term outcomes can be achieved in SPK transplants and SPTs in the new millennium.

Diagnosis of early pancreas graft failure via antibody-mediated rejection: single-center experience with 256 pancreas transplantations

Early pancreas graft loss is usually attributed to technical failure while the possibility of antibody-mediated rejection (AMR) is generally overlooked. To investigate the role of AMR in early pancreas graft loss, we retrospectively assessed 256 patients with simultaneous pancreas-kidney transplantation (SPK) between 1985 and 2010 at our institute. We included 33 SPK patients who lost their pancreas graft <1 year after transplantation. AMR was diagnosed based on donor-specific antibodies, C4d and histology in 7 cases, 8 cases were suspicious for AMR and 18 pancreas graft losses were not due to AMR. Acute AMR occurred >1 month after transplantation in 6/7 cases, whereas all other causes typically led to loss <1 month after transplantation. Thrombotic lesions occurred equally among the 33 cases. In 12/18 concurrent kidney specimens, the diagnostic results paralleled those of the pancreas graft. All patients with acute AMR of the pancreas graft lost their renal grafts <1 year after transplantation. In the setting of a thrombotic event, histopathological analysis of early pancreas graft loss is advisable to rule out the possibility of AMR, particularly because a diagnosis of acute AMR has important consequences for renal graft outcomes.

Pancreas transplantation, antibodies and rejection: where do we stand?

PURPOSE OF REVIEW

Antibody-mediated rejection (AMR) is acknowledged and defined in kidney transplantation, but where do we stand as far as pancreas transplantation is concerned? Here we appraise the most recent findings in pancreatic AMR and give suggestions for future research in the field by addressing currently unresolved issues.

RECENT FINDINGS

Five main topics are discussed: chronological assessment of all literature on biopsy-proven pancreatic AMR; role of C4d and recent development in other markers; the use of sentinel organs, such as kidney biopsies and duodenal patch biopsies for diagnosis of pancreatic AMR; studies addressing islet pathology and its relevance in AMR; and protocol and follow-up pancreas biopsy practice in relation to pancreas transplant management and survival.

SUMMARY

Antibody-mediated processes play a role in pancreas transplantation. However, sensitive markers, pathophysiological understanding, and adequate interventions have not yet been established. Much data are still lacking and we believe that studying protocol and follow-up biopsies along with serial donor-specific antibody data may improve pancreas transplant patient management and outcomes.

Risks and benefits of transplantation in the cure of type 1 diabetes: whole pancreas versus islet transplantation. A single center study

BACKGROUND

Pancreas and islet transplantation are the only available options to replace beta-cell function in patients with type 1 diabetes. Great variability in terms of rate of success for both approaches is reported in the literature and it is difficult to compare the respective risks and benefits.

OBJECTIVES

The aim of this study was to analyze risks and benefits of pancreas transplantation alone (PTA) and islet transplantation alone (ITA) by making use of the long-term experience of a single center where both transplantations are performed. We focused on the risks and benefits of both procedures, with the objective of better defining indications and providing evidence to support the decision-making process. The outcomes of 33 PTA and 33 ITA were analyzed, and pancreas and islet function (i.e., insulin independence), perioperative events, and long-term adverse events were recorded.

RESULTS

We observed a higher rate of insulin independence in PTA (75%) versus ITA (59%), with the longer insulin independence among PTA patients receiving tacrolimus. The occurrence of adverse events was higher for PTA patients in terms of hospitalization length and frequency, re-intervention for surgical and immunological acute complications, CMV reactivation, and other infections.

CONCLUSIONS

In conclusion, these results support the practice of listing patients for PTA when the metabolic control and the progression of chronic complications require a rapid normalization of glucose levels, with the exception of patients with cardiovascular disease, because of the high surgical risks. ITA is indicated when replacement of beta-cell mass is needed in patients with a high surgical risk.

Eosinophilia as an early indicator of pancreatic allograft rejection

Monitoring pancreas transplant recipients for rejection is an inexact science. Serial monitoring of urinary amylase has been used for patients with a bladder-drained pancreas. An increase in serum amylase and lipase has been utilized as an in vivo measure of pancreas rejection in patients with enteric pancreatic exocrine drainage. Decreases in urinary amylase or increases in serum amylase or lipase, respectively, in these two different types of surgical drainage would prompt a pancreas biopsy for histologic confirmation of rejection. Herein, we describe the case of an enteric-drained pancreatic transplant recipient who presented with peripheral eosinophilia at least one month before she developed increases in serum amylase and lipase. A pancreas allograft biopsy indicated eosinophilic acute cellular rejection. Peripheral eosinophilia may be a useful early indicator of pancreas graft rejection preceding changes in serum pancreatic enzymes by approximately one month.

Banff schema for grading pancreas allograft rejection: working proposal by a multi-disciplinary international consensus panel

Accurate diagnosis and grading of rejection and other pathological processes are of paramount importance to guide therapeutic interventions in patients with pancreas allograft dysfunction. A multi-disciplinary panel of pathologists, surgeons and nephrologists was convened for the purpose of developing a consensus document delineating the histopathological features for diagnosis and grading of rejection in pancreas transplant biopsies. Based on the available published data and the collective experience, criteria for the diagnosis of acute cell-mediated allograft rejection (ACMR) were established. Three severity grades (I/mild, II/moderate and III/severe) were defined based on lesions known to be more or less responsive to treatment and associated with better- or worse-graft outcomes, respectively. The features of chronic rejection/graft sclerosis were reassessed, and three histological stages were established. Tentative criteria for the diagnosis of antibody-mediated rejection were also characterized, in anticipation of future studies that ought to provide more information on this process. Criteria for needle core biopsy adequacy and guidelines for pathology reporting were also defined. The availability of a simple, reproducible, clinically relevant and internationally accepted schema for grading rejection should improve the level of diagnostic accuracy and facilitate communication between all parties involved in the care of pancreas transplant recipients.

Pancreas graft drainage in recipient duodenum: preliminary experience

Pancreas graft survival has continuously improved over the years to become a main treatment option of uncontrolled complicated diabetes. Rejection remains the major challenge as it often goes unnoticed until severe damage of the graft manifests itself by elevated blood sugar. Pancreas enzymes monitoring in the blood and in the urine is a sensitive marker of rejection but lack of specificity. Biopsy remains the gold standard. Cystoscopy-guided biopsy of bladder-drained pancreas has a good success rate for obtaining tissue but the vesical drainage exposes to metabolic and urologic morbidity. Percutaneous pancreas biopsy can be performed with a low morbidity rate but severe complications can occur. We discuss a technique of pancreas transplantation with the drainage of exocrine secretions of the pancreatic graft in the recipient duodenum, which permits easy monitoring of the graft by upper endoscopy of the duodenum.

Spectrum of Histopathological Changes in Pancreas Allograft Biopsies and Relationship to Graft Loss

Histological evaluation of pancreas allografts through the use of needle biopsies is of paramount importance for the determination of the etiology of graft dysfunction. In addition, pathological assessment of the overall status of the exocrine, endocrine, and vascular components provides invaluable information with regards to the prognosis of the graft. Pancreas allograft failure results from a variety of causes, highly dependent on the time posttransplantation, but after the first 6 months' posttransplantation the most common cause of graft loss is chronic rejection. The main histological manifestations of chronic rejection are progressive graft sclerosis (increasing fibrosis and proportional atrophy of the glandular components), secondarily leading to endocrine failure. Evaluation of serial biopsies in patients with graft failure has shown that the most important histological predictors of chronic rejection/graft sclerosis are diffuse acinar inflammation and acute and chronic vascular injury in the form of intimal arteritis and proliferative transplant arteriopathy, respectively.

Modified multivisceral transplantation with splenopancreatic preservation

A common requirement of multivisceral transplantation has been removal of the native duodenum, pancreas and spleen in the process of abdominal exenteration. Oftentimes, though, the indication for their removal has not been underlying disease states in those organs. In order to avoid adverse sequelae of pancreas and splenic removal for purely anatomic reasons, we have designed a new approach and have performed a multivisceral transplantation with splenopancreatic preservation. In this modified multivisceral technique, the native spleen and pancreas are preserved with venous outflow through a native portocaval shunt, and native pancreatic exocrine drainage is established to the donor jejunum. Risk of transplant pancreatic insufficiency, posttransplant lymphoproliferative disorder, and postsplenectomy sepsis may be avoided utilizing this technique. This new modification of multivisceral transplantation allows pancreaticosplenic preservation while facilitating stomach replacement for those patients requiring intestinal replacement therapy. It represents another step towards minimizing morbidities associated with these lifesaving transplants.

Influence of pancreas transplantation alone on native renal function

Pancreas transplantation alone (PTA) has become an accepted treatment of nonuremic diabetic patients, when the risks of secondary complications of diabetes mellitus are greater than those of the surgical procedure and the posttransplant immunosuppression. As a decrease in native renal function is expected, we followed this parameter among patients who underwent PTA. From January 1997 through January 2005, we performed 69 PTA in 66 patients. All patients showed glucose hyperlability with hypoglycemic unawareness, or two or more diabetic complications as well as creatinine clearance (CrCl) > or = 45 mL/min. Immunosuppression was based on tacrolimus, mycophenolate mofetil and prednisone. Twenty-four hour CrCl were performed after all successful PTA. We divided patients in two groups according to the pretransplant CrCl: group 1, CrCl < or = 70 mL/min (n = 20) and group 2, CrCl > 70 mL/min (n = 25). The data were analyzed using Student's t-test (P < or = .05 was considered significant). Twenty-one patients were excluded from the analysis because of death (n = 5) or graft loss (n = 8) during the first year or follow-up shorter than 1 year (n = 8). The mean value of CrCl decreased 28.8% (85.0 +/- 31 versus 60.5 +/- 36 mL/min; P < .001). There was also a 39.3% reduction among group 1 subjects (P = .003), including 10 who displayed CrCl < or = 30 mL/min. There was also a 24.4% reduction among group 2 (P = .008), but no patient developed end-stage renal disease. In conclusion, native renal function decreased significantly after PTA, but was well tolerated among patients with CrCl > 70 mL/min. Patients with CrCl < 70 mL/min show a significant risk of worsened renal function.

Ninety-Five Percent Insulin Independence Rate 3 Years After Pancreas Transplantation Alone With Portal-Enteric Drainage

AIMS

Portal-enteric drainage (PED) might be particularly suitable for pancreas transplantation alone (PTA), since it has been associated with an immunologic advantage and achieves excellent metabolic results. We describe our experience with a consecutive series of 40 PTAs with PED.

METHODS

Between April 2001 and March 2004, 40 consecutive PTAs were performed with PED. Recipients were selected according to the American Diabetic Association recommendations. Donors were selected according to standard criteria irrespective of HLA match, although matching for A and B loci was considered at the time of graft allocation. Immunosuppression consisted of induction treatment with basiliximab (n = 34) or thymoglobulin (n = 6), and maintenance therapy with steroids, mycophenolate mofetil, and tacrolimus.

RESULTS

After a mean cold ischemia time of 690 minutes (range, 517-965 min) all pancreases functioned immediately. Three grafts were lost due to hyperacute or accelerated rejection. No graft was lost to vascular thrombosis, although 5 (12.5%) nonocclusive thromboses were identified and the grafts were rescued with intravenous heparin infusion. A repeat laparotomy was required in 7 recipients (17.5%) No patient required multiple repeat laparotomies, and none died. After a mean follow-up of 16.4 months (range, 1-36 mo), 2 recipients were diagnosed with rejection episodes, which were reversed with steroid boluses. Actuarial 3-year patient, and graft survival rates were 100% and 94.9%, respectively. The following parameters showed significant improvement compared with pretransplantation evaluation: hemoglobin A1C concentration, total and high-density lipoprotein cholesterol levels, arterial blood pressure, cardiac performance, retinopathy, proteinuria, and neuropathy.

CONCLUSIONS

Pancreas transplantation alone with PED provides high rates of long-term insulin-independence.

Interventional procedures in whole organ and islet cell pancreas transplantation

Pancreas organ transplantation has been a therapeutic option for the treatment of diabetes mellitus for over a decade. More recently, percutaneous injection of isolated pancreas islet cells via the portal vein has been developed as an exciting minimally invasive alternative procedure to whole organ transplantation, and one where the interventional radiologist may play a major role. This chapter reviews the role of image guided intervention in the whole organ pancreas transplant and describes the evolving technique of percutaneous islet cell transplantation.

Pancreatic transplantation: Beta cell replacement

Diabetes is a leading cause of morbidity and mortality worldwide. Complications of diabetes including renal failure, retinopathy, neuropathy, and cardiovascular disease limit both survival and quality of life. Pancreatic transplantation can restore euglycemia thereby stabilizing or even reversing secondary complications of diabetes as well as improving quality of life particularly in patients with labile diabetes. Recent evidence also shows an improved survival in diabetic patients that undergo pancreatic transplantation when combined with a kidney transplant. Pancreatic transplantation should more properly be referred to as beta cell replacement as the field today encompasses both whole organ and islet cell transplantation. We have outlined herein the indications and contraindications to islet or whole organ pancreas transplantation and we have described periprocedure care and short- and long-term prognosis.

[Pancreatic transplantation: 1. Indications and results]

In the face of a rising incidence of diabetes, pancreatic transplantation seems to be the only treatment capable of normalizing glycosylated hemoglobin and stabilizing or improving the complications of diabetes. To date, more than 19,000 pancreatic transplantations have been done worldwide. Surgical indications must take into account the constraints and risks specific to the diabetic illness, the risks of a complex surgical procedure, and the absolute necessity for long term immunosuppression. Combined kidney/pancreas transplantation is the most common procedure (90% of cases) and is the most effective treatment for renal insufficiency due to diabetes. Results have improved significantly over the last ten Years due to improvements in the surgical technique and to improvement of immunosuppressive regimens. Results are at least as good and perhaps better than those achieved in the transplantation of other solid organs; patient survival, renal graft survival, and pancreatic graft survival are respectively 95%, 92%, and 85% at one Year. Results of pancreatic transplantation alone have improved and now seem equal to those of combined organ transplantation. Transplantation seems to be cost-effective in the overall care of advanced diabetes, particularly in those patients on chronic dialysis or having degenerative complications.

Advances in pancreas transplantation

Despite early obstacles impacting the success of pancreatic transplantation, the introduction of new procedures and new immunosuppressive therapies during the past 2 decades has improved outcomes for pancreatic transplant recipients. For example, the use of bladder drainage and better human leukocyte antigen matching has helped overcome some of the early obstacles of pancreatic transplantation. In addition, the introduction of tacrolimus in 1994 and mycophenolate mofetil in 1996 has helped lower rates of acute rejection and increase graft survival, with less nephrotoxicity than treatment with cyclosporine. Regimens allowing the tapering of corticosteroids have also helped reduce the rates of acute pancreas rejection. To further improve therapeutic options for patients with type 1 diabetes or end-stage renal disease, pancreatic islet transplantation and organ and islet xenotransplantation should be further explored.

Portal enteric–drained solitary pancreas transplantation without surveillance biopsy: is it safe?

BACKGROUND

Most solitary pancreas transplants (SPTx) fail due to unrecognized rejection episodes. Consequently, SPTx are monitored by drainage into the bladder or by surveillance biopsies.

METHODS

Between April 2001 and June 2003, a consecutive series of 48 SPTx were performed using portal enteric drainage (PED). Rejection episodes were diagnosed empirically, based on the elevated pancreatic enzymes without a surveillance biopsy. Immunosuppression consisted of basiliximab (n = 42) or ATG (n = 6), low-dose steroids, MMF, and tacrolimus. Donors (mean age 28.9 year; range 9 to 54 year) were selected according to standard criteria irrespective of HLA match, although the best HLA matching was considered at the time of graft allocation.

RESULTS

After a mean cold ischemia time of 676 minutes (range 475 to 900 minutes), all but two pancreata (95.8%) functioned immediately. Relaparotomy was required in seven cases (14.6%). Three grafts were lost in the early posttransplant period due to hyperacute rejection. Two additional grafts were lost later due to arterial thrombosis or to chronic rejection. After a median follow-up period of 12.2 months (range 0.2 to 27 months) three further recipients were diagnosed with rejection episodes that were reversed with steroid boluses. Actuarial 1-year patient and graft survival rates were 100% and 93.1% and 2-year figures 100% and 88.7%, respectively. At the longest follow-up no recipient was diagnosed with a malignancy.

CONCLUSIONS

With current immunosuppression protocols SPTx achieves high rates of insulin independence even without surveillance biopsy or routine use of T-cell-depleting therapies.

Simultaneous cadaver pancreas–living donor kidney transplantation

BACKGROUND

The expansion of the donor pool achieved with living kidney donation (LKD) is particularly beneficial for diabetic patients, who have a worse prognosis during dialysis when compared to other kidney recipients. Simultaneous cadaver pancreas-living kidney transplantation (SPLKTx) merges the advantages of LKD with those of cadaver donation, and may be an attractive alternative to simultaneous pancreas kidney transplantation (SPKTx).

METHODS

The outcomes of 18 SPLKTx were compared with those of 33 SPKTx.

RESULTS

LKD expanded the donor pool from 33 to 51 (P =.004). Median wait time was shorter for SPLKTx (14 days) than for SPKTx (95 days) (P =.006). The risk for surgical complications was not increased by SPLKTx, as witnessed by relaparotomy rates (SPLKTx: 2/18, 11.1%; SPKTx: 2/33, 6.1%; P >.05). Hospital stay averaged 26.1 +/- 11.2 days for SPLKTx and 27.1 +/- 16.3 for SPKTx (P >.05) with equivalent 30-day readmission rates (SPLKTx: 5.5%; SPKTx: 6.1%); (P >.05). One acute kidney rejection occurred in SPLKTx (5.5%) as compared with four in SPKTx (12.1%); (P >.05). Equivalent rates for the pancreas were 5.5% (1/18) for SPLKTx and 3.0% (1/33) for SPKTx (P >.05). Two-year recipient survival rates were 100% for SPLKTx as compared with 96.9% for SPKTx. Equivalent figures for kidney and pancreas were 80.0% and 84.0% for SPLKTx and 96.9% and 96.9% for SPKTx.

CONCLUSIONS

SPLKTx is a valuable alternative to SPKTx. Further development of SPLKTX relies on increased rates of living kidney donation.

Pancreas-after-kidney transplantation: an increasingly attractive alternative to simultaneous pancreas-kidney transplantation

BACKGROUND

Historically, the clinical acceptability of pancreas-after-kidney (PAK) transplantation has been hampered by relatively high acute rejection rates and lower pancreas graft survival rates when compared with the more commonly performed simultaneous pancreas-kidney (SPK) transplantation. The purpose of this study was to compare PAK transplantation to SPK transplantation in the Thymoglobulin induction era.

METHODS

The authors reviewed all bladder-drained PAK (n=47) transplants receiving rabbit antithymocyte globulin induction from June 1998 to June 2002 and compared them with SPK (n=25) transplants during the same time period at their institution. The authors retrospectively studied data on demographics, patient survival, graft (pancreas and kidney) survival, complications, and biopsy-proven rejection episodes.

RESULTS

The actuarial 1-year patient survival was 93% for the PAK group versus 100% for the SPK group (P =not significant [NS]). The actuarial 1-year pancreas graft survival was 87% for the PAK group versus 92% for the SPK group (P =NS). Waiting time for PAK was significantly shorter than for SPK (6.3 +/- 5.2 vs. 16.2 + -13.7 months, P <0.05). Clinical acute rejection rates were similar in the two groups (4.3% for PAK vs. 4.0% for SPK). PAK recipients demonstrated a greater decline in renal function after transplantation compared with SPK. A multivariate analysis failed to elucidate the cause.

CONCLUSIONS

Newer immunosuppressive regimens allow PAK transplant patients to achieve immunologic outcomes similar to SPK transplant patients. Although the shorter waiting time and the ability to use living-donor kidneys make PAK an increasingly attractive alternative to SPK transplantation, its effect on renal allograft function deserves further attention.

Clinical islet transplant: current and future directions towards tolerance

The ultimate goal of islet transplantation is to completely correct the diabetic state from an unlimited donor source, without the need for chronic immunosuppressive drug therapy. Although islet transplantation provides an opportunity to develop innovative strategies for tolerance in the clinic, both alloimmune and autoimmune barriers must be controlled, if stable graft function is to be maintained long-term. After islet extraction from the pancreas, the cellular graft may be stored in tissue culture or cryopreserved for banking, providing an opportunity not only to optimally condition the recipient but also to allow in vitro immunologic manipulation of the graft before transplantation, unlike solid organ grafts. As such, islets may be considered a "special case." Remarkable progress has occurred in the last three years, with dramatic improvements in outcomes after clinical islet transplantation. The introduction of a steroid-free, sirolimus-based, anti-rejection protocol and islets prepared from two (or rarely three) donors led to high rates of insulin independence. The "Edmonton Protocol" has been successfully replicated by other centers in an international multicenter trial. A number of key refinements in pancreas transportation, processing, purification on non-ficoll-based media, storage of islets in culture for two days and newer immunological conditioning and induction therapies have led to continued advancement through extensive collaboration between key centers. This review outlines the historical development of islet transplantation over the past 30 years, provides an update on current clinical outcomes, and summarizes a series of unique opportunities for development and early testing of tolerance protocols in patients.

Histological grading of chronic pancreas allograft rejection/graft sclerosis

Chronic rejection (CR) of pancreas allografts needs to be accurately defined and diagnosed. We propose a grading scheme designed for percutaneous needle biopsies (C0-CIII). Grading is based on the semi-quantitative determination of fibrosis and corresponding proportional loss of exocrine parenchyma. Pancreas biopsies (n = 141) from 46 patients were studied. Twenty-six patients lost graft function after a mean time of 25.5 months, whereas 20 patients retained good graft function during a mean follow-up of 67.7 months. Sequential biopsies showed gradual progression of CR over time (p = 0.0001), and good correlation was found between the CR grade and the time elapsed from transplantation (p = 0.0001). The CR grade was predictive of the remaining time of graft function (54.3 months for C0, 24.6 months for CI, 9.7 months for CII and 1.6 months for CIII p = 0.00001). Preceding episodes of acute rejection (AR) were more frequent and more severe, and often occurred late in patients with graft loss due to CR (p = 0.04). Reproducibility among pathologists from different institutions was excellent for grades C0 (Kappa 0.9) and CIII (0.87), substantial for Grade CII (0.61) and moderate for Grade CI (0.59). The proposed grading scheme provides a reliable and reproducible tool for the assessment of CR in percutaneous needle biopsies, with definite prognostic significance.

Improving results in solitary pancreas transplantation with portal-enteric drainage, thymoglobin induction, and tacrolimus/mycophenolate mofetil-based immunosuppression

Advances in surgical techniques and clinical immunosuppression have led to steadily improving results in pancreas transplantation (PTX). The purpose of this study was to analyze retrospectively the outcomes in patients undergoing solitary PTX with portal-enteric (P-E) drainage and contemporary immunosuppression. From June 1998 through December 2000, we performed 28 solitary PTXs with antibody induction and tacrolimus/mycophenolate mofetil maintenance therapy. The first 13 patients received daclizumab (DAC) induction, while the next 15 received thymoglobulin (rabbit anti-human thymocyte gamma globulin; Thymo) induction. The study group included 13 pancreas alone (PA) and 15 sequential pancreas-after-kidney-transplantations (PAKT). Solitary PTX was performed with P-E drainage in 18 patients and systemic-enteric (S-E) drainage in ten. Patient and pancreas graft survival rates were 96% and 79%, respectively, with a mean follow-up of 22 (range 1-39) months. The 1-year actual death-censored pancreas graft survival rate was 89%. One PAKT patient died with a functioning graft at 1 month; three patients (11%) experienced early graft loss due to thrombosis and were excluded from the immunological analysis, leaving 24 evaluable patients. The incidence of acute rejection was 54%, including 50% in PA and 58% in PAKT recipients ( P=NS). In patients receiving Thymo induction, the rate of acute rejection was slightly lower (43% Thymo vs 70% DAC). Moreover, P-E drainage was associated with a slightly lower rate of acute rejection (44% P-E vs 75% S-E; P=NS). In patients with both Thymo induction and P-E drainage ( n=11), there was a tendency toward less rejection (the incidence of acute rejection was 36%). Two immunological graft losses occurred (one due to non-compliance), both in patients with P-E drainage. Only one patient had a cytomegalovirus (CMV) infection. Event-free survival (no rejection, graft loss, or death) was slightly higher in patients receiving Thymo (47%) than in those on DAC (23%) induction ( P=NS). We can conclude that solitary PTX with P-E drainage and Thymo induction may be associated with improved intermediate-term outcomes and a possible immunological advantage.

Pancreas and islet cell transplantation

Currently, for the patient with type 1 diabetes, a definitive treatment without resorting to the use of exogenous insulin can be achieved only with pancreas or islet cell transplantation. These means of restoring beta-cell mass can completely maintain essentially normal long-term glucose homeostasis, although the need for powerful immunosuppressive regimens limits their application to only a subgroup of adult patients. Apart from the shortage of donors that has limited all kinds of transplantation, however, the widespread use of beta-cell replacement has been precluded until recently by the drawbacks associated with both organ and islet cell transplantation. Although the study of recurrence of diabetes has generated attention, the fundamental obstacle to pancreas and islet transplantation has been, and remains, the alloimmune response. With a better elucidation of the mechanisms of alloengraftment achieved during the last 3 years, the stage has been set for further advances.

Pancreas allograft biopsy: safety of percutaneous biopsy-results of a large experience

BACKGROUND

Percutaneous pancreas allograft biopsy is the technique of choice for evaluation of pancreatic allograft rejection or dysfunction. The safety and success rate of the procedure with current surgical techniques is unclear. We report the complications and success rate in 426 consecutive percutaneous pancreas allograft biopsies performed at a single center.

METHODS

One hundred eighty-three patients (50% simultaneous pancreas-kidney transplant, 42% pancreas after kidney transplant, 8% pancreas transplant alone) were biopsied. Biopsies were performed using an 18-gauge automated needle with ultrasound guidance.

RESULTS

Thirty-seven patients had four or more biopsies (maximum, 11). Two hundred fifteen (50%) biopsies were in patients with bladder exocrine drainage, 211 (50%) in patients with enteric exocrine drainage. Of the latter, 33 (16%) were in patients with portal venous drainage. Eighty-eight percent of biopsy specimens were adequate for histologic diagnosis. There were 12 biopsy-related complications (2.8%), including eight episodes of bleeding (1.9%), five of which (1.2%) required surgical intervention and one possible extra-graft exocrine leak. Other complications included inadvertent liver (1), kidney (1), and small bowel (1) biopsy.

CONCLUSIONS

Percutaneous pancreas allograft biopsy has a low rate of complication and a high success rate.

Pancreas after kidney transplants in posturemic patients with type I diabetes mellitus

Pancreas after previous kidney (PAK) transplants are an attractive option for type 1 diabetic patients because of the short waiting time and use of living kidney donors. Factors associated with the increased success rate of PAK transplants in four immunosuppressive eras were analyzed. Between July 1, 1978, and April 30, 2000, 406 PAK transplants were performed in posturemic patients. Four immunosuppressive eras were analyzed: (1) the precyclosporine era, era 1 (n = 65; 16%); (2) the cyclosporine era, era 2 (n = 109; 27%); (3) the tacrolimus era with monoclonal or polyclonal antibody induction therapy, era 3 (n = 104; 26%); and (4) the tacrolimus era with monoclonal and polyclonal antibody induction therapy, era 4 (n = 128; 31%). Patient and graft survival, rejection, and technical failure rates were calculated. Patient survival rates have remained high over time, from 91% (era 1) to 96% (era 4) at 1 yr posttransplant. Pancreas graft survival rates with primary cadaver transplants have significantly increased, from 17% (era 1) to 81% (era 4) at 1 yr. The rate of graft loss from rejection has significantly decreased, from 78% (era 1) to 9% (era 4) at 1 yr. Results were best when donors and recipients were matched for at least one antigen per HLA locus. Kidney graft survival was higher in PAK transplant recipients compared with diabetic recipients of kidney transplants alone from the time of the kidney as well as the pancreas transplants. PAK recipients now enjoy >80% graft survival at 1 yr. This improvement in outcome results from better immunosuppression, good matching, and close posttransplant monitoring for rejection.

Superiority of portal venous drainage over systemic venous drainage in pancreas transplantation: a retrospective study

OBJECTIVE

To compare portal and systemic venous drainage of pancreas transplants and demonstrate an immunologic and survival superiority of portal venous drainage.

SUMMARY BACKGROUND DATA

Traditionally, solitary pancreas transplants have been performed using systemic venous and bladder drainage, but more recently, the advantages of enteric drainage have been well documented. Although physiologic benefits for portal venous drainage have been described, the impact of portal venous drainage, especially with solitary pancreas transplants, has yet to be determined.

METHODS

Since August 1995, 280 pancreas transplants with enteric duct drainage were analyzed. One hundred and seventeen were simultaneous pancreas and kidney (SPK), 63 with systemic venous drainage (SV) and 54 with portal venous drainage (PV). The remainder were solitary transplants; 97 pancreas after kidney (PAK; 42 SV and 55 PV) and 66 transplants alone (PTA; 26 SV and 40 PV). Immunosuppressive therapy was equivalent for both groups.

RESULTS

The groups were similar with respect to recipient characteristics and HLA matching. Thirty-six month graft survival for all transplants was 79% for PV and 65% for SV (P =.008). By category, SPK graft survival was 74% for PV and 76% for SV, PAK graft survival was 70% for PV and 56% for SV, and PTA graft survival was 84% for PV and 50% for SV. The rate of at least one rejection episode was also significantly higher in the SV group. At 36 months, for all pancreas transplants, the rejection rate was 21% for PV and 52% for SV (P <.0001). For SPK, rejection rates were 9% for PV and 45% for SV. For PAK, rejection rates were 16% for PV and 65% for SV, and for PTA 36% for PV and 51% for SV. The rejection rates for kidneys following SPK were also lower in the PV group (26% versus 43% for SV). Furthermore, the grades of rejection were milder in PV for all transplants (P =.017). By multivariate analysis, portal venous drainage was the only parameter that significantly affected rejection.

CONCLUSION

Graft survival and rejection is superior for PV. These clinical findings are consistent with published reports of experimentally induced portal tolerance and strongly argue that PV drainage should be the procedure of choice for pancreas transplantation.

Pancreas transplantation in Ohio: a 15-year outcomes analysis

BACKGROUND

Beginning in 1984, all pancreas transplantations performed in the state of Ohio have been tracked by the Ohio Solid Organ Transplantation Consortium (OSOTC). In this study the outcomes of these transplantations were compared across 3 eras to determine whether increasing experience has been beneficial.

METHODS

Between July 1984 and December 1999, 765 kidney-pancreas (KPTx) and 76 pancreas only (Ptx) transplantations were performed. Outcomes measures for these 841 pancreas transplantations were compared over 3 eras, 1984 to 1989, 1990 to 1994, and 1995 to 1999.

RESULTS

One-year patient survivals for KPTx patients were 87%, 92%, and 94% in the 3 eras, respectively. Graft survival at 1 year was also markedly improved between era 1 and era 3, increasing for PTx patients from 21% to 85% and for KPTx patients from 68% to 85%. Average waiting time increased from 132 to 318 days between era 1 and era 3. Conversely, average length of stay in hospital was significantly decreased from 34 to 18 days. The cost of the procedure, as measured by hospital charges, also decreased when compared in 1985 dollars as a technique to control for inflation.

CONCLUSIONS

These data suggest that pancreas transplantation in Ohio has become a very successful and cost-effective therapeutic intervention for patients with type I diabetes with or without concomitant end-stage renal failure.

Comparison of azathioprine and mycophenolate mofetil for the prevention of acute rejection in recipients of pancreas transplantation

The study was performed to compare the efficacy and side effects of azathioprine (AZA) and mycophenolate mofetil (MMF) in conjunction with cyclosporine or tacrolimus and steroids for the prevention of acute pancreas rejection during the first 6 months of pancreas transplantation. In this case-controlled study, MMF is compared with historical controls of AZA in the prevention of acute pancreas rejection. The primary measures of treatment efficacy were patient and pancreas survival rate at 6 months after transplantation. Secondary efficacy measures were the occurrence of biopsy-proven pancreas rejections and the use of antilymphocyte preparations for rejection treatment. A total of 111 pancreas transplant patients (57 in the AZA group and 54 in the MMF group) were evaluated. The 6-month patient survival rate was 96% in the AZA group versus 97% in the MMF group (p = 0.57). The 6-month pancreas graft survival rate was 88% in the AZA group versus 91% in the MMF group (p = 0.29). However, biopsy-proven rejection episodes during the first 6 months of transplantation were significantly lower with MMF (46%) than with AZA (69%) (p = 0.01). In addition, patients in the AZA group received a greater number of full courses of antilymphocyte therapy as a rejection treatment (p = 0.004). Overall, the frequency of adverse events was similar, although the MMF group experienced higher incidences of gastrointestinal adverse events. In conclusion, compared with AZA, MMF significantly reduces the rate of biopsy-proven pancreas rejection during the first 6 months of transplantation and is well tolerated, except for gastrointestinal adverse events.

Novel approaches toward early diagnosis of islet allograft rejection

BACKGROUND

The inability to diagnose early rejection of an islet allograft has previously proved to be a major impediment to progress in clinical islet transplantation. The need to detect early rejection will become even more relevant as new tolerance-inducing protocols are evaluated in the clinic. We explored three novel approaches toward development of early diagnostic markers of islet rejection after islet allotransplantation.

METHODS

(a) Canine islet allograft transplant recipients were immunosuppressed for 1 month, then therapy was withdrawn. Serum glutamic acid decarboxylase antigen (GAD65), an endogenous islet protein, was monitored daily with a CO2 release assay. (b) Rodent islets were genetically engineered to express a unique foreign protein (beta-galactosidase) by using adenoviral vectors, and after allograft transplantation, the viral-specific protein was measured in serum using optical luminescence. (c) Rodents receiving islet allografts were immunosuppressed temporarily, and daily glucose tolerance tests were followed until graft failure occurred.

RESULTS

(a) Although serum monitoring of GAD65 antigen demonstrated elevated levels preceding loss of graft function in preliminary studies, the effect was not reproducible in all animals. (b) Genetically engineered rodent islets demonstrated normal insulin kinetics in vitro (insulin stimulation index 2.57+/-0.2 vs. 2.95+/-0.3 for control islets, P=ns), and purified viral protein products had a stable half-life of 8 hr in vivo. After islet allotransplantation, there were two peak elevations in serum viral proteins, confirming that an intra-islet "sentinel signal" could be detected serologically during acute rejection. There was no lead-time ahead of hyperglycemia, however. (c) Daily sequential intravenous glucose tolerance (IVGT) tests demonstrated evidence of allograft dysfunction (decline in KG) with a 2-day lead time to hyperglycemia (2.58+/-0.3 vs. 1.63+/-0.2%/min, respectively, P<0.001), with an accuracy of 89%, sensitivity of 78%, and specificity of 95%.

CONCLUSIONS

Of the three diagnostic tests, metabolic assessment with an abbreviated IVGT was the most effective method of demonstrating early islet dysfunction due to rejection.

Pancreas transplantation: the histologic morphology of graft loss and clinical correlations

BACKGROUND

Graft losses due to leaks, bleeding, thrombosis, infections, and early pancreatitis are grouped together under the category of technical failure. Among these complications, massive vascular thrombosis continues to be the most important cause of early graft loss due to technical failure. Pathological evaluation of most allografts lost early in the posttransplantation period shows vascular thrombosis with associated proportional parenchymal necrosis. The morphological findings in allografts that are considered to be lost due to technical failure has not been systematically addressed. In particular, the role of acute rejection in early graft loss has not been well studied.

METHODS

Seventy-four consecutive pancreas graft pancreatectomies were studied histologically to evaluate for thrombosis (recent versus organized), type of vessel involved by thrombosis (arteries, veins, or both), acute rejection grade, chronic rejection grade, endotheliitis, transplant arteritis, coagulation necrosis, acute pancreatitis, presence of infectious organisms, transplant (obliterative) arteriopathy, neoplasia, relative proportions of alpha and beta islet cells, and immunoglobulin and complement deposition. The histological findings were correlated with donor and recipient data as well as clinical presentation.

RESULTS

In 23 out of 39 grafts lost in the first 4 weeks posttransplantation, the only pathological changes found were vascular thrombosis and bland ischemic parenchymal necrosis. In these cases, no underlying vascular pathology or any other specific histological change was identified. Most of these grafts (78%) were lost in less than 48 hr and all in the first 2 weeks posttransplantation. Massive vascular thrombosis occurring in an otherwise histologically normal pancreas was the most common cause of graft loss in the first 4 weeks posttransplantation (59%). In most of the remaining cases (33%), although the clinical presentation suggested technical failure, there was clear histological evidence that the massive thrombosis resulted from vascular injury due to immune damage (acute and hyperacute rejection). Increased incidence of early graft thrombosis was seen in grafts from older donors and longer cold ischemia times. After the first month posttransplantation, graft pancreatectomies revealed a wider variety of pathological processes that included severe acute rejection, combined acute and chronic rejection, chronic rejection, and infections. Acute and chronic vascular thrombosis in large and small vessels was commonly seen at all times posttransplantation; chronic, organized thrombosis was strongly associated with chronic rejection.

CONCLUSIONS

(a) Early acute thrombosis occurring in a histologically normal pancreas defines a true technical failure. This study showed that acute rejection leading to massive thrombosis, which clinically simulates technical failure, results in a significant proportion of early graft losses. (b) Systematic histological evaluation of failed grafts is absolutely necessary for the accurate classification of the cause of graft loss. (c) There is morphological evidence that chronically ongoing thrombosis is an important, common, contributing factor for late graft loss.

Pancreatic islet transplantation in the treatment of diabetes mellitus

This chapter reviews current developments and future directions in clinical islet transplantation. With the recent introduction of glucocorticoid-free immunosuppressive therapies and improved methods for islet isolation, the success of the procedure has increased substantially. Challenges ahead include progress with international multicentre trials, development of single donor protocols, progress in clinical tolerance based therapies to lower overall risk of immunosuppression, and ultimately finding an alternative source to provide effective therapy for more patients with diabetes. Recent advances in stem cell biology and xenotransplantation may soon provide this opportunity.

Lessons learned from more than 1,000 pancreas transplants at a single institution

OBJECTIVE

To determine outcome in diabetic pancreas transplant recipients according to risk factors and the surgical techniques and immunosuppressive protocols that evolved during a 33-year period at a single institution.

SUMMARY BACKGROUND DATA

Insulin-dependent diabetes mellitus is associated with a high incidence of management problems and secondary complications. Clinical pancreas transplantation began at the University of Minnesota in 1966, initially with a high failure rate, but outcome improved in parallel with other organ transplants. The authors retrospectively analyzed the factors associated with the increased success rate of pancreas transplants.

METHODS

From December 16, 1966, to March 31, 2000, the authors performed 1,194 pancreas transplants (111 from living donors; 191 retransplants): 498 simultaneous pancreas-kidney (SPK) and 1 simultaneous pancreas-liver transplant; 404 pancreas after kidney (PAK) transplants; and 291 pancreas transplants alone (PTA). The analyses were divided into five eras: era 0, 1966 to 1973 (n = 14), historical; era 1, 1978 to 1986 (n = 148), transition to cyclosporine for immunosuppression, multiple duct management techniques, and only solitary (PAK and PTA) transplants; era 2, 1986 to 1994 (n = 461), all categories (SPK, PAK, and PTA), predominantly bladder drainage for graft duct management, and primarily triple therapy (cyclosporine, azathioprine, and prednisone) for maintenance immunosuppression; era 3, 1994 to 1998 (n = 286), tacrolimus and mycophenolate mofetil used; and era 4, 1998 to 2000 (n = 275), use of daclizumab for induction immunosuppression, primarily enteric drainage for SPK transplants, pretransplant immunosuppression in candidates awaiting PTA.

RESULTS

Patient and primary cadaver pancreas graft functional (insulin-independence) survival rates at 1 year by category and era were as follows: SPK, era 2 (n = 214) versus eras 3 and 4 combined (n = 212), 85% and 64% versus 92% and 79%, respectively; PAK, era 1 (n = 36) versus 2 (n = 61) versus 3 (n = 84) versus 4 (n = 92), 86% and 17%, 98% and 59%, 98% and 76%, and 98% and 81%, respectively; in PTA, era 1 (n = 36) versus 2 (n = 72) versus 3 (n = 30) versus 4 (n = 40), 77% and 31%, 99% and 50%, 90% and 67%, and 100% and 88%, respectively. In eras 3 and 4 combined for primary cadaver SPK transplants, pancreas graft survival rates were significantly higher with bladder drainage (n = 136) than enteric drainage (n = 70), 82% versus 74% at 1 year (P =.03). Increasing recipient age had an adverse effect on outcome only in SPK recipients. Vascular disease was common (in eras 3 and 4, 27% of SPK recipients had a pretransplant myocardial infarction and 40% had a coronary artery bypass); those with no vascular disease had significantly higher patient and graft survival rates in the SPK and PAK categories. Living donor segmental pancreas transplants were associated with higher technically successful graft survival rates in each era, predominately solitary (PAK and PTA) in eras 1 and 2 and SPK in eras 3 and 4. Diabetic secondary complications were ameliorated in some recipients, and quality of life studies showed significant gains after the transplant in all recipient categories.

CONCLUSIONS

Patient and graft survival rates have significantly improved over time as surgical techniques and immunosuppressive protocols have evolved. Eventually, islet transplants will replace pancreas transplants for suitable candidates, but currently pancreas transplants can be applied and should be an option at all stages of diabetes. Early transplants are preferable for labile diabetes, but even patients with advanced complications can benefit.

Simultaneous cadaver pancreas living-donor kidney transplantation: a new approach for the type 1 diabetic uremic patient

OBJECTIVE

To review the authors' experience with a new approach for type I diabetic uremic patients: simultaneous cadaver-donor pancreas and living-donor kidney transplant (SPLK).

SUMMARY BACKGROUND DATA

Simultaneous cadaver kidney and pancreas transplantation (SPK) and living-donor kidney transplantation alone followed by a solitary cadaver-donor pancreas transplant (PAK) have been the transplant options for type I diabetic uremic patients. SPK pancreas graft survival has historically exceeded that of solitary pancreas transplantation. Recent improvement in solitary pancreas transplant survival rates has narrowed the advantage seen with SPK. PAK, however, requires sequential transplant operations. In contrast to PAK and SPK, SPLK is a single operation that offers the potential benefits of living kidney donation: shorter waiting time, expansion of the organ donor pool, and improved short-term and long-term renal graft function.

METHODS

Between May 1998 and September 1999, the authors performed 30 SPLK procedures, coordinating the cadaver pancreas transplant with simultaneous transplantation of a laparoscopically removed living-donor kidney. Of the 30 SPLKs, 28 (93%) were portally and enterically drained. During the same period, the authors also performed 19 primary SPK and 17 primary PAK transplants.

RESULTS

One-year pancreas, kidney, and patient survival rates were 88%, 95%, and 95% for SPLK recipients. One-year pancreas graft survival rates in SPK and PAK recipients were 84% and 71%. Of 30 SPLK transplants, 29 (97%) had immediate renal graft function, whereas 79% of SPK kidneys had immediate function. Reoperative rates, early readmission to the hospital, and initial length of stay were similar between SPLK and SPK recipients. SPLK recipients had a shorter wait time for transplantation.

CONCLUSIONS

Early pancreas, kidney, and patient survival rates after SPLK are similar to those for SPK. Waiting time was significantly shortened. SPLK recipients had lower rates of delayed renal graft function than SPK recipients. Combining cadaver pancreas transplantation with living-donor kidney transplantation does not harm renal graft outcome. Given the advantages of living-donor kidney transplant, SPLK should be considered for all uremic type I diabetic patients with living donors.

Improved solitary pancreas transplant graft survival in the modern immunosuppressive era

The results of solitary pancreas (SP) transplantation have traditionally lagged behind those of simultaneous pancreas-kidney (SPK) transplantation. This is one of the chief factors that has limited the wide-scale application of SP transplantation in nonuremic type I diabetic patients. The purpose of this study is to report our present experience with SP transplantation and compare it to a prior experience. Twenty-three SP transplants (14 PAK, 4 PTA, and 5 PASPK) performed since January 1997 were compared to 56 SP transplants (53 PAK, 1 PTA, and 2 PASPK) performed before 1994. Between 1993 and 1997, SP transplants were not performed because of high morbidity in the early experience. Early SP transplants were performed using bladder drainage of exocrine secretions, and enteric drainage without a Roux-en-Y was used in the recent series. In the early era, immunosuppressive therapy included cyclosporine (CsA), azathioprine (AZA), corticosteroids, and in half of the patients, ALG or OKT3. Recent SP transplants received tacrolimus (TAC). mycophenolate mofetil (MMF), corticosteroids, and induction with either anti-thymocyte globulin (n = 9), OKT3 (n = 1), daclizumab (n = 5), or basiliximab (n = 8). The 1-year Kaplan-Meier patient survival was 85% in the early era and 100% in the recent group of patients (p = 0.08). In the previous era, four patients suffered significant decrement in renal function, necessitating dialysis or kidney transplantation following pancreas transplantation. All patients transplanted since 1997 maintain near prepancreas transplant levels of renal function (mean pretransplant serum creatinine (Cr) 1.3 +/- 0.3 mg/dl vs, mean current Cr 1.4 +/- 0.4 mg/dl, p = NS]. The 1-year Kaplan-Meier graft survival (insulin independence) of recent SP transplants was 87%, whereas for prior SP transplants it was 19% (p = 0.0001). The rate of acute pancreas rejection was significantly different between the two groups. Of early SP transplants, 76% experienced at least one rejection episode within the first year. In contrast, 35% of recent SP transplants suffered acute rejection during the same time period (p = 0.04). Current experience with SP transplantation demonstrates improved graft survival and reduced rejection rates with the use of newer immunosuppressive agents.

Islet transplantation in seven patients with type 1 diabetes mellitus using a glucocorticoid-free immunosuppressive regimen

BACKGROUND

Registry data on patients with type 1 diabetes mellitus who undergo pancreatic islet transplantation indicate that only 8 percent are free of the need for insulin therapy at one year.

METHODS

Seven consecutive patients with type 1 diabetes and a history of severe hypoglycemia and metabolic instability underwent islet transplantation in conjunction with a glucocorticoid-free immunosuppressive regimen consisting of sirolimus, tacrolimus, and daclizumab. Islets were isolated by ductal perfusion with cold, purified collagenase, digested and purified in xenoprotein-free medium, and transplanted immediately by means of a percutaneous transhepatic portal embolization.

RESULTS

All seven patients quickly attained sustained insulin independence after transplantation of a mean (+/-SD) islet mass of 11,547+/-1604 islet equivalents per kilogram of body weight (median follow-up, 11.9 months; range, 4.4 to 14.9). All recipients required islets from two donor pancreases, and one required a third transplant from two donors to achieve sustained insulin independence. The mean glycosylated hemoglobin values were normal after transplantation in all recipients. The mean amplitude of glycemic excursions (a measure of fluctuations in blood glucose concentrations) was significantly decreased after the attainment of insulin independence (from 198+/-32 mg per deciliter [11.1+/-1.8 mmol per liter] before transplantation to 119+/-37 mg per deciliter [6.7+/-2.1 mmol per liter] after the first transplantation and 51+/-30 mg per deciliter [2.8+/-1.7 mmol per liter] after the attainment of insulin independence; P<0.001). There were no further episodes of hypoglycemic coma. Complications were minor, and there were no significant increases in lipid concentrations during follow-up.

CONCLUSIONS

Our observations in patients with type 1 diabetes indicate that islet transplantation can result in insulin independence with excellent metabolic control when glucocorticoid-free immunosuppression is combined with the infusion of an adequate islet mass.

Towards a specific immunosuppression for pancreas and islet grafts

This brief article is a summary of the presentations at a meeting organized in Lyon, France, to discuss strategies of reducing post-transplant diabetes mellitus and to suggest an ideal immunosuppressive therapy for pancreatic and islet allografts.