A prospective study of rapid corticosteroid elimination in simultaneous pancreas-kidney transplantation: comparison of two maintenance immunosuppression protocols: tacrolimus/mycophenolate mofetil versus tacrolimus/sirolimus

Impact of early corticosteroid withdrawal on simultaneous pancreas-kidney transplant long-term outcomes: Single center experience and comparison to the International Pancreas Transplant Registry

BACKGROUND

There remains a paucity of modern data comparing early steroid withdrawal (ESW) versus chronic corticosteroid (CCS) immunosuppression in simultaneous pancreas kidney (SPK) transplant recipients with long-term follow-up. Therefore, the purpose of this study is to assess the effectiveness and tolerability of ESW compared to CCS post-SPK.

METHODS

This was a retrospective single-center matched comparison with the International Pancreas Transplant Registry (IPTR). Patients from University of Illinois Hospital (UIH) represented the ESW group and were compared to those matched CCS patients from the IPTR. Included patients were adult recipients of a primary SPK transplant between 2003 and 2018 within the US receiving rabbit anti-thymocyte globulin induction. Patients were excluded if they had early technical failures, missing IPTR data, graft thrombosis, re-transplant, or positive crossmatch SPK.

RESULTS

A total of 156 patients were matched and included in the analysis. Patients were predominantly African American (46.15%) males (64.1%) with Type 1 diabetes etiology (92.31%). Overall pancreas allograft survival (hazard ratio [HR] = .89, 95% confidence interval [CI] .34-2.30, p = .81) and kidney allograft survival (HR = .80, 95%CI .32-2.03, p = .64) were similar between the two groups. Immunologic pancreas allograft loss was statistically similar at 1-year (ESW 1.3% vs. CCS 0%, p = .16), 5-year (ESW 1.3% vs. CCS 7.7%, p = .16), and 10-year (ESW 11.0% vs. CCS 7.7%, p = .99). The 1-year (ESW 2.6% vs. CCS 0%, p > .05), 5-year (ESW 8.3% vs. CCS 7.0%, p > .05), and 10-year (ESW 22.7% vs. CCS 9.9%, p = .2575) immunologic kidney allograft loss were also statistically similar. There was no difference in 10-year overall patient survival (ESW 76.2% vs. CCS 65.6%, p = .63).

CONCLUSIONS

No differences were found between allograft or patient survival post-SPK when comparing an ESW or CCS protocol. Future assessment is needed to determine differences in metabolic outcomes.

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.

Distal allograft pancreatectomy for graft salvage after pancreas transplantation

Early pancreas allograft failure most commonly results from vascular thrombosis. Immediate surgical intervention may permit pancreas allograft salvage, typically requiring thrombectomy. In cases of partial allograft necrosis secondary to splenic arterial thrombosis, distal allograft pancreatectomy may allow salvage of at least half of the pancreas allograft with retention of function. We retrospectively reviewed four cases of simultaneous pancreas and kidney recipients who required distal allograft pancreatectomy for splenic artery thrombosis with necrosis of the distal pancreas. Three of the four maintained long-term allograft function with euglycemia independent of insulin at six months to six years of follow-up, and all patients continue to maintain normal renal allograft function. Early diagnosis and early intervention are essential in order to salvage the pancreas allograft in the case of thrombosis. Distal allograft pancreatectomy can be performed safely and result in excellent long-term outcomes in select patients.

Immunosuppression considerations in simultaneous organ transplant

Solid organ transplantation is a life-saving procedure for patients in the end stage of heart, lung, kidney, and liver failure. For patients with more than one failing organ, simultaneous organ transplantation has emerged as a viable treatment option. Immunosuppression strategies and outcomes for simultaneous organ transplant recipients have been reported, but often involve limited populations. Transplanting dual organs poses challenges in terms of balancing immunosuppression with immunologic risk and allograft damage from surgical complications. Furthermore, transplanting certain organs can impose considerations on the management of immunosuppression. For example, liver allografts may confer immunologic privilege and lower rates of rejection of other allografts. This review article evaluates immunosuppression strategies for simultaneous kidney-pancreas, liver-kidney, heart-kidney, heart-liver, heart-lung, lung-liver, and lung-kidney transplants. To date, no comprehensive review exists to address immunosuppressive strategies in simultaneous organ transplant populations. Our review summarizes the available literature and provides evidence-based recommendations regarding immunosuppression strategies in simultaneous organ transplant recipients.

Challenges of calcineurin inhibitor withdrawal following combined pancreas and kidney transplantation: Results of a prospective, randomized clinical trial

In a phase 2 multicenter open-label randomized trial sponsored by the National Institutes of Health, simultaneous pancreas-kidney (SPK) recipients were randomized to a calcineurin inhibitor (CNI)-based immunosuppressive regimen (tacrolimus) (n = 21), or an investigational arm using low-dose CNI plus costimulation blockade (belatacept) with intended CNI withdrawal (n = 22). Both arms included induction therapy with rabbit ATG, mycophenolate sodium, or mycophenolate mofetil and rapid withdrawal of steroids. Enrollment and CNI withdrawal were stopped after 43/60 planned subjects had been enrolled. At that time, the rate of biopsy-proven acute rejection (BPAR) of the pancreas was low in both groups until CNI was withdrawn, with four of the five pancreas rejections occurring during or after CNI withdrawal. The rate of BPAR of kidney allografts was low in both control (9.5%) and investigational (9.1%) arms. Pancreas graft survival at 52 weeks, defined by insulin independence, was 21 (100%) in the control group and 19 (86%) in the investigational arm. One subject in the investigational arm died with functioning pancreas and kidney grafts. Renal function at week 52 was similar in both arms. Costimulation blockade with belatacept did not provide sufficient immunosuppression to reliably prevent pancreas rejection in SPK transplants undergoing CNI withdrawal.

Sirolimus vs mycophenolate mofetil (MMF) in primary combined pancreas and kidney transplantation. Results of a long-term prospective randomized study

The study was intended to compare pancreas graft survival rates in two groups of pancreas and kidney transplant recipients prospectively randomized to treatment either with sirolimus or MMF. From 2002 to 2013, 238 type 1 diabetic recipients with end-stage kidney disease were randomized 1:1 to sirolimus or MMF treatment. Noncensored pancreas survival at 5 years was 76.4 and 71.6% for sirolimus and MMF groups, respectively (P > .05). Death-censored pancreas survival was better in the sirolimus group (P = .037). After removal of early graft losses pancreas survival did not differ between groups (MMF 83.1% vs sirolimus 91.6%, P = .11). Nonsignificantly more grafts were lost due to rejection in the MMF group (10 vs 5; P = .19). Cumulative patient 5-year survival was 96% in the MMF group and 91% in the sirolimus group (P > .05). Five-year cumulative noncensored kidney graft survival rates did not statistically differ (85.6% in the sirolimus group and 88.8% in MMF group). Recipients treated with MMF had significantly more episodes of gastrointestinal bleeding (7 vs 0, P = .007). More recipients in the sirolimus group required corrective surgery due to incisional hernias (21 vs 12, P = .019). ClinicalTrials No.: NCT03582878.

The survival advantage of pancreas after kidney transplant

Patient survival after pancreas after kidney transplant (PAK) has been reported to be inferior to patient survival after simultaneous pancreas-kidney transplant (SPK). The authors examine national data to further explore allograft (kidney and pancreas) and patient survival after PAK. Kaplan-Meier and Cox proportional hazard models were used to analyze Organ Procurement and Transplantation Network data from 1995 to 2010. The analysis compared PAK and SPK candidates and recipients. Kaplan-Meier analysis results showed that PAK after either a living or a deceased donor kidney transplant is associated with increased kidney graft survival compared with recipients with type 1 diabetes who received only a kidney. The best kidney allograft survival was for patients who received a living donor kidney followed by PAK. Receiving a living donor kidney was associated with increased pancreas allograft survival compared with receiving a deceased donor kidney. PAK transplant recipients who receive both organs have a survival advantage compared with uremic candidates who receive neither (SPK waitlist). Compared with uremic diabetic waitlist patients, SPK and PAK recipients showed similar overall patient survival. Successful PAK offers a survival advantage compared with receiving neither a kidney nor a pancreas transplant. These data also suggest that receiving a pancreas (after kidney) transplant may have a protective effect on the kidney allograft.

Steroid-free three-drug maintenance regimen for pancreas transplant alone: Comparison of induction with rabbit antithymocyte globulin +/- rituximab

Graft survival following pancreas transplant alone (PTA) is inferior to other pancreas transplants. Steroid elimination is appealing, but a two-drug maintenance strategy may be inadequate. Additionally, recipients tend to have diabetic nephropathy and do not tolerate nephrotoxic medications. A three-drug maintenance strategy permits immunosuppression through different mechanisms as well as an opportunity to use lower doses of the individual medications. Induction consisted of five doses of rabbit antithymocyte globulin (1 mg/kg/dose). As of October 2007, a single dose of rituximab (150 mg/m² ) was added. Maintenance consisted of tacrolimus, sirolimus and mycophenolate mofetil. From 2004 to 2017, 166 PTA were performed. Graft loss at 7 and 90 days were 4% and 5%, and 1-year patient and graft survival were 97% and 91%. Comparing induction without and with rituximab, there was no significant difference in 7- or 90-day graft loss, 1-year patient or graft survival, or in the rate of rejection or infection. Rabbit antithymocyte globulin induction and steroid withdrawal followed by a three-drug immunosuppression regimen is an excellent strategy for PTA recipients.

The Effect of Corticosteroid Withdrawal on Glucose Metabolism and Anti-GAD Antibodies in Simultaneous Pancreas-Kidney Transplant Patients

CONTEXT

Corticosteroid withdrawal may reduce insulin resistance; however, it could also influence pancreatic autoantibody profile in simultaneous pancreas-kidney (SPK) transplant patients.

OBJECTIVE

To evaluate the effect of corticosteroid withdrawal on glucose metabolism and anti-glutamic acid decarboxylase (GAD) antibody titers in SPK patients with type 1 diabetes after 12 months of follow-up.

DESIGN

In this retrospective study, fasting glucose and glycated hemoglobin (A1c) were compared before and after 3, 6, and 12 months of corticosteroid withdrawal in 80 SPK patients. In addition, weight, anti-GAD, and C-peptide levels were compared before and after withdrawal. Finally, fasting and postglucose, insulin, and C-peptide levels were compared before and after withdrawal in 25 patients undergoing oral glucose tolerance test (OGTT).

RESULTS

Fasting glucose levels did not change during corticosteroid discontinuation. After 12 months, A1c slightly increased from 4.6% (0.4%) to 4.8% (0.6%) (P < .01) and C-peptide decreased from 2.8 (1.1) ng/mL to 2.4 (1.3) ng/mL (P <. 01). In patients submitted to OGTT, glucose, insulin, and C-peptide levels did not change. There was no alteration in the proportion of anti-GAD positive tests (41% vs 45%). Anti-GAD titers remained stable or decreased in 70% of positive patients.

CONCLUSION

Corticosteroid withdrawal has no significant effect on glucose metabolism and on anti-GAD profile among SPK patients.

Allograft Pancreatectomy: Indications and Outcomes

This study evaluated the indications, surgical techniques, and outcomes of allograft pancreatectomy based on a single center experience. Between 2003 and 2013, 47 patients developed pancreas allograft failure, excluding mortality with a functioning pancreas allograft. Early graft loss (within 14 days) occurred in 16, and late graft loss in 31. All patients with early graft loss eventually required allograft pancreatectomy. Nineteen of 31 patients (61%) with late graft loss underwent allograft pancreatectomy. The main indication for early allograft pancreatectomy included vascular thrombosis with or without severe pancreatitis, whereas one recipient required urgent allograft pancreatectomy for gastrointestinal hemorrhage secondary to an arterioenteric fistula. In cases of late allograft pancreatectomy, graft failure with clinical symptoms such as abdominal discomfort, pain, and nausea were the main indications (13/19 [68%]), simultaneous retransplantation without clinical symptoms in 3 (16%), and vascular catastrophes including pseudoaneurysm and enteric arterial fistula in 3 (16%). Postoperative morbidity included one case each of pulmonary embolism leading to mortality, formation of pseudoaneurysm requiring placement of covered stent, and postoperative bleeding requiring relaparotomy eventually leading to femoro-femoral bypass surgery 2 years after allograftectomy. Allograft pancreatectomy can be performed safely, does not preclude subsequent retransplantation, and may be lifesaving in certain instances.

New directions for rabbit antithymocyte globulin (Thymoglobulin(®)) in solid organ transplants, stem cell transplants and autoimmunity

In the 30 years since the rabbit antithymocyte globulin (rATG) Thymoglobulin^® was first licensed, its use in solid organ transplantation and hematology has expanded progressively. Although the evidence base is incomplete, specific roles for rATG in organ transplant recipients using contemporary dosing strategies are now relatively well-identified. The addition of rATG induction to a standard triple or dual regimen reduces acute cellular rejection, and possibly humoral rejection. It is an appropriate first choice in patients with moderate or high immunological risk, and may be used in low-risk patients receiving a calcineurin inhibitor (CNI)-sparing regimen from time of transplant, or if early steroid withdrawal is planned. Kidney transplant patients at risk of delayed graft function may also benefit from the use of rATG to facilitate delayed CNI introduction. In hematopoietic stem cell transplantation, rATG has become an important component of conventional myeloablative conditioning regimens, following demonstration of reduced acute and chronic graft-versus-host disease. More recently, a role for rATG has also been established in reduced-intensity conditioning regimens. In autoimmunity, rATG contributes to the treatment of severe aplastic anemia, and has been incorporated in autograft projects for the management of conditions such as multiple sclerosis, Crohn’s disease, and systemic sclerosis. Finally, research is underway for the induction of tolerance exploiting the ability of rATG to induce immunosuppresive cells such as regulatory T-cells. Despite its long history, rATG remains a key component of the immunosuppressive armamentarium, and its complex immunological properties indicate that its use will expand to a wider range of disease conditions in the future.

Initial experience of dual maintenance immunosuppression with steroid withdrawal in vascular composite tissue allotransplantation

Current immunosuppression in VCA is largely based on the experience in solid organ transplantation. It remains unclear if steroids can be reduced safely in VCA recipients. We report on five VCA recipients who were weaned off maintenance steroids after a median of 2 months (mean: 4.8 months, range 2-12 months). Patients were kept subsequently on a low dose, dual maintenance consisting of tacrolimus and mycophenolate mofetil/mycophenloic acid with a mean follow-up of 43.6 months (median = 40 months, range 34-64 months). Early and late acute rejections responded well to temporarily augmented maintenance, topical immunosuppression, and/or steroid bolus treatment. One late steroid-resistant acute rejection required treatment with thymoglobulin. All patients have been gradually weaned off steroids subsequent to the treatment of acute rejections. Low levels of tacrolimus (<5 ng/mL) appeared as a risk for acute rejections. Although further experience and a cautious approach are warranted, dual-steroid free maintenance immunosuppression appears feasible in a series of five VCA recipients.

Immunosuppression for pancreas transplantation with an emphasis on antibody induction strategies: review and perspective

A review of recent literature was performed to identify trends and evaluate outcomes with respect to immunosuppression in pancreas transplantation (PTX). In the past decade, the majority of PTXs were performed with depleting antibody induction, particularly in the setting of either calcineurin inhibitor minimization, corticosteroid withdrawal or both. Maintenance immunosuppression consisted of predominantly tacrolimus (TAC)/mycophenolatemofetil, TAC/mycophenolic acid or TAC/sirolimus with or without corticosteroids. Depending on PTX category, donor and recipient risk factors, case mix and immunosuppressive regimen, the 1-year incidence of acute rejection has decreased to 5-20%. Current 1-year rates of immunological pancreas graft loss range between 1.8 and 6%. Depleting antibody induction and either TAC/mycophenolatemofetil or TAC/sirolimus maintenance therapy with early steroid withdrawal have become the mainstay of immunosuppression in PTX. However, the development of non-nephrotoxic, nondiabetogenic, and nongastrointestinal toxic regimens is highly desirable to improve quality of life in all solid organ transplant recipients.

Emerging trends in infections among renal transplant recipients

Outcomes following renal and simultaneous kidney-pancreas transplants have improved significantly due to better surgical techniques and improved modalities of antirejection therapy. However, infection remains a significant cause of morbidity and mortality. The use of new modalities of immunosuppression and routine use of antimicrobial prophylaxis has changed the pattern of infections post-transplantation. Cytomegalovirus remains a significant problem and BK virus has emerged as an important pathogen. New antimicrobial agents are now available to treat infection, however, antimicrobial resistance remains a concern.

Evidence for rapamycin toxicity in pancreatic β-cells and a review of the underlying molecular mechanisms

Rapamycin is used frequently in both transplantation and oncology. Although historically thought to have little diabetogenic effect, there is growing evidence of β-cell toxicity. This Review draws evidence for rapamycin toxicity from clinical studies of islet and renal transplantation, and of rapamycin as an anticancer agent, as well as from experimental studies. Together, these studies provide evidence that rapamycin has significant detrimental effects on β-cell function and survival and peripheral insulin resistance. The mechanism of action of rapamycin is via inhibition of mammalian target of rapamycin (mTOR). This Review describes the complex mTOR signaling pathways, which control vital cellular functions including mRNA translation, cell proliferation, cell growth, differentiation, angiogenesis, and apoptosis, and examines molecular mechanisms for rapamycin toxicity in β-cells. These mechanisms include reductions in β-cell size, mass, proliferation and insulin secretion alongside increases in apoptosis, autophagy, and peripheral insulin resistance. These data bring into question the use of rapamycin as an immunosuppressant in islet transplantation and as a second-line agent in other transplant recipients developing new-onset diabetes after transplantation with calcineurin inhibitors. It also highlights the importance of close monitoring of blood glucose levels in patients taking rapamycin as an anticancer treatment, particularly those with preexisting glucose intolerance.

Multicenter Australian trial of islet transplantation: improving accessibility and outcomes

Whilst initial rates of insulin independence following islet transplantation are encouraging, long-term function using the Edmonton Protocol remains a concern. The aim of this single-arm, multicenter study was to evaluate an immunosuppressive protocol of initial antithymocyte globulin (ATG), tacrolimus and mycophenolate mofetil (MMF) followed by switching to sirolimus and MMF. Islets were cultured for 24 h prior to transplantation. The primary end-point was an HbA1c of <7% and cessation of severe hypoglycemia. Seventeen recipients were followed for ≥ 12 months. Nine islet preparations were transported interstate for transplantation. Similar outcomes were achieved at all three centers. Fourteen of the 17 (82%) recipients achieved the primary end-point. Nine (53%) recipients achieved insulin independence for a median of 26 months (range 7-39 months) and 6 (35%) remain insulin independent. All recipients were C-peptide positive for at least 3 months. All subjects with unstimulated C-peptide >0.2 nmol/L had cessation of severe hypoglycemia. Nine of the 17 recipients tolerated switching from tacrolimus to sirolimus with similar graft outcomes. There was a small but significant reduction in renal function in the first 12 months. The combination of islet culture, ATG, tacrolimus and MMF is a viable alternative for islet transplantation.

Vascular catastrophes following pancreas transplantation: an evolution in strategy at a single center

INTRODUCTION

Complications of pancreas transplantation involving the arterial anastomosis are potentially life threatening. In this report, we review our experience with such vascular catastrophes.

METHODS

Pancreas transplants performed between January 2003 and December 2009 were reviewed. All cases of pseudoaneurysm (PA) or arterioenteric fistula (AEF) were included.

RESULTS

Of 346 pancreas transplants, 10 vascular catastrophes in nine recipients were identified. There were five PAs, one involving the pancreas allograft, one involving the donor iliac artery Y-graft stump following allograft pancreatectomy, two involving the kidney allograft, and one involving the bifurcation of the Y-graft. The latter was treated with coil embolization, but subsequently developed into an AEF. There were five AEFs including the recipient mentioned above. Four had a failed allograft and three had discontinued immunosuppression. The final case had a clamp injury to the proximal common iliac artery that fistulized to the donor duodenum. The management, course and outcome of all nine recipients are described in detail.

CONCLUSION

Vascular catastrophes such as PA and AEF are potentially life-threatening complications of pancreas transplantation. Immediate treatment at the time of bleeding is essential and covered stenting of the involved artery may provide immediate vascular control in these situations.

Pancreas transplantation after bariatric surgery

Obese transplant candidates are at increased risk for perioperative and postoperative complications. In many transplant programs, morbid obesity is considered to be an exclusion criterion for transplantation. The only potential option that would grant these patients access to transplant is weight loss. Non-operative weight loss strategies such as behavioral modifications, exercise, diet, or medication have only very limited success in achieving long-term weight loss. In contrast, bariatric surgery was shown to achieve not only more excessive weight loss, but more importantly, this weight loss can be sustained for longer periods of time. Therefore, bariatric surgery presents an attractive option for weight loss for morbidly obese transplant candidates. We report our experience with four patients who underwent bariatric surgery prior to successful pancreas transplantation. Even though gastric bypass and laparoscopic adjustable gastric band present as equivalent alternatives for weight reduction, we believe that in the population of morbidly obese diabetic patients who are possible candidates for pancreas transplantation, laparoscopic adjustable gastric band placement is the more suitable procedure.

Early reexploration for suspected thrombosis after pancreas transplantation

BACKGROUND

Graft thrombosis is the most common cause of early graft loss after pancreas transplantation. Early reexploration may permit salvage or timely removal of the thrombosed graft.

METHODS

This was a retrospective review of 345 pancreas transplants performed at a single center between January 2003 and December 2009. Early reexploration was defined as within 1 week of pancreas transplantation.

RESULTS

Of the 345 transplants, there were 35 early reexplorations. The graft was compromised in 20 cases (57%): 10 venous thromboses, 3 arterial thromboses, 2 combined arterial and venous thrombosis, 2 thromboses secondary to allograft pancreatitis, and 3 cases of positional ischemia without thrombosis. Of these allografts, three reperfused once repositioned and six were successfully thrombectomized for a graft salvage rate of 45%. One of the thrombectomized grafts remained perfused but never functioned and was removed at retransplantation. The 10 remaining compromised grafts that were deemed unsalvageable and required allograft pancreatectomy. Nine of these recipients were retransplanted (eight within 2 weeks) and one was not a retransplantation candidate.

CONCLUSIONS

Reexploration for suspected graft thrombosis after pancreas transplantation resulted in a negative laparotomy rate of 43%, but permitted graft salvage in 45% of compromised grafts.

Rabbit antithymocyte globulin (thymoglobulin): 25 years and new frontiers in solid organ transplantation and haematology

The more than 25 years of clinical experience with rabbit antithymocyte globulin (rATG), specifically Thymoglobulin, has transformed immunosuppression in solid organ transplantation and haematology. The utility of rATG has evolved from the treatment of allograft rejection and graft-versus-host disease to the prevention of various complications that limit the success of solid organ and stem cell transplantation. Today, rATG is being successfully incorporated into novel therapeutic regimens that seek to reduce overall toxicity and improve long-term outcomes. Clinical trials have demonstrated the efficacy and safety of rATG in recipients of various types of solid organ allografts, recipients of allogeneic stem cell transplants who are conditioned with both conventional and nonconventional regimens, and patients with aplastic anaemia. Over time, clinicians have learnt how to better balance the benefits and risks associated with rATG. Advances in the understanding of the multifaceted mechanism of action will guide research into new therapeutic areas and future applications.

Immunosuppression in simultaneous pancreas-kidney transplantation: progress to date

Simultaneous pancreas-kidney transplantation (SPKT) is the treatment of choice for patients with end-stage renal failure due to type 1 diabetes mellitus. With advances in surgical techniques and immunosuppression management, outcomes have improved, with current 1- and 10-year pancreas graft survival rates of 86% and 53%, respectively. Induction therapy with either alemtuzumab or rabbit antithymocyte globulin (rATG) in combination with a calcineurin inhibitor (CNI) and mycophenolate mofetil (MMF) or sirolimus appears to be safe and effective in the setting of rapid steroid withdrawal (RSW), with excellent graft survival and low rejection rates. There are no large randomized trials between alemtuzumab and rATG to determine whether one is better than the other. Anti-interleukin (IL)-2 receptor antibody induction and no induction in combination with a CNI, MMF or sirolimus, and prednisone have demonstrated excellent graft survival rates but are associated with a higher incidence of acute rejection. The efficacy of anti-IL-2 receptor antibodies or no induction in the setting of RSW is unproven. Both of the CNIs, ciclosporin and tacrolimus, are effective in preventing acute rejection in SPKT recipients; however, pancreas allograft survival may be better with tacrolimus. MMF is more effective than azathioprine in preventing acute rejection. Sirolimus appears to be effective in preventing acute rejection, but the combination of sirolimus with a CNI may accentuate the nephrotoxicity of the CNI. RSW with induction therapy is safe and effective in SPKT recipients, but longer follow-up data on outcomes are needed. Recent analysis of registry data shows that most transplant centres are using an induction agent followed by a combination of tacrolimus, MMF and corticosteroids in SPKT recipients.

The success of continued steroid avoidance after kidney transplantation in the US

There has been a significant increase in the use of steroid avoidance regimens as initial treatment for kidney transplant recipients. Early results of the effectiveness of this strategy has been mixed with certain prospective trials indicating increased acute rejection but population-based studies indicating similar or better graft survival as compared to steroid maintenance. We conducted a retrospective study of national registry data to evaluate risk factors for discontinuation of steroid avoidance protocols based on patient characteristics and concomitant immunosuppression. We evaluated 84 647 solitary kidney transplant recipients in the US with at least 6 months graft survival including 24 218 initially discharged without maintenance steroids. We utilized logistic models to assess risk factors for new initiation of steroids after initial steroid-avoidance and survival models to describe graft survival for patients after return to steroids. The most prominent risk factors for new initiation of steroids after deceased donor kidney transplantation included African-American race (AOR = 1.32, p < 0.01), retransplants (AOR = 1.81, p < 0.01), highly sensitized recipients (AOR = 1.29, p < 0.01), recipients with Medicaid (AOR = 1.85, p < 0.01), elevated HLA-MM (AOR = 1.26, p < 0.01) and older donor age (AOR = 1.19, p < 0.01). Concomitant medications were also significantly associated with the propensity to newly initiate steroids. Cumulatively the study suggests that both patient characteristics and concomitant medications are strongly associated with the success of steroid avoidance immunosuppressive regimens.

Development of BK nephropathy in recipients of simultaneous pancreas-kidney transplantation

BACKGROUND

BK nephropathy (BKVN) is a significant cause of graft dysfunction in kidney transplant recipients, but its course in simultaneous pancreas-kidney (SPK) recipients is less well studied. The presence of dual organs limits the ability to reduce maintenance immunosuppression, typically the first intervention in the management of BKVN.

METHODS

A single center, retrospective review was conducted of 205 SPK transplants performed from January 1, 2000 to April 30, 2006.

RESULTS

The 5-year actuarial cumulative rate of BKVN was 5.6%. Diagnosis occurred at a median of 20 months after transplant; mean serum creatinine was 2.6, and geometric mean BK serum viral load was 709,274 copies/mL at diagnosis. There was no statistical difference in the cumulative rate according to the use of induction therapy: rabbit antilymphocyte globulin (5-year rate 6.8%, 4/59), alemtuzumab (5-year rate 5.1%, 5/146). Treatment consisted of immunosuppression reduction and half received cidofovir. Eight of nine kidney allografts eventually failed, but all patients retained pancreatic allograft function.

CONCLUSIONS

BKVN occurs in 5.6% of SPK recipients. There is no difference in the cumulative rate of BKVN between patients who received alemtuzumab or rabbit antilymphocyte globulin.

Immediate retransplantation for pancreas allograft thrombosis

Early pancreas allograft failure most commonly results from thrombosis and requires immediate allograft pancreatectomy. Optimal timing for retransplantation remains undefined. Immediate retransplantation facilitates reuse of the same anatomic site before extensive adhesions have formed. Some studies suggest that early retransplantation is associated with a higher incidence of graft loss. This study is a retrospective review of immediate pancreas retransplants performed at a single center. All cases of pancreas allograft loss within 2 weeks were examined. Of 228 pancreas transplants, 12 grafts were lost within 2 weeks of surgery. Eleven of these underwent allograft pancreatectomy for thrombosis. One suffered anoxic brain injury and was not a retransplantation candidate, one was retransplanted at 3.5 months and nine patients underwent retransplantation 1-16 days following the original transplant. Of the nine early retransplants, one pancreas was lost to heparin-induced thrombocytopenia, one recipient died with function at 2.9 years and the other grafts continue to function at 76-1137 days (mean 572 days). One-year graft survival for early retransplantation was 89% compared to 91% for all pancreas transplants at our center. Immediate retransplantation following pancreatic graft thrombosis restores durable allograft function with outcomes comparable to first-time pancreas transplantation.

Minimization of steroids in liver transplantation

Because of the markedly improved short-term results of liver transplantation (LT) and persistently high number of long-term complications, the attention of transplant physicians should be focused on minimizing immunosuppressive therapy as much as possible. Steroid-based immunosuppression is responsible for a substantial post-LT morbidity and mortality, hence, minimization of its use is of utmost importance to improve the quality of life of the successfully transplanted liver recipient. This literature review shows that LT can be performed safely with steroid-minimal immunosuppression without compromising graft and patient survival. The tendency in clinical practice is to move more and more from steroid withdrawal to steroid avoidance protocols.

Minimization of steroids in kidney transplantation

The goal of steroid minimization trials has been to minimize or eliminate steroid-related side-effects while simultaneously not increasing the rate of acute rejection (AR) and chronic graft loss. Early trials of late steroid withdrawal (> or =3 months post-transplant) were associated with significantly increased AR rates and late graft loss. More recent trials of rapid discontinuation of prednisone (RDP) (< or =7 days post-transplant) have been associated with little or no increase in AR rates and no difference in graft survival (versus maintenance prednisone). Of note, induction therapy appears to be important for success; however, it is not clear if any single maintenance protocol is superior. Intermediate-term follow-up (5-7 years) is now available for some randomized and nonrandomized trials; graft survival and renal function remain excellent. Most of these trials have been done in low immunologic risk recipients, but there are reports of success of RDP in children, black recipients, sensitized recipients, recipients with potentially recurring disease, and kidney-pancreas recipients. Of critical importance, steroid-related side-effects have been minimized. Steroid minimization protocols can clearly be recommended for low-risk patients; additional trials are necessary for those at higher risk. Additional research is also necessary on integrating calcineurin inhibitor minimization with steroid minimization.

Steroid elimination-who, when, how?

Steroids have numerous side effects, many occurring early posttransplantation with relatively low prednisone doses. Consequently, investigators have attempted steroid minimization or withdrawal. The first attempts at steroid minimization used early low-dose steroids and were associated with an increased rate of acute rejection episodes, late graft dysfunction, and graft loss. Subsequent studies, with cyclosporine-based immunosuppression, attempted steroid withdrawal late posttransplantation (>3 months) in highly selected, clinically well, and immunologically low-risk recipients. Again, steroid withdrawal was associated with an increased risk of acute rejection episodes and these episodes were associated with graft dysfunction and increased graft loss. The development of new powerful immunosuppressive agents has led to renewed attempts at late prednisone withdrawal. These also have been associated with increased late rejection risk. A more exciting innovation has been the attempts at rapid discontinuation ( Collapse

Key Words Collapse

MESH Headings

• Adrenal Cortex Hormones/adverse effects
• Antilymphocyte Serum/therapeutic use
• Clinical Trials as Topic
• Drug Administration Schedule
• Drug Therapy, Combination
• Graft Rejection/epidemiology
• Graft Rejection/prevention & control
• Graft Survival/drug effects
• Graft Survival/physiology
• Humans
• Immunosuppressive Agents/therapeutic use
• Kidney Transplantation/immunology
• Prednisone/adverse effects

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Grants

• P01 DK013083 NIDDK NIH HHS
• DK 13083 NIDDK NIH HHS

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Affiliation(s)

A J Matas Department of Surgery, University of Minnesota, Minneapolis, Minnesota 55455, USA.

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Prevention and management of hyperglycemia after pancreas transplantation

PURPOSE OF REVIEW

Pancreas transplantation is considered the optimal therapy for patients with insulin-dependent diabetes. Successful pancreas transplantation achieves euglycemia and allows freedom from insulin therapy. Long-term allograft success may be limited by the development of impaired glucose metabolism. The objectives of the present review are to summarize the possible reasons for endocrine pancreatic dysfunction and to focus on its prevention and management and emphasize the role of immunosuppression.

RECENT FINDINGS

The diabetogenic effects of current immunosuppressive agents have been well established. Regimens without corticosteroids and calcineurin-inhibitor minimization or avoidance have been promoted. Recent studies have revisited the pathogenesis of type I and type II diabetes and demonstrated common pathways, including apoptosis induction, for the exhaustion and destruction of the pancreatic islets.

SUMMARY

The immunosuppressive regimens in pancreatic transplantation should be designed and appropriately modified according to the graft immunological and metabolic conditions. New molecules that are able to preserve islet function and maintain optimal insulin secretion should be considered for pancreas transplant recipients.

Minimization and withdrawal of steroids in pancreas and islet transplantation

For reducing the corticosteroid (CS)-related side-effects, especially cardiovascular events, CS-sparing protocols have become increasingly common in pancreas transplantation (PT). Lympho-depleting induction antibodies, such as rabbit anti-thymocyte globulin (rATG) or alemtuzumab, have been widely used in successful trials. The results of various CS-sparing protocols combining calcineurin inhibitors (CNI) and mycophenolate or sirolimus, have been mixed for rejection and survival rates. Most of the studies were uncontrolled trials of low-risk patients, therefore the grade of evidence is limited. Large-scale prospective studies with long-term follow up are necessary to assess risks and benefits of CS-sparing regimens in PT before recommending such strategies as standard practice. Islet allo-transplantation for patients with brittle type 1 diabetes mellitus, less invasive and safer procedure than PT, has been attempted since late 1980s, but diabetogenic immunosuppressants at maintenance, mainly CS and high-dose CNI, prevented satisfactory results (10% insulin-independence at 1-year post-transplant). Since 2000, CS-free and CNI-reducing protocols, including more potent induction [daclizumab, OKT3gamma1(ala-ala) anti-CD3 antibody, rATG] and maintenance (sirolimus, mycophenolate) agents, have significantly improved short-term outcomes whereas long-term are still inadequate (from 80% to 20% insulin-independence from 1- to 5-year post-transplant). Main limitations are allo- and autoimmunity, immunosuppression-related islet and systemic toxicity and transplant site unsuitability, which tolerogenic protocols and biotechnological solutions may solve.

Selective corticosteroid and calcineurin-inhibitor withdrawal after pancreas-kidney transplantation utilizing thymoglobulin induction and sirolimus maintenance therapy

Of 25 simultaneous pancreas-kidney transplant (SPK) recipients treated with thymoglobulin induction, sirolimus and reduced-dose cyclosporine (CsA), 18 low-immune responders (non-African-Americans, PRA < 30%) were withdrawn from prednisone on post-transplant day 5, whereas seven high-immune responders continued on prednisone. Most high- and low-immune responder recipients were converted from CsA to mycophenolic acid (MPA) at six months post-transplantation. At a mean follow-up of 28 +/- 10 months, two pancreas grafts were lost to pancreatitis. There were no patient or kidney graft losses, but one acute rejection episode. At 28 +/- 11 months, all 18 low-responder recipients remain steroid-free. Twenty recipients (14 low and six high-immune responders) were converted from CsA to MPA. During conversion, immune response was monitored by Flow-PRA and T-cell stimulation (Cylex) assays. Nineteen of 20 recipients displayed a post-conversion PRA of 0%, whereas one highly sensitized patient expressed a post-conversion PRA of 67%. Fifty-eight percent of individual T-cell stimulation scores were in the hypo-responsive range. Twelve of 18 low-immune responders are both steroid and CsA-free at a mean follow-up of 17 +/- 13 months, whereas five of seven high-immune responders remain CsA-free at a mean follow-up of 11 +/- 10 months. These data suggest that thymoglobulin induction with combined sirolimus and CsA maintenance therapy permits immunosuppression minimization in selected SPK recipients.

Organ preservation with histidine-tryptophan ketogluatarate solution in clinical pancreas transplantation: an update of the indiana university experience

In May 2003, University of Wisconsin (UW) solution was replaced with Histidine-Tryptophan Ketoglutarate (HTK) solution as the preservation fluid for abdominal organ procurements in our center. Herein we have reported our updated results with HTK in pancreas transplantation. Between May 2003 and October 2006, 152 pancreas transplantations were performed in which 146 used HTK. The procedures were as follows: simultaneous kidney pancreas transplantation (n = 85; 55%), pancreas after kidney transplantation (n = 41; 30%), and solitary pancreas transplantation (n = 20; 15%). Donor and recipient data were collected with primary outcomes as primary nonfunction (PNF), and 30-day and 1-year graft and patient survival. Patient demographics are as follows: age (36 +/- 12 years), gender (males, 89: females, 57), race (white, 135; African American, 11). Mean flush volume was 3.8 +/- 1 L. The mean cold ischemia time was 8 +/- 3 hours. Mean warm ischemia time was 48 +/- 23 minutes. There were no cases of PNF in this cohort. Thirty-day and 1-year patient survival rates were 99% and 95%, respectively. The 30-day and 1-year graft survivals rates were 95% and 93%, respectively. There were 10 grafts lost with 7 vascular complications (6 venous and 1 arterial thrombosis). There were 2 cases of chronic rejection and 1 graft lost to noncompliance. These statistics compare favorably with International Pancreas Transplant Registry reported 1-year survival for pancreas allografts. All other patients were insulin independent by discharge. Serum fasting blood glucose and serial amylase remained comparable at all intervals posttransplantation to those of a historical UW cohort. Within this range of cold ischemia times, HTK appears to provide effective pancreas preservation.

Pretransplant donor-specific and non-specific immune parameters associated with early acute rejection

BACKGROUND

New immunosuppression protocols have resulted in decreased rates of biopsy-proven acute rejection; however, it is unclear whether recipients without biopsy-proven acute rejection are still at risk for immune complication and chronic allograft dysfunction. The aim of our studies was to determine whether pretransplant immune parameters were associated with posttransplant early acute rejection, unstable creatinine courses, and poor graft outcome.

METHODS

Immune parameters, including human leukocyte antigen (HLA) mismatch, HLA-specific antibodies, global CD4+ cellular response as measured by intracellular adenosine triphosphate (iATP) synthesis, and IFN-gamma precursor frequencies to donor or third-party cells as measured by ELISPOT were determined for a total of 126 kidney recipients treated with a protocol, including rapid discontinuation of prednisone.

RESULTS

The donor specific pretransplant parameters of HLA class I mismatches (P=0.04) and total HLA mismatches (P=0.04) with the donor as well as the pretransplant HLA-donor specific antibodies (P=0.002) were associated with biopsy-proven acute rejection. Higher pretransplant iATP levels, a donor nonspecific parameter, were found associated with biopsy proven acute rejection (P=0.04). Pretransplant iATP levels were significantly greater for recipients with early unstable creatinine levels (P=0.01). Recipients with a pretransplant iATP value greater than 375 ng/ml were 3.67 times more likely to experience acute rejection (P=0.03).

CONCLUSIONS

Pretransplant assessment of donor specific and nonspecific immune parameters may identify recipients who can benefit from closer clinical and immunological surveillance to allow for tailored immunsuppression and selective intervention aimed at optimizing both short and long-term graft outcome.

Minimizing immunosuppression, an alternative approach to reducing side effects: objectives and interim result

Exceptionally low acute rejection rates and excellent graft survival can be achieved with cyclosporine and tacrolimus (CNI)-based immunosuppressive protocols that incorporate antiproliferative immunosuppressants and corticosteroids. However, despite short-term success, long-term attrition of graft function and side effects of immunosuppressive agents continue to be significant problems, leaving clinicians looking for possible interventions. CNI nephrotoxicity is but one of numerous factors that may contribute to long-term damage in transplant kidneys. Metabolic, cosmetic, and neuropsychiatric complications of steroids affect quality of life after transplantation. Newer immunosuppressive agents such as mycophenolate mofetil and sirolimus (Rapa) have raised the possibility of withdrawing or avoiding CNIs or steroids altogether. In this report we review studies that address either CNI or steroid minimization strategies and discuss their risks versus benefits. Given the accumulated experience to date, in our opinion the use of CNIs and steroids as part of immunosuppressive regimens remains the proven standard of care for renal transplant patients. The long-term safety and efficacy of CNI and steroid minimization strategies needs to be further validated in controlled clinical trials with adequate long-term follow-up.

Steroid-free maintenance immunosuppression with rapamune and low-dose neoral in pancreas transplant recipients

BACKGROUND

Steroid-free immunosuppression is an attractive option because it avoids the many side effects of chronic corticosteroid use. It is especially attractive in pancreas recipients because it avoids the diabetogenic effects of steroids.

METHODS

We evaluated the outcome of a steroid-free maintenance immunosuppressive protocol in pancreas transplant recipients. Between August 2003 and May 2006, a total of 97 pancreas transplant recipients received steroid-free maintenance immunosuppression, consisting of induction with thymoglobulin and prednisone for the first 5 days. Patients were maintained on sirolimus adjusted to a target rapamycin trough level and reduced-dose cyclosporine adjusted to target C2 levels. All pancreas transplants (n=124) performed in the previous 3 years and maintained on a steroid-based immunosuppressive protocol with cyclosporine and mycophenolate mofetil were used for comparison.

RESULTS

One-year patient and death censored pancreas graft survival were 93.8% and 94.8% for the steroid free group versus 95.2% and 87.9% for the comparator group, respectively. The incidence of acute rejection was 9.3% in the steroid-free group versus 28.3% in the comparator group (P<0.01). No pancreas loss in the steroid-free group was caused by acute rejection, whereas seven (5.6%) patients in the comparator group lost their pancreases because of acute rejection (P<0.05). At 1 year after transplant, the mean serum glucose and creatinine levels were not different between the two groups.

CONCLUSION

We conclude that excellent graft survival with a significantly lower incidence of acute rejection can be achieved using a steroid-free maintenance immunosuppressive protocol consisting of sirolimus and cyclosporine.