Influence of pancreas transplantation alone on native renal function

Kidney disease in non-kidney solid organ transplantation

Kidney disease after non-kidney solid organ transplantation (NKSOT) is a common post-transplant complication associated with deleterious outcomes. Kidney disease, both acute kidney injury and chronic kidney disease (CKD) alike, emanates from multifactorial, summative pre-, peri- and post-transplant events. Several factors leading to kidney disease are shared amongst solid organ transplantation in addition to distinct mechanisms unique to individual transplant types. The aim of this review is to summarize the current literature describing kidney disease in NKSOT. We conducted a narrative review of pertinent studies on the subject, limiting our search to full text studies in the English language. Kidney disease after NKSOT is prevalent, particularly in intestinal and lung transplantation. Management strategies in the peri-operative and post-transplant periods including proteinuria management, calcineurin-inhibitor minimization/ sparing approaches, and nephrology referral can counteract CKD progression and/or aid in subsequent kidney after solid organ transplantation. Kidney disease after NKSOT is an important consideration in organ allocation practices, ethics of transplantation. Kidney disease after SOT is an incipient condition demanding further inquiry. While some truths have been revealed about this chronic disease, as we have aimed to describe in this review, continued multidisciplinary efforts are needed more than ever to combat this threat to patient and allograft survival.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Long-term effects of pancreas transplant alone on nephropathy in type 1 diabetic patients with optimal renal function

Background

Limited data are available regarding optimal selection criteria for pancreas transplant alone (PTA) to minimize aggravation of diabetic nephropathy.

Methods

A total of 87 type 1 diabetic patients were evaluated before and after PTA at a single center from January, 1999 to December, 2015, together with 87 matched non-transplanted type 1 diabetic subjects who were candidates for PTA to compare deterioration of native kidney function. A total of 163 patients (79 in the transplanted group and 84 in the nontransplanted group) were finally enrolled after excluding nine patients with estimated glomerular filtration rate less than 60 mL/min/1.73 m² and two patients with moderate proteinuria (≥ 1.5 g/day).

Results

A total of seven recipients (8.9%) had end-stage renal disease post-transplant whereas only one patient (1.2%) developed end-stage renal disease in the nontransplanted group during their follow-up period (median 12.0, range 6–96 months) (p = 0.03). Furthermore, a composite of severe renal dysfunction and end-stage renal disease (31.6% vs 2.4%) was significantly higher in the transplanted group (p < 0.001). Multivariate Cox regression analysis revealed that a higher level of tacrolimus at six months post-transplant (HR = 1.648, CI = 1.140–2.385, p = 0.008) was the only significant factor associated with end-stage renal disease.

Conclusions

There is a considerable risk for deterioration of renal function in PTA recipients post-transplant compared with non-transplant diabetic patients. With rather strict selection criteria such as preoperative proteinuria and estimated glomerular filtration rate, PTA should be considered in diabetic patients to minimize post-transplant aggravation of diabetic nephropathy.

Outcomes of Recipients With Pancreas Transplant Alone Who Develop End-Stage Renal Disease

Recipients of pancreas transplant alone (PTA) may be at increased risk for developing end-stage renal disease (ESRD). The survival experience of PTA recipients developing ESRD has not been described. Furthermore, the relative survival of these patients as compared to diabetics on chronic dialysis is unknown. We studied all adult PTA recipients from January 1, 1990 to September 1, 2008 using the Scientific Registry of Transplant Recipients. Each PTA recipient developing ESRD was matched to 10 diabetics on chronic dialysis from the United States Renal Data System. Cox proportional hazards models were fitted to determine the relation between ESRD and mortality among PTA recipients, and the relation between PTA and mortality among diabetics on chronic dialysis. There were 1597 PTA recipients in the study, of which 207 developed ESRD. Those with ESRD had a threefold increase in mortality versus those without (adjusted hazard ratio 3.28 [95% confidence interval: 2.27, 4.76]). There was no significant difference in the risk of death among PTA recipients with ESRD versus diabetics on dialysis. PTA recipients developing ESRD are three times more likely to die than PTA recipients without ESRD; however, the risk of death in these patients was similar to diabetics on chronic dialysis without PTA.

Pancreas transplant alone: a procedure coming of age

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

Follow-up of secondary diabetic complications after pancreas transplantation

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Curing diabetes with transplantation?

Type 1 diabetes affects >1 million people in the United States, where it accounts for up to 10% of all diabetes cases. Glycemic control via the use of exogenous insulin injections in diabetic patients is incomplete, resulting in multiple long-term complications such as retinopathy, neuropathy, vasculopathy, and nephropathy. The goal of beta-cell replacement by whole-pancreas or islet transplantation is to achieve long-term insulin independence, and the proposed benefits are improved quality of life, prevention of recurrent diabetic nephropathy, stabilization or improvement in secondary complications, and improved mortality. No other regimen of insulin delivery can achieve this level of physiologic regulation.

Renal function in type 1 diabetics one year after successful pancreas transplantation

The effect of pancreas transplantation on renal function remains a matter of debate. The purpose of this retrospective, single-unit study is a preliminary analysis of renal function one yr after pancreas transplant (pancreas alone [PTA] or pancreas after kidney [PAK]). Fifty-nine patients were included. Serum creatinine and estimated glomerular filtration rate (eGFR) levels were compared three, six, and 12 months post-transplantation for the whole sample and separately for PTA and PAK and high (>45 mL/min/1.73 m(2)) and low (≤45 mL/min/1.73 m(2)) pre-transplant eGFR subgroups. Overall, eGFR did not change significantly (p = 0.228) at the end of the first year post-transplant, with patients of low initial eGFR presenting a more prominent trend toward stable or improved levels. In the PAK subgroup, eGFR was significantly improved (p = 0.035). High eGFR subgroup demonstrated no significant deterioration in renal function, while patients with low initial eGFR had significantly higher levels 3 (p = 0.012) and six months (p = 0.009) post-transplant. Our study shows that renal function did not deteriorate significantly one yr after pancreas transplant (PTA or PAK), even in patients with substantial pre-existing renal dysfunction. Evaluation at a wider scale and identification of risk factors for potential deterioration are challenges for future research.

Risk analysis for deterioration of renal function after pancreas alone transplant

The risk of progression to renal replacement after pancreas transplant alone (PTA) is a concern in patients with pre-transplant estimated glomerular filtration rate (eGFR) < 70 mL/min/1.73 m(2). This is a retrospective, single-center risk analysis of potential factors affecting renal function after PTA. Twenty-four patients, transplanted over a three-yr period, with functioning pancreatic grafts at the study's end point were included. High tacrolimus levels (> 12 mg/dL) at six months post-transplant was the only independent risk factor identifying a substantial decline in native renal function by Cox regression analysis (HR = 14.300, CI = 1.271-160.907, p = 0.031). The presence of severe pre-transplant proteinuria (urine Pr/Cr ≥ 100 mg/mmol) marginally failed to reach significance (p = 0.056). Low eGFR levels alone (≤ 45 and ≤ 40 mL/min/1.73 m(2)) at the time of transplant did not correlate with substantial decline in renal function. Our data suggest that PTA is a justifiable therapy for patients with hypoglycemia unawareness or other life-threatening diabetic complications, even in those with borderline renal function, provided that they do not suffer from severe proteinuria and appropriate monitoring and tailoring of immunosuppression is ensured.

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

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

Long-term benefits of pancreas transplantation

PURPOSE OF REVIEW

Pancreas transplantation has emerged as an effective treatment for patients with diabetes mellitus, especially those with established end-stage renal disease. Surgical and immunosuppressive advances have significantly improved allograft survival. With more recipients enjoying normoglycemia for longer periods of time, the opportunity to study more closely the effects of pancreas transplantation has arisen. This review will focus on these long-term benefits.

RECENT FINDINGS

The field of pancreas transplantation has been limited by a lack of randomized, controlled trials and relatively poor graft survival rates historically, however we can still glean many important points from the existing literature. The procedure reduces mortality compared with diabetic kidney transplant recipients and waitlisted patients. Improvements in diabetic nephropathy and retinopathy have also been demonstrated. Pancreas transplantation can improve cardiovascular risk profiles, improve cardiac function and decrease cardiovascular events. Lastly, improvements in diabetic neuropathy and quality of life can result from pancreas transplantation.

SUMMARY

Pancreas transplantation remains the most effective method to establish durable normoglycemia for patients with diabetes mellitus. Well designed clinical studies to assess outcomes and adverse events will be of paramount importance in providing optimal care to patients with diabetes mellitus.

Transplantation for the treatment of type 1 diabetes

Transplantation of pancreatic tissue, as either the intact whole pancreas or isolated pancreatic islets has become a clinical option to be considered in the treatment of patients with type 1 insulin-dependant diabetes mellitus. A successful whole pancreas or islet transplant offers the advantages of attaining normal or near normal blood glucose control and normal hemoglobin A1c levels without the risks of severe hypoglycemia associate with intensive insulin therapy. Both forms of transplants are also effective at eliminating the occurrence of significant hypoglycemic events (even with only partial islet function evident). Whereas whole pancreas transplantation has also been shown to be very effective at maintaining a euglycemic state over a sustained period of time, thus providing an opportunity for a recipient to benefit from improvement of their blood glucose control, it is associated with a significant risk of surgical and post-operative complications. Islet transplantation is attractive as a less invasive alternative to whole pancreas transplant and offers the future promise of immunosuppression-free transplantation through pre-transplant culture. Islet transplantation however, may not always achieve the sustained level of tight glucose control necessary for reducing the risk of secondary diabetic complications and exposes the patient to the adverse effects of immunosuppression. Although recent advances have led to an increased rate of obtaining insulin-independence following islet transplantation, further developments are needed to improve the long-term viability and function of the graft to maintain improved glucose control over time.

Transplantation for the treatment of type 1 diabetes

Transplantation of pancreatic tissue, as either the intact whole pancreas or isolated pancreatic islets has become a clinical option to be considered in the treatment of patients with type 1 insulin-dependant diabetes mellitus. A successful whole pancreas or islet transplant offers the advantages of attaining normal or near normal blood glucose control and normal hemoglobin A1c levels without the risks of severe hypoglycemia associate with intensive insulin therapy. Both forms of transplants are also effective at eliminating the occurrence of significant hypoglycemic events (even with only partial islet function evident). Whereas whole pancreas transplantation has also been shown to be very effective at maintaining a euglycemic state over a sustained period of time, thus providing an opportunity for a recipient to benefit from improvement of their blood glucose control, it is associated with a significant risk of surgical and post-operative complications. Islet transplantation is attractive as a less invasive alternative to whole pancreas transplant and offers the future promise of immunosuppression-free transplantation through pre-transplant culture. Islet transplantation however, may not always achieve the sustained level of tight glucose control necessary for reducing the risk of secondary diabetic complications and exposes the patient to the adverse effects of immunosuppression. Although recent advances have led to an increased rate of obtaining insulin-independence following islet transplantation, further developments are needed to improve the long-term viability and function of the graft to maintain improved glucose control over time.