Prediabetes in Patients Receiving Tacrolimus in the First Year After Kidney Transplantation: A Prospective and Multicenter Study

Post-transplant diabetes mellitus: Findings in nutritional status and body composition

INTRODUCTION

Weight gain and changes in body composition are associated with the onset of diabetes after kidney transplantation, and detailing these changes can help prevent this situation. The study aimed to assess the prevalence of diabetes mellitus after kidney transplantation and changes in the nutritional status and body composition in patients with diabetes one year from surgery.

MATERIALS AND METHODS

This survey was a single-center, prospective cohort study. Twenty-nine patients over 18 years old who underwent isolated kidney transplantation, without diabetes, were included and followed up for one year. At hospital discharge after transplantation and one year later, anthropometric (weight, height and abdominal circumference), body composition (electrical bioimpedance), routine biochemical and dietary intake assessments were performed.

RESULTS

Most of the patients were male (75%), and the mean age was 48.0±11.8 years old. In the first-year post-surgery 27.6% of patients had DM and the diagnosis was made, on average, 4 months after transplantation. The group with diabetes had, from the beginning to the end of the study, greater weight and body fat, especially abdominal fat. The non-diabetic group, after one year, showed an increase in phase angle, body weight and body masses, more pronounced of fat-free mass, when compared with fat mass gain.

CONCLUSIONS

Both groups showed weight gain, but in the non-diabetic group these changes can be interpreted as an improvement in the nutritional profile. Metabolic abnormalities associated with immunosuppression and eating habits, combination that maintains increased the risk for diabetes for long time, keeping this group with priority in nutritional care.

Exercise and Prediabetes After Renal Transplantation (EXPRED-I): A Prospective Study

BACKGROUND

Post-transplant diabetes mellitus (PTDM) beyond 12 months (late PTDM) is a severe complication after renal transplantation. Late PTDM develops mostly in subjects with prediabetes. Although exercise may have a potential role in preventing late PTDM, there are no previous data on the effect of exercise in patients with prediabetes.

MATERIAL AND METHODS

The design was a 12-month exploratory study to test the capacity of exercise in reverting prediabetes in order to prevent late-PTDM. The outcome was the reversibility of prediabetes, assessed every 3 months with oral glucose tolerance tests (OGTT). The protocol included an incremental plan of aerobic and/or strength training as well as an active plan for promoting adherence (telephone calls, digital technology, and visits). A priori, a sample size cannot be calculated which makes this an exploratory analysis. Based on previous studies, the spontaneous reversibility of prediabetes was 30% and the reversibility induced by exercise will account for another 30%, a total reversibility of 60% (p value < 0.05, assuming a potency of 85%). Ad interim analysis was performed during follow-up to test the certainty of this sample calculation. Patients beyond 12 months after renal transplantation with prediabetes were included.

RESULTS

The study was interrupted early due to efficacy after the evaluation of the follow-up of 27 patients. At the end of follow-up, 16 (60%) patients reverted to normal glucose levels at fasting (from 102.13 mg/dL ± 11 to 86.75 ± 6.9, p = 0.006) and at 120 min after the OGTTs (154.44 mg/dL ± 30 to 113.0 ± 13.1, p = 0.002) and 11 patients had persistent prediabetes (40%). Also, insulin sensitivity improved with the reversibility of prediabetes, compared to those with persistent prediabetes: 0.09 [0.08-0.11] versus 0.04 [0.01-0.07], p = 0.001 (Stumvoll index). Most needed at least one increment in the prescription of exercise and compliance. Finally, measures aimed at the improvement of compliance were successful in 22 (80%) patients.

CONCLUSION

Exercise training was effective to improve glucose metabolism in renal transplant patients with prediabetes. Exercise prescription must be conducted considering both the clinical characteristics of the patients and pre-defined strategy to promote adherence. The trial registration number of the study was NCT04489043.

Pretransplant evaluation and the risk of glucose metabolic alterations after renal transplantation: a prospective study

BACKGROUND

Post-transplant prediabetes (PreDM) and diabetes (PTDM) are common and have an impact on cardiovascular events. We sought to investigate the pathogenesis and best approach for prediction.

METHODS

We prospectively studied 115 waitlisted patients from a single center without manifest diabetes. An oral glucose tolerance test (OGTT) was performed yearly until transplantation and 12 months later. Insulin secretion, insulin sensitivity (IS) and disposition index (DI) were derived from the OGTT.

RESULTS

PreDM and PTDM were observed in 27% and 28.6% of patients, respectively. Pretransplant age, body mass index (BMI), 120 min glucose, IS, DI, and prediabetes or undiagnosed diabetes were significantly associated with these alterations. In multivariate analysis, pretransplant age [odds ratio (OR) 1.5; 95% confidence interval (CI) 1.04-2.1], BMI (OR 1.16; 95% CI 1.04-1.3) and cumulative steroids (OR 1.5; 95% CI 1.02-2.2) were predictors of PreDM or PTDM. Receiver operating characteristic curve analysis showed that pretransplant BMI and 120 min glucose had the highest area under the curve (0.72; 95% CI 0.62-0.8; and 0.69; 95% CI 0.59-0.79, respectively). The highest discrimination cut-off for BMI (≥28.5 kg/m2) and 120 min glucose (≥123.5 mg/dL) yielded a similar number needed to diagnose (2.5).

CONCLUSIONS

PreDM or PTDM develops in waitlisted patients with an ineffective insulin secretion and BMI shows a similar diagnostic capacity to OGTT. Pretransplant interventions may reduce post-transplant glucose alterations.

Sitagliptin Versus Placebo to Reduce the Incidence and Severity of Posttransplant Diabetes Mellitus After Kidney Transplantation-A Single-center, Randomized, Double-blind Controlled Trial

BACKGROUND

Postkidney transplant diabetes mellitus (PTDM) affects cardiovascular, allograft, and recipient health. We tested whether early intervention with sitagliptin for hyperglycemia (blood glucose >200 mg/dL) within the first week of transplant and discontinued at 3 mo could prevent development of PTDM in patients without preexisting diabetes.

METHODS

The primary efficacy objective was to improve 2-h oral glucose tolerance test (OGTT) by > 20 mg/dL at 3 mo posttransplant. The secondary efficacy objective was to prevent new onset PTDM, defined as a normal OGTT at 3 mo.

RESULTS

Sixty-one patients consented, and 50 patients were analyzed. The 3-mo 2-h OGTT (end of treatment) was 141.00 ± 62.44 mg/dL in the sitagliptin arm and 165.22 ± 72.03 mg/dL ( P  = 0.218) in the placebo arm. The 6-mo 2-h OGTT (end of follow-up) was 174.38 ± 77.93 mg/dL in the sitagliptin arm and 171.86 ± 83.69 ng/dL ( P  = 0.918) in the placebo arm. Mean intrapatient difference between 3- and 6-mo 2-h OGTT in the 3-mo period off study drug was 27.56  +  52.74 mg/dL in the sitagliptin arm and -0.14  +  45.80 mg/dL in the placebo arm ( P  = 0.0692). At 3 mo, 61.54% of sitagliptin and 43.48% of placebo patients had a normal 2-h OGTT ( P  = 0.2062), with the absolute risk reduction 18.06%. There were no differences in HbA1c at 3 or 6 mo between sitagliptin and placebo groups. Participants tolerated sitagliptin well.

CONCLUSION

Although this study did not show a significant difference between groups, it can inform future studies in the use of sitagliptin in the very early posttransplant period.

Diabetes mellitus in dialysis and renal transplantation

Diabetes mellitus is the commonest cause of end-stage kidney failure worldwide and is a proven and significant risk factor for the development of cardiovascular disease. Renal impairment has a significant impact on the physiology of glucose homeostasis as it reduces tissue sensitivity to insulin and reduces insulin clearance. Renal replacement therapy itself affects glucose control: peritoneal dialysis may induce hyperglycaemia due to glucose-rich dialysate and haemodialysis often causes hypoglycaemia due to the relatively low concentration of glucose in the dialysate. Autonomic neuropathy which is common in chronic kidney disease (CKD) and diabetes increases the risk for asymptomatic hypoglycaemia. Pharmacological options for improving glycaemic control are limited due to alterations to drug metabolism. Impaired glucose tolerance and diabetes are also common in the post-kidney-transplant setting and increase the risk of graft failure and mortality. This review seeks to summarise the literature and tackle the intricacies of glycaemic management in patients with CKD who are either on maintenance haemodialysis or have received a kidney transplant. It outlines changes to glycaemic targets, monitoring of glycaemic control, the use of oral hypoglycaemic agents, the management of severe hyperglycaemia in dialysis and kidney transplantation patients.

Recent advances in new-onset diabetes mellitus after kidney transplantation

A common challenge in managing kidney transplant recipients (KTR) is post-transplant diabetes mellitus (PTDM) or diabetes mellitus (DM) newly diagnosed after transplantation, in addition to known pre-existing DM. PTDM is an important risk factor for post-transplant cardiovascular (CV) disease, which adversely affects patient survival and quality of life. CV disease in KTR may manifest as ischemic heart disease, heart failure, and/or left ventricular hypertrophy. Available therapies for PTDM include most agents currently used to treat type 2 diabetes. More recently, the use of sodium glucose co-transporter 2 inhibitors (SGLT2i), glucagon-like peptide-1 receptor agonists (GLP-1 RA), and dipeptidyl peptidase 4 inhibitors (DPP4i) has cautiously extended to KTR with PTDM, even though KTR are typically excluded from large general population clinical trials. Initial evidence from observational studies seems to indicate that SGLT2i, GLP-1 RA, and DPP4i may be safe and effective for glycemic control in KTR, but their benefit in reducing CV events in this otherwise high-risk population remains unproven. These newer drugs must still be used with care due to the increased propensity of KTR for intravascular volume depletion and acute kidney injury due to diarrhea and their single-kidney status, pre-existing burden of peripheral vascular disease, urinary tract infections due to immunosuppression and a surgically altered urinary tract, erythrocytosis from calcineurin inhibitors, and reduced kidney function from acute or chronic rejection.

Exercise and Prediabetes after Renal Transplantation (EXPRED): Protocol Description

BACKGROUND

Post-transplant diabetes mellitus (PTDM) is a frequent and severe complication after renal transplantation. In fact, PTDM is a risk factor for both infection and cardiovascular diseases. The prevalence and incidence of PTDM have a bimodal evolution: early (up to 3 months) and late PTDM (beyond 12 months). The majority of late PTDM occurs in subjects with prediabetes after transplantation. So, treating patients with prediabetes, a potentially reversible condition, might help preventing PTDM. In the general population, exercise prevents the evolution from prediabetes to diabetes. However, in renal transplantation, not enough evidence is available in this field.

OBJECTIVES

We designed an exploratory analysis to evaluate the feasibility of exercise to reverse prediabetes as a first step in the design of a trial to prevent PTDM.

METHODS

Only patients with prediabetes beyond 12 months after transplantation with capacity to perform exercise will be included. Prediabetes will be diagnosed based on fasting glucose levels and oral glucose tolerance tests (OGTTs). Patients will be treated with a stepped training intervention, starting with aerobic exercise training (brisk walking, swimming, and cycling) 5 times per week and 30 min/day. Aerobic exercise training will be gradually increased to 60 min/day or eventually combined with anaerobic exercise training in case of persistent prediabetes. The reversibility/persistence of prediabetes will be measured with fasting glucose and OGTTs every 3 months. This study will last for 12 months.

Insulin Secretion and Insulin Resistance Trajectories over 1 Year after Kidney Transplantation: A Multicenter Prospective Cohort Study

BACKGROUND

We investigated the changing patterns of insulin secretion and resistance and risk factors contributing to the development of post-transplant diabetes mellitus (PTDM) in kidney recipients under tacrolimus-based immunosuppression regimen during 1 year after transplantation.

METHODS

This was a multicenter prospective cohort study. Of the 168 subjects enrolled in this study, we analyzed a total 87 kidney transplant recipients without diabetes which was assessed by oral glucose tolerance test before transplantation. We evaluated the incidence of PTDM and followed up the index of insulin secretion (insulinogenic index [IGI]) and resistance (homeostatic model assessment for insulin resistance [HOMA-IR]) at 3, 6, 9 months, and 1 year after transplantation by oral glucose tolerance test and diabetes treatment. We also assessed the risk factors for incident PTDM.

RESULTS

PTDM developed in 23 of 87 subjects (26.4%) during 1 year after transplantation. More than half of total PTDM (56.5%) occurred in the first 3 months after transplantation. During 1 year after transplantation, insulin resistance (HOMA-IR) was increased in both PTDM and no PTDM group. In no PTDM group, the increase in insulin secretory function to overcome insulin resistance was also observed. However, PTDM group showed no increase in insulin secretion function (IGI). Old age, status of prediabetes and episode of acute rejection were significantly associated with the development of PTDM.

CONCLUSION

In tacrolimus-based immunosuppressive drugs regimen, impaired insulin secretory function for reduced insulin sensitivity contributed to the development of PTDM than insulin resistance during 1 year after transplantation.

Differential Effects of Voclosporin and Tacrolimus on Insulin Secretion From Human Islets

The incidence of new onset diabetes after transplant (NODAT) has increased over the past decade, likely due to calcineurin inhibitor-based immunosuppressants, including tacrolimus (TAC) and cyclosporin. Voclosporin (VCS), a next-generation calcineurin inhibitor, is reported to cause fewer incidences of NODAT but the reason is unclear. While calcineurin signaling plays important roles in pancreatic β-cell survival, proliferation, and function, its effects on human β-cells remain understudied. In particular, we do not understand why some calcineurin inhibitors have more profound effects on the incidence of NODAT. We compared the effects of TAC and VCS on the dynamics of insulin secretory function, programmed cell death rate, and the transcriptomic profile of human islets. We studied 2 clinically relevant doses of TAC (10 ng/mL, 30 ng/mL) and VCS (20 ng/mL, 60 ng/mL), meant to approximate the clinical trough and peak concentrations. TAC, but not VCS, caused a significant impairment of 15 mM glucose-stimulated and 30 mM KCl-stimulated insulin secretion. This points to molecular defects in the distal stages of exocytosis after voltage-gated Ca2+ entry. No significant effects on islet cell survival or total insulin content were identified. RNA sequencing showed that TAC significantly decreased the expression of 17 genes, including direct and indirect regulators of exocytosis (SYT16, TBC1D30, PCK1, SMOC1, SYT5, PDK4, and CREM), whereas VCS has less broad, and milder, effects on gene expression. Clinically relevant doses of TAC, but not VCS, directly inhibit insulin secretion from human islets, likely via transcriptional control of exocytosis machinery.

Evaluation of Tacrolimus Trough Level in Patients Who Developed Post-transplant Diabetes Mellitus After Kidney Transplantation: A Retrospective Single-Center Study in Saudi Arabia

BACKGROUND

Post-transplant diabetes mellitus (PTDM) is a complication after kidney transplantation. Studies showed an association between high trough levels of tacrolimus FK506 and PTDM. This study aims to investigate the association between FK506 trough levels during the first year after kidney transplant and the incidence of PTDM.

METHODS

This retrospective study included adult kidney transplant patients who were not diabetic before transplantation from 2011 to 2014. The analysis evaluated FK506 trough levels at different time points post-transplant, as well as other variables to determine whether they were associated with PTDM.

RESULTS

The cumulative incidence of PTDM was 22.5% with a median time to PTDM diagnosis of 10 months. PTDM patients had higher first FK506 (ng/mL) levels (P = .001), and more patients in the PTDM group had FK506 level >10 ng/mL during the first 3 months (P = .004). After 12 months of transplant, PTDM patients had higher body mass index (BMI) 28.3 ± 6.9 kg/m² compared to non-PTDM patients 26.4 ± 6.7 kg/m² (P = .015). Binary logistic regression analysis showed that age ≥40 years (odds ratio [OR] = 2.75, P = .004), BMI ≥25 kg/m² (OR = 2.04, P = .040), and FK506 level ≥10 ng/mL during the first 3 months (OR = 2.65, P = .009) were significantly related to PTDM development.

CONCLUSION

Patients with FK506 trough level >10 ng/mL during the first 3 months after transplantation are at higher risk of PTDM, especially in patients >40 years of age and/or who are overweight. These results may strengthen the notion that there is a connection between high FK506 trough levels and PTDM development.

Metabolic Disorders with Kidney Transplant

Metabolic disorders are highly prevalent in kidney transplant candidates and recipients and can adversely affect post-transplant graft outcomes. Management of diabetes, hyperparathyroidism, and obesity presents distinct opportunities to optimize patients both before and after transplant as well as the ability to track objective data over time to assess a patient's ability to partner effectively with the health care team and adhere to complex treatment regimens. Optimization of these particular disorders can most dramatically decrease the risk of surgical and cardiovascular complications post-transplant. Approximately 60% of nondiabetic patients experience hyperglycemia in the immediate post-transplant phase. Multiple risk factors have been identified related to development of new onset diabetes after transplant, and it is estimated that upward of 7%-30% of patients will develop new onset diabetes within the first year post-transplant. There are a number of medications studied in the kidney transplant population for diabetes management, and recent data and the risks and benefits of each regimen should be optimized. Secondary hyperparathyroidism occurs in most patients with CKD and can persist after kidney transplant in up to 66% of patients, despite an initial decrease in parathyroid hormone levels. Parathyroidectomy and medical management are the options for treatment of secondary hyperparathyroidism, but there is no randomized, controlled trial providing clear recommendations for optimal management, and patient-specific factors should be considered. Obesity is the most common metabolic disorder affecting the transplant population in both the pre- and post-transplant phases of care. Not only does obesity have associations and interactions with comorbid illnesses, such as diabetes, dyslipidemia, and cardiovascular disease, all of which increase morbidity and mortality post-transplant, but it also is intimately inter-related with access to transplantation for patients with kidney failure. We review these metabolic disorders and their management, including data in patients with kidney transplants.

Anti-CD40 antibody 2C10 binds to a conformational epitope at the CD40-CD154 interface that is conserved among primate species

The antagonistic anti-CD40 antibody, 2C10, and its recombinant primate derivative, 2C10R4, are potent immunosuppressive antibodies whose utility in allo- and xenotransplantation have been demonstrated in nonhuman primate studies. In this study, we defined the 2C10 binding epitope and found only slight differences in affinity of 2C10 for CD40 derived from four primate species. Staining of truncation mutants mapped the 2C10 binding epitope to the N-terminal portion of CD40. Alanine scanning mutagenesis of the first 60 residues in the CD40 ectodomain highlighted key amino acids important for binding of 2C10 and for binding of the noncross-blocking anti-CD40 antibodies 3A8 and 5D12. All four 2C10-binding residues defined by mutagenesis clustered near the membrane-distal tip of CD40 and partially overlap the CD154 binding surface. In contrast, the overlapping 3A8 and 5D12 epitopes map to an opposing surface away from the CD154 binding domain. This biochemical characterization of 2C10 confirms the validity of nonhuman primate studies in the translation of this therapeutic antibody and provides insight its mechanism of action.

Homeostatic Model Assessment in Kidney Transplantation

INTRODUCTION

Long-term kidney transplantation survival has been limited to cardiovascular-disease-associated death, which may be related to insulin resistance. The aim of this study is to evaluate the association between homeostatic model assessment (HOMA) and renal graft function.

MATERIALS AND METHODS

From January 2013 to March 2015, 55 nondiabetic kidney recipients were reviewed retrospectively with their baseline fasting serum insulin and glucose levels as the basis the following indexes: 1. HOMA insulin resistance (HOMA-IR), 2. HOMA-β, and 3. insulin-glucose ratio (IGR). These patients were divided into 2 groups according to their HOMA indexes, and the serum creatinine (Cr) and estimated glomerular filtration rate (eGFR) were analyzed on the basis of every 6 months up to 3 years after kidney transplantation. Finally, we evaluate whether these HOMA indexes are a determinant factor of eGFR at post-transplant 1 year, 2 year, and 3 year.

RESULTS

There was no persisting difference in Cr and eGFR between high- and low-HOMA indexes except that the Cr and eGFR difference by HOMA-β stratification increased with time and became nearly significant at 3 years after transplantation. Further univariate and multivariate linear regression models showed no factor affected the 1-year eGFR independently, while weight affected the 2-year eGFR and only HOMA-β affected the 3-year eGFR independently.

CONCLUSION

In non-diabetic kidney recipients, the eGFR difference between high- and low-HOMA-β patients increases over time. In multivariate linear regression, HOMA-β, but not HOMA-IR nor IGR, has independent significant association with eGFR at 3 years after transplantation.

Post-transplantation diabetes in kidney transplant recipients: an update on management and prevention

Post-transplantation diabetes mellitus (PTDM) may severely impact both short- and long-term outcomes of kidney transplant recipients in terms of graft and patient survival. However, PTDM often goes undiagnosed is underestimated or poorly managed. A diagnosis of PTDM should be delayed until the patient is on stable maintenance doses of immunosuppressive drugs, with stable kidney graft function and in the absence of acute infections. Risk factors for PTDM should be assessed during the pre-transplant evaluation period, in order to reduce the likelihood of developing diabetes. The oral glucose tolerance test is considered as the gold standard for diagnosing PTDM, whereas HbA1c is not reliable during the first months after transplantation. Glycaemic targets should be individualised, and comorbidities such as dyslipidaemia and hypertension should be treated with drugs that have the least possible impact on glucose metabolism, at doses that do not interact with immunosuppressants. While insulin is the preferred agent for treating inpatient hyperglycaemia in the immediate post-transplantation period, little evidence is available to guide therapeutic choices in the management of PTDM. Metformin and incretins may offer some advantage over other glucose-lowering agents, particularly with respect to risk of hypoglycaemia and weight gain. Tailoring immunosuppressive regimens may be of help, although maintenance of good kidney function should be prioritised over prevention/treatment of PTDM. The aim of this narrative review is to provide an overview of the available evidence on management and prevention of PTDM, with a focus on the available therapeutic options.

Pretransplantation Oral Glucose Tolerance Test Can Prevent Posttransplant Diabetes Mellitus After Renal Transplantation: Preliminary Study

Posttransplant diabetes mellitus (PTDM) adversely affects renal graft and patient survival. Fasting plasma glucose (FPG) alone underestimates diagnosis of glucose metabolism disorders (GMD) detected using the oral glucose tolerance test (OGTT-75). Prediabetes including impaired fasting glucose (IFG): 100 to 125 mg/dL (5.6-6.9 mmol/L) and impaired glucose tolerance (IGT): 140 to 199 mg/dL (7.8-11 mmol/L) 2 hours post 75-g OGTT in the pretransplant period can have a connection with the occurrence of PTDM after renal transplantation (RTx). The aim of our study was to assess the benefit of performing OGTT-75 in dialyzed chronic kidney disease (stage 5) patients on the waiting list for kidney transplantation as a useful tool to prevent PTDM.

MATERIALS AND METHODS

Pretransplant glucose testing using OGTT-75 was performed in nondiabetic dialyzed chronic kidney disease patients on the waiting list for renal transplantation in the southwest region of Poland. GMD were diagnosed according to current criteria. Patients with recognized prediabetic stage were recommended a low carbohydrate diet, lifestyle modification, and increased physical activity. In the 12-month posttransplant period we estimated the prevalence of PTDM in the study group based on FPG >126 mg/dL (7 mmol/L) in 2 measurements or random blood glucose >200 mg/dL (11.1 mmol/L).

RESULTS

A total of 80 nondiabetic dialysis patients (65 hemodialysis/15 peritoneal dialysis; 47 male/33 female) met initial entry criteria. In pretransplant glucose testing prediabetes was found in 31 out of 80 patients (39%). Among them, 5 patients (6.25%) had combined IGT/IFG, 18 patients (22.5%) had IGT, and 8 patients (10%) had IFG. One year after RTx we recognized PTDM in 14% of all analyzed patients (11/80) and noticed a significant frequency of glucose disorders status change after RTx (P  =  .002).

CONCLUSION

Our findings suggest early detection of prediabetes using the OGTT-75 test in nondiabetic dialysis patients waiting for RTx to prevent occurrence of PTDM.

Association of Body Mass Index and the Risk of New-Onset Diabetes After Kidney Transplantation: A Meta-analysis

OBJECTIVE

To comprehensively examine the correlation between body mass index (BMI) and the risk of new-onset diabetes after kidney transplantation (NODAT).

METHODS

The electronic databases Pubmed, Embase, and Cochrane Library, updated in December 2016, were searched, and a literature review was conducted as well to identify relevant research studies. With the use of R 3.12 software, the association between BMI and NODAT risk was analyzed by means of a meta-analysis, with the mean differences (MDs) and their 95% confidence intervals (CIs) as effect indexes. Publication bias was assessed with the use of the Egger test. A sensitivity analysis was performed by excluding 1 study at a time. And the overall morbidity of NODAT was calculated.

RESULTS

In the meta-analysis, 55 eligible studies involving 15,458 kidney transplantation cases were included. After the heterogeneity test, the random-effects model was used to calculate the pooled results of the effect indexes. The results of the meta-analysis showed that BMI was an independent risk factor of NODAT (MD, 1.88; 95% CI, 1.48-2.27). No publication bias was found among the included studies (t = 0.3417; P = 0.7339). The sensitivity analysis revealed that the pooled MD did not reverse after ignoring 1 study at a time. In addition, the overall morbidity of NODAT was 21% (95% CI, 21%-23%).

CONCLUSIONS

Our results suggest that BMI is an independent risk factor for NODAT.

Incidence of cardiovascular events and associated risk factors in kidney transplant patients: a competing risks survival analysis

BACKGROUND

The high prevalence of cardiovascular risk factors among the renal transplant population accounts for increased mortality. The aim of this study is to determine the incidence of cardiovascular events and factors associated with cardiovascular events in these patients.

METHODS

An observational ambispective follow-up study of renal transplant recipients (n = 2029) in the health district of A Coruña (Spain) during the period 1981-2011 was completed. Competing risk survival analysis methods were applied to estimate the cumulative incidence of developing cardiovascular events over time and to identify which characteristics were associated with the risk of these events. Post-transplant cardiovascular events are defined as the presence of myocardial infarction, invasive coronary artery therapy, cerebral vascular events, new-onset angina, congestive heart failure, rhythm disturbances, peripheral vascular disease and cardiovascular disease and death. The cause of death was identified through the medical history and death certificate using ICD9 (390-459, except: 427.5, 435, 446, 459.0).

RESULTS

The mean age of patients at the time of transplantation was 47.0 ± 14.2 years; 62% were male. 16.5% had suffered some cardiovascular disease prior to transplantation and 9.7% had suffered a cardiovascular event. The mean follow-up period for the patients with cardiovascular event was 3.5 ± 4.3 years. Applying competing risk methodology, it was observed that the accumulated incidence of the event was 5.0% one year after transplantation, 8.1% after five years, and 11.9% after ten years. After applying multivariate models, the variables with an independent effect for predicting cardiovascular events are: male sex, age of recipient, previous cardiovascular disorders, pre-transplant smoking and post-transplant diabetes.

CONCLUSIONS

This study makes it possible to determine in kidney transplant patients, taking into account competitive events, the incidence of post-transplant cardiovascular events and the risk factors of these events. Modifiable risk factors are identified, owing to which, changes in said factors would have a bearing of the incidence of events.

The effective bioengineering method of implantation decellularized renal extracellular matrix scaffolds

End stage renal disease (ESRD) is a progressive loss of kidney function with a high rate of morbidity and mortality. Transplantable organs are hard to come by and hold a high risk of recipient immune rejection. We intended to establish a more effective and faster method to decellularize and recellularize the kidney scaffold for transplant and regeneration. We successfully produced renal scaffolds by decellularizing rat kidneys with 0.5% sodium dodecyl sulfate (SDS), while still preserving the extracellular matrix (ECM) 3D architecture, an intact vascular tree and biochemical components. We recellularized the kidney scaffolds with mouse embryonic stem (ES) cells that then populated and proliferated within the glomerular, vascular, and tubular structures. After in vivo implantation, these recellularized scaffolds were easily reperfused, tolerated blood pressure and produced urine with no blood leakage. Our methods can successfully decellularize and recellularize rat kidneys to produce functional renal ECM scaffolds. These scaffolds maintain their basic components, retain intact vasculature and show promise for kidney regeneration.

Reduction in new-onset diabetes mellitus after renal transplant with erythropoietin-stimulating agents: a retrospective cohort study

BACKGROUND

Studies have shown that erythropoietin-stimulating agents (ESAs) protect mice against the development of diabetes through direct effects on pancreatic ß cells. However, the effect of ESAs on the incidence of diabetes in humans has not been well studied. It is unknown whether exposure to ESAs is associated with a reduced incidence of new-onset diabetes after transplant (NODAT).

OBJECTIVE

The objective of this study is to examine the relationship between ESA exposure post-renal transplant and the development of NODAT.

DESIGN

We performed a single center, retrospective cohort analysis.

PATIENTS

We compared patients who received a first live or deceased donor renal allograft, with any exposure to an ESA vs. those without such exposure and who developed NODAT and who did not. Patients with a prior history of diabetes mellitus or multi-organ transplant, including a second renal transplant were excluded.

MEASUREMENTS AND METHODS

NODAT was defined based on the 2008 Canadian Diabetes Association criteria. Multivariate logistic regression analysis was performed to determine factors independently associated with NODAT.

RESULTS

One hundred thirty-two (29 %) patients were exposed to an ESA, four of which developed NODAT compared to 128 who did not develop NODAT (p < 0.0001). Of those not exposed to an ESA, 15 % (48/319) developed NODAT. By Fisher's exact test, exposure to an ESA at any time post-transplant reduced the risk of developing NODAT; odds ratio (OR) = 0.08, 95 % confidence interval (CI) (0.018-0.352), p = 0.0008. Older age; OR = 1.41, 95 % CI (1.036-1.933), p < 0.02, higher random blood sugar at discharge; OR = 1.30, 95 % CI (1.077-1.57), p < 0.006 and deceased donor; OR 2.18 CI (1.009-4.729), p = 0.04 were associated with an increased risk of NODAT.

LIMITATIONS

The limitations of this study include its retrospective nature, single center, and homogenous population; thus, generalizability of the results must be approached with caution.

CONCLUSION

ESA exposure may be associated with a reduced incidence of NODAT in the post-renal transplant population. The role of ESA in preventing NODAT requires further investigation.

Tacrolimus-Induced Diabetic Ketoacidosis and Effect of Switching to Everolimus: A Case Report

BACKGROUND

New-onset diabetes after transplantation (NODAT) is a common metabolic complication. Most conventional immunosuppressive medications, especially steroids and tacrolimus, are responsible for its development. NODAT may rarely be associated with severe, life-threating complications in kidney transplantation recipients.

CASE REPORT

A 44-year-old man was admitted to our polyclinic for a routine post kidney transplantation visit. He reported polyuria, polydipsia, and general weakness. The patient had undergone preemptive, living-related kidney transplantation 5 weeks previously. Immunosuppressive treatment comprised tacrolimus, prednisolone, and mycophenolate mofetil. Physical examination revealed no abnormalities except signs of mild dehydration. Although he had no history of diabetes before kidney transplantation and his serum fasting glucose levels were within the reference range at the follow-up visits, his laboratory tests revealed high serum glucose and creatinine levels, ketosis, and metabolic acidosis. Our diagnosis was NODAT with diabetic ketoacidosis and prerenal azotemia. Initial treatment comprised intravenous saline and insulin infusion and subsequently involved intensive subcutaneous insulin administration. Despite the intensive insulin therapy and reduction of the tacrolimus dose, sufficient glucose regulation was not achieved. Tacrolimus was switched to everolimus on day 6 of hospitalization. The patient's insulin requirement gradually decreased to one-half of the primary dose over the following several days, and he was discharged on day 10 with successful serum glucose regulation. Although the diabetogenic potential of sirolimus is similar to that of tacrolimus, the impact of everolimus on glucose metabolism remains unclear.

CONCLUSIONS

We have reported a life-threating metabolic complication associated with tacrolimus and successful treatment of NODAT by switching from tacrolimus to everolimus.

Post-Transplant Diabetes Mellitus: Causes, Treatment, and Impact on Outcomes

Post-transplant diabetes mellitus (PTDM) is a frequent consequence of solid organ transplantation. PTDM has been associated with greater mortality and increased infections in different transplant groups using different diagnostic criteria. An international consensus panel recommended a consistent set of guidelines in 2003 based on American Diabetes Association glucose criteria but did not exclude the immediate post-transplant hospitalization when many patients receive large doses of corticosteroids. Greater glucose monitoring during all hospitalizations has revealed significant glucose intolerance in the majority of recipients immediately after transplant. As a result, the international consensus panel reviewed its earlier guidelines and recommended delaying screening and diagnosis of PTDM until the recipient is on stable doses of immunosuppression after discharge from initial transplant hospitalization. The group cautioned that whereas hemoglobin A1C has been adopted as a diagnostic criterion by many, it is not reliable as the sole diabetes screening method during the first year after transplant. Risk factors for PTDM include many of the immunosuppressant medications themselves as well as those for type 2 diabetes. The provider managing diabetes and associated dyslipidemia and hypertension after transplant must be careful of the greater risk for drug-drug interactions and infections with immunosuppressant medications. Treatment goals and therapies must consider the greater risk for fluctuating and reduced kidney function, which can cause hypoglycemia. Research is actively focused on strategies to prevent PTDM, but until strategies are found, it is imperative that immunosuppression regimens are chosen based on their evidence to prolong graft survival, not to avoid PTDM.

Impact of Resistance Training on Factors Involved in the Development of New-Onset Diabetes After Transplantation in Renal Transplant Recipients: An Open Randomized Pilot Study

OBJECTIVES

New-onsetdiabetes after transplant (NODAT) is a major contributor to cardiovascular disease after transplantation. Kidney transplantation (KT) recipients have low levels of exercise capacity. Resistance training (RT) might be of special benefit in this population because underlying disease and immunosuppressive drugs favour muscle loss and insulin resistance. The aim of this study was to assess the feasibility of implementing an RT program within a population of KT recipients and its impact on the incidence of NODAT and cardiometabolic risk factors.

METHODS

This pilot study was an open-randomized study. We randomized 24 patients with a 1:1 allocation to 2 parallel groups, the exercise group (E) or the control group (C). The E group was submitted to RT 3 times a week for 16 weeks. Anthropometric, body composition, cardiometabolic risk factors, muscle strength, cardiorespiratory fitness and well-being were measured before and after 16 weeks.

RESULTS

Of the 24 recruited participants, 20 completed the study (10 in the E group and 10 in the C group). No injuries were reported. The intervention was associated with a significant increase in muscle strength (p=0.003). A significant group effect, in favour of the E group, was detected for the well-being score (p=0.03). However, no changes in body composition, cardiometabolic risk factors or cardiorespiratory fitness were noted for either group after the intervention.

CONCLUSIONS

This pilot study suggests that RT appears to be secure and feasible and improves strength and well-being in patients after KT. However, it does not improve cardiometabolic risk factors.

Porcine kidneys as a source of ECM scaffold for kidney regeneration

OBJECTIVE

To produce and examine decellularized kidney scaffolds from porcine as a platform for kidney regeneration research.

METHODS

Porcine kidneys were decellularized with sodium dodecyl sulfate solution and Triton X-100 after the blood was rinsed. Then the renal ECM scaffolds were examined for vascular imaging, histology to investigate the vascular patency, degree of decellularization.

RESULTS

Renal ECM scaffolds of porcine kidneys were successfully produced. Decellularized renal scaffolds retained intact microarchitecture including the renal vasculature and essential extracellular matrix components.

CONCLUSION

We have developed an excellent decellularization method that can be used in large organs. These scaffolds maintain their basic components, and show intact vasculature system. This represents a step toward development of a transplantable organ using tissue engineering techniques.

The effect of magnesium supplements on early post-transplantation glucose metabolism: a randomized controlled trial

Post-transplantation hypomagnesemia is common and predicts diabetes. Magnesium improves glycemic control in diabetics and insulin sensitivity in insulin resistant subjects. We aimed to assess the effectiveness of oral magnesium for improving glycemic control and insulin sensitivity at 3 months post-transplantation. We conducted a single-center, open-label, randomized parallel group study. We included adults with serum magnesium <1.7 mg/dl within 2 weeks after kidney transplantation. We randomized participants to 450 mg magnesium oxide up to three times daily or no treatment. The primary endpoint was the mean difference in fasting glycemia. Secondary endpoints were the mean difference in area under the curve (AUC) of glucose during an oral glucose tolerance test and insulin resistance measured by Homeostasis Model of Assessment-Insulin Resistance (HOMA-IR). Analyses were on intention-to-treat basis. In patients randomized to magnesium oxide (N = 27) versus no treatment (N = 27), fasting glycemia on average was 11.5 mg/dl lower (95% CI 1.7 to 21.3; P = 0.02). There was no difference between the two groups neither for 2 h AUC, where the mean value was 1164 mg/dl/min (95% CI -1884 to 4284; P = 0.45) lower in the treatment group nor for HOMA-IR. Magnesium supplements modestly improved fasting glycemia without effect on insulin resistance. Higher baseline glycemia among patients in the control group may have driven the positive outcome (ClinicalTrials.gov number: NCT01889576).

Lower magnesium level associated with new-onset diabetes and pre-diabetes after kidney transplantation

BACKGROUND

Hypomagnesemia is associated with increased peripheral insulin resistance in the general population. It is frequently seen after renal transplantation. We examined its role as a risk factor for new-onset diabetes after transplantation (NODAT) and new-onset pre-diabetes after transplantation (NOPDAT).

METHODS

A retrospective analysis of 138 previously non-diabetic renal transplant recipients was conducted. Cox and logistic regression analyses were performed to examine the associations between 1-month post-transplant serum magnesium level and subsequent diagnoses of NODAT/NOPDAT.

RESULTS

NODAT was diagnosed in 34 (24.6 %) and NOPDAT in 12 (8.7 %) patients. Median time to diagnosis of NODAT/NOPDAT was 20.4 months (interquartile range [IQR] 6.8-34.8). Median follow up for the entire group was 3.5 years (IQR 2.3-5.6). Mean magnesium level at 1 month after transplantation was significantly lower in patients subsequently diagnosed with NODAT/NOPDAT (1.60 ± 0.27 vs. 1.76 ± 0.29 mg/dl, p = 0.002). Cox regression analysis identified a trend towards developing NODAT/NOPDAT with lower baseline magnesium levels (hazard ratio 0.89 per 0.1 mg/dl increment in magnesium level, 95 % confidence interval [CI] = 0.78-1.01, p = 0.07); a stronger relationship between the two variables was seen at logistic regression analysis (odds ratio 0.81 per 0.1 mg/dl increment in serum magnesium (95 % CI 0.67-0.98, p = 0.03).

CONCLUSIONS

A lower magnesium level at 1 month after transplantation may be predictive of a subsequent diagnosis of glucose intolerance or diabetes in renal transplant recipients. Whether replenishing magnesium stores can prevent development of these disorders requires further investigation.

Tacrolimus and sirolimus have distinct effects on insulin signaling in male and female rats

Although the contribution of the immunosuppressants tacrolimus (TAC) and sirolimus (SIR) to the development of posttransplant diabetes mellitus (PTDM) are being increasingly recognized, the mechanisms of immunosuppressant-induced hyperglycemia are unclear. SIR induces insulin resistance predominantly, but is associated with β-cell dysfunction in rodents. TAC affects islet function but is associated with worsening insulin sensitivity in a few, and improvement in some, clinical studies. We sought to clarify the contributions of TAC and SIR to insulin resistance and islet function. Four groups of male and female Sprague-Dawley rats received TAC, SIR, TAC and SIR, or control for 2 weeks. All rats were administered an oral glucose challenge at the end of treatment. Half the groups were sacrificed 10 minutes after administration of regular insulin whereas the other half did not receive insulin before sacrifice. Liver, pancreas, fat, and muscle were harvested subsequently. Quantification of Western blots revealed that SIR and TAC plus SIR suppressed the phospho-Akt (pAkt)-to-Akt ratios in liver, muscle, and fat compared with control, regardless of sex. TAC alone did not impair the pAkt-to-Akt ratios in any of the tissues in male and female rats. β-Cell mass was reduced significantly after TAC treatment in male rats. SIR did not affect β-cell mass, regardless of sex. Our study demonstrated very clearly that SIR impairs insulin signaling, without any effect on β-cell mass, and TAC does not impair insulin signaling but reduces β-cell mass. Our efforts are key to understanding the mechanisms of immunosuppressant-induced hyperglycemia and to tailoring treatments for PTDM.

Efficacy and safety of sitagliptin for the treatment of new-onset diabetes after renal transplantation

New-onset diabetes after transplantation (NODAT) is a common comorbidity after renal transplantation. Though metformin is the first-line agent for the treatment of type 2 diabetes, in renal transplant recipients, metformin is frequently avoided due to concerns about renal dysfunction and risk for lactic acidosis. Therefore, alternative first-line agents for the treatment of NODAT in renal transplant recipients are needed. Sitagliptin, a dipeptidyl-peptidase-4 (DPP-4) inhibitor, has a low incidence of hypoglycemia, is weight neutral, and, in a small study, did not affect immunosuppressant levels. However, long-term sitagliptin use for the treatment of NODAT in kidney transplant recipients has not been studied. We retrospectively analyzed renal transplant recipients diagnosed with NODAT and treated with sitagliptin to assess safety and efficacy. Twenty-two patients were started on sitagliptin alone. After 12 months of followup, 19/22 patients remained on sitagliptin alone with a significant improvement in hemoglobin A1c. Renal function and immunosuppressant levels remained stable. Analysis of long-term followup (32.5 ± 17.8 months) revealed that 17/22 patients remained on sitagliptin (mean hemoglobin A1c < 7%) with 9/17 patients remaining on sitagliptin alone. Transplant-specific adverse events were rare. Sitagliptin appears safe and efficacious for the treatment of NODAT in kidney transplant recipients.

The higher diabetogenic risk of tacrolimus depends on pre-existing insulin resistance. A study in obese and lean Zucker rats

Insulin resistance may interact with calcineurin inhibitors, enhancing the diabetogenic effect of tacrolimus compared with cyclosporine-A. We studied both drugs in insulin-resistant animals: obese Zucker rats (n = 45), and insulin-sensitive animals: lean Zucker rats (n = 21). During 11 days, animals received saline-buffer, cyclosporine-A (2.5 mg/kg/day) or tacrolimus (0.3 mg/kg/day). At Days 0 and 12 animals underwent intraperitoneal glucose tolerance test (0-30-60-120 min). Islet morphometry, beta-cell proliferation, apoptosis and Ins2 gene expression were analyzed. By Day 12, no lean animal had developed diabetes, while all obese animals on tacrolimus and 40% on cyclosporine-A had. In obese animals, tacrolimus reduced beta-cell proliferation and Ins2 gene expression compared with cyclosporine-A. Five days after treatment discontinuation, partial recovery was observed, with only 10% and 60% of the animals on cyclosporine and tacrolimus remaining diabetic respectively. Beta-cell proliferation increased in animals on tacrolimus while Ins2 gene expression remained unaltered. In conclusion, insulin resistance exacerbated the diabetogenic effect of tacrolimus compared with cyclosporine-A. This may be explained by greater inhibition of Ins2 gene and beta-cell proliferation by tacrolimus in the insulin resistant state. Discontinuation of the drugs may allow the recovery of the metabolic alterations.

Vildagliptin and pioglitazone in patients with impaired glucose tolerance after kidney transplantation: a randomized, placebo-controlled clinical trial

BACKGROUND

New-onset diabetes after transplantation (NODAT) is a serious complication after kidney transplantation affecting graft and patient survival. Currently, no guidelines exist for the management of renal transplant patients with impaired glucose tolerance (IGT), a risk factor for the development of NODAT and an independent predictor of death.

METHODS

In a population of 48 stable renal transplant recipients at least 6 months from time of transplantation with newly diagnosed IGT, we tested the dipeptidylpeptidase-4 inhibitor vildagliptin, the thiazolidinedione pioglitazone, or placebo for 3 months in addition to lifestyle counseling. Outcome measures were difference in change in oral glucose tolerance test between the groups and between baseline and end of study as well as change in HbA1c, serum lipids, and renal and hepatic function.

RESULTS

In both treatment groups, 2-hr plasma glucose at 3 months was significantly reduced compared with baseline (vildagliptin: -20±24 mg/dL; P=0.002 and pioglitazone: -23±29 mg/dL; P=0.004), and pioglitazone also significantly improved fasting plasma glucose (-11±14 mg/dL; P=0.003), although the primary outcome (difference in change in 2-hr plasma glucose among the three groups) did not reach statistical significance. Furthermore, HbA1c was decreased in both treatment arms (vildagliptin: -0.1%±0.3%; P=0.046 and pioglitazone: -0.2%±0.3%; P=0.029). In the placebo group, no significant changes in these parameters were observed. Only mild adverse events occurred and at a similar rate in all three groups.

CONCLUSIONS

These data demonstrate that both vildagliptin and pioglitazone are of potential benefit in patients with IGT after renal transplantation in addition to lifestyle modification.

Metformin improves immunosuppressant induced hyperglycemia and exocrine apoptosis in rats

BACKGROUND

Immunosuppressants are an important cause of posttransplantation diabetes mellitus. We have shown that tacrolimus and sirolimus induce hyperglycemia and hyperinsulinemia in normal rats. We hypothesized that metformin, given concurrently with tacrolimus and/or sirolimus, prevents disturbances in glucose and insulin metabolism.

METHODS

Eight groups (n=6) of normal Sprague-Dawley rats were studied: four groups received tacrolimus, sirolimus, tacrolimus/sirolimus, or control for 14 days, and four more groups received similar treatments along with metformin. Daily glucoses were measured. All rats were administered an oral glucose challenge before sacrifice. Pancreata were analyzed by terminal deoxynucleotide tranferase-mediated dUTP nick-end labeling staining and immunohistochemistry.

RESULTS

Tacrolimus, sirolimus, and tacrolimus/sirolimus impaired glucose tolerance compared to control. Sirolimus and tacrolimus/sirolimus also increased random blood glucose levels. Sirolimus alone resulted in hyperinsulinemia after oral glucose challenge compared to control. In the sirolimus/metformin and tacrolimus/sirolimus/metformin groups, mean daily random glucose was no longer increased, although the response to glucose challenge was still impaired. Metformin decreased pancreatic exocrine and trended to decrease endocrine apoptosis in tacrolimus/sirolimus group and reduced islet insulin content in sirolimus group.

CONCLUSIONS

This is the first study to show that metformin can improve immunosuppressant-induced hyperglycemia, when administered concurrently, and reduces exocrine apoptosis (reducing the impact on potential islet progenitor cells).

Decellularization methods of porcine kidneys for whole organ engineering using a high-throughput system

End-stage renal failure is a devastating disease, with donor organ transplantation as the only functional restorative treatment. The current number of donor organs meets less than one-fifth of demand, so regenerative medicine approaches have been proposed as potential therapeutic alternatives. One such approach for whole large-organ bioengineering is to combine functional renal cells with a decellularized porcine kidney scaffold. The efficacy of cellular removal and biocompatibility of the preserved porcine matrices, as well as scaffold reproducibility, are critical to the success of this approach. We evaluated the effectiveness of 0.25 and 0.5% sodium dodecyl sulfate (SDS) and 1% Triton X-100 in the decellularization of adult porcine kidneys. To perform the decellularization, a high-throughput system was designed and constructed. In this study all three methods examined showed significant cellular removal, but 0.5% SDS was the most effective detergent (<50 ng DNA/mg dry tissue). Decellularized organs retained intact microarchitecture including the renal vasculature and essential extracellular matrix components. The SDS-treated decellularized scaffolds were non-cytotoxic to primary human renal cells. This method ensures clearance of porcine cellular material (which directly impacts immunoreactivity during transplantation) and preserves the extracellular matrix and cellular compatibility of these renal scaffolds. Thus, we have developed a rapid decellularization method that can be scaled up for use in other large organs, and this represents a step toward development of a transplantable organ using tissue engineering techniques.

Prevalence and risk factors of pre-diabetes after renal transplantation: a single-centre cohort study in 200 consecutive patients

BACKGROUND

After renal transplantation, patients are prone to develop impairments in glucose metabolism. In 2005, the American Diabetes Association published new guidelines on the diagnosis of pre-diabetes [plasma glucose levels from 100 to 125 mg/dL fasting or from 140 to 199 mg/dL 2 h after an oral glucose tolerance test (OGTT)]. This study sought to evaluate the prevalence and the potentially associated factors of pre-diabetes in a cohort of renal transplant patients on maintenance immunosuppressive medication. Furthermore, the diagnostic value of HbA1-c measurements in predicting pre-diabetes in transplant patients is undetermined.

METHODS

Two hundred consecutive renal transplant patients of our outpatient transplant clinic were evaluated using a standard OGTT. On the day of testing, multiple factors presumably associated with pre-diabetes were assessed via a standardized questionnaire: daily steroid dosage, triglyceride levels, cholesterol levels, estimated glomerular filtration rate (eGFR) [abbreviated Modification of Diet in Renal Disease (MDRD) formula], systolic and diastolic blood pressure, pulse pressure, age, gender, body mass index (BMI), BMI <>30 and <>25, number of renal transplants, number of rejection episodes prior to testing, source of renal transplant, cause of renal failure and medications as related to the prescription of cyclosporine, tacrolimus, mycophenolate mophetil, angiotensin-converting enzyme inhibitors, AT1-blockers, statins, β-blockers and thiazide diuretics. Patients diagnosed with pre-diabetes were compared to subjects with normal test results. Fishers exact test and the Wilcoxon rank-sum test were applied to compare the two study populations, whereas multivariate logistic regression was used to seek potential risk factors as related to other covariates. Risk ratios (RRs) to develop pre-diabetes were calculated for significant variables.

RESULTS

Ten patients had results indicative of post-transplant diabetes whereas data sets of three other patients were incomplete and were thus not included in the analysis. From the remaining 187 patients, 130 (69.5%) displayed normal test results whereas 57 (30.5%) had results indicative of pre-diabetes. On multivariate regression analysis, patients with pre-diabetes were significantly older {55.3 ± 12.1 versus 47.7 ± 12.6 years, P = 0.0007, RRs per 5 years increase 1.28 [95% confidence interval (95% CI) 1.11-1.47]}, had more rejection episodes [0.26 ± 0.48 versus 0.12 ± 0.37, P = 0.0024, RRs per rejection episode 3.99 (95% CI 1.63-9.77)] and showed lower diastolic blood pressure readings [77 ± 10 mmHg versus 81 ± 10 mmHg, P = 0.0362, RR per 5 mmHg decrease 1.14 (95% CI 1.04-1.49)].

CONCLUSIONS

There is a high incidence of latent pre-diabetes among renal transplant recipients. Increasing age, rejection episodes and lower diastolic blood pressure proved to be associated with pre-diabetes. In contrast to post-transplant diabetes, tacrolimus use and HbA1-c levels were not prognostic of pre-diabetes.

New-onset diabetes after kidney transplantation-changes and challenges

Despite substantial improvement in short-term results after kidney transplantation, increases in long-term graft survival have been modest. A significant impediment has been the morbidity and mortality attributable to cardiovascular disease (CVD). New-onset diabetes after transplantation (NODAT) is an independent predictor of cardiovascular events. This review examines recent literature surrounding diagnosis, outcomes and management of NODAT. Amongst otherwise heterogeneous studies, a common finding is the relative insensitivity of fasting blood glucose (FBG) as a screening test. Incorporating self-testing of afternoon capillary BG and glycohemoglobin (HbA(1c) ) detects many cases that would otherwise remain undetected without the oral glucose tolerance test (OGTT). Assessing the impact of NODAT on patient and graft survival is complicated by changes to diagnostic criteria, evolution of immunosuppressive regimens and increasing attention to cardiovascular risk management. Although recent studies reinforce a link between NODAT and death with a functioning graft (DWFG), there seems to be little effect on death-censored graft loss. The significance of glycemic control and diabetes resolution for patient outcomes remain notably absent from NODAT literature and treatment is also a neglected area. This review examines new and old therapeutic options, emphasizing the need to assess β-cell pathology in customizing therapy. Finally, areas warranting further research are considered.

Tacrolimus and sirolimus induce reproductive abnormalities in female rats

BACKGROUND

Immunosuppression medications contribute to posttransplant diabetes mellitus in patients and can cause insulin resistance in male rats. Tacrolimus (TAC)-sirolimus (SIR) immunosuppression is also associated with appearance of ovarian cysts in transplant patients. Because insulin resistance is observed in patients with polycystic ovary syndrome, we hypothesized that TAC or SIR may induce reproductive abnormalities.

METHODS

We monitored estrus cycles of adult female rats treated daily with TAC, SIR, and combination of TAC-SIR, or diluent (control) for 4 weeks. Animals were then challenged with oral glucose to determine their glucose and insulin responses, killed, and their blood and tissues, including ovaries and uteri harvested.

RESULTS

TAC and TAC-SIR treatments increased mean random glucose concentrations (P<0.05). TAC, SIR, and TAC-SIR treatments also increased the glucose response to oral glucose challenge (P<0.05). The insulin response to glucose was significantly higher in rats treated with SIR compared with TAC (P<0.05). TAC, SIR and TAC-SIR treatments reduced number of estrus cycles (P<0.05). The ovaries were smaller after SIR and TAC-SIR treatment compared with controls. The TAC and TAC-SIR treatment groups had fewer preovulatory follicles. Corpora lutea were present in all groups. Ovarian aromatase expression was reduced in the SIR and TAC-SIR treatment groups. A significant (P<0.05) reduction in uterine size was observed in all treatment groups when compared with controls.

CONCLUSION

In a model of immunosuppressant-induced hyperglycemia, both TAC and SIR induced reproductive abnormalities in adult female rats, likely through different mechanisms.

Pre-transplant weight but not weight gain is associated with new-onset diabetes after transplantation: a multi-centre cohort Spanish study

Background. New-onset diabetes after transplantation (NODAT) is associated with poorer outcomes in kidney transplantation (KT). Thus, identification of modifiable risk factors may be crucial for ameliorating the impact of this entity on transplant outcomes. We assessed the relationships between the weight, body mass index (BMI) and weight gain with NODAT.Methods. We retrospectively analysed 2168 KT performed in Spain during 1990, 1994, 1998 and 2002, with a functioning graft after the first year. At 1 year after KT, three groups were considered: (i) NODAT group (n = 215); (ii) impaired fasting glucose (IFG) group (n = 389); (iii) control group (n = 1564).Results. The incidence of NODAT was 10.8%, 9.9% and 10.0% at 3, 12 and 24 months post-transplantation, respectively. Older recipient age (P < 0.0001) and greater use of tacrolimus (P < 0.0001) were observed in NODAT group. Obesity was more frequent in NODAT group (P < 0.0001), but patients with NODAT had a lower weight gain during the first year after KT (P = 0.038). On multivariate analysis, independent risk factors associated with the development of NODAT were: recipient age [odds ratio (OR): 1.060, P = 0.0001], tacrolimus (OR: 1.611, P = 0.005), triglycerides (OR: 1.511, P = 0.018), positive hepatitis C virus (HCV) status (OR: 1.969, P = 0.001) and pre-transplant body mass index (BMI) (OR: 1.135, P = 0.0001), but not the weight gain.Conclusions. BMI, but not the weight gain at 1 year after transplant, is an independent risk factor for NODAT. Tailoring clinical strategies may minimize the impact of this complication.

Hyperglycemia induced by tacrolimus and sirolimus is reversible in normal sprague-dawley rats

Post-transplant diabetes mellitus (PTDM) worsens outcomes after kidney transplantation, and immunosuppression agents contribute to PTDM. We have previously shown that tacrolimus (TAC) and sirolimus (SIR) cause hyperglycemia in normal rats. While there is little data on the mechanism for immunosuppressant-induced hyperglycemia, we hypothesized that the TAC and SIR-induced changes are reversible. To study this possibility, we compared normal rats treated for 2 weeks with either TAC, SIR, or a combination of TAC and SIR prior to evaluating their response to glucose challenge, with parallel groups also treated for 2 weeks after which treatment was stopped for 4 weeks, prior to studying their response to glucose challenge. Mean daily glucose and growth velocity was decreased in SIR, and TAC+SIR-treated animals compared to controls (P < 0.05). TAC, SIR, and TAC+SIR treatment also resulted in increased glucose response to glucose challenge, compared to controls (P < 0.05). SIR-treated animals also had elevated insulin concentrations in response to glucose challenge, compared to controls (P < 0.05). Insulin content was decreased in TAC and TAC+SIR, and islet apoptosis was also increased after TAC+SIR treatment (P < 0.05). Four weeks after treatments were stopped, all differences resolved between groups. In conclusion, TAC, SIR, and the combination of TAC+SIR-induced changes in glucose and insulin responses to glucose challenge that were accompanied by changes in islet apoptosis and insulin content. These changes were no longer present 4 weeks after cessation of therapy suggesting immunosuppressant-induced changes in glucose metabolism are likely reversible.

Incidence of and risk factors for posttransplant diabetes mellitus after pancreas transplantation

Posttransplant diabetes mellitus (PTDM) after pancreas transplantation (PTX) has not been extensively examined. This single center, retrospective analysis of 674 recipients from 1994 to 2005 examines the incidence of and risk factors for PTDM after PTX. PTDM was defined by fasting plasma glucose level > or =126 mg/dL, confirmed on a subsequent measurement or treatment with insulin or oral hypoglycemic agent for > or =30 days. The incidence of PTDM was 14%, 17% and 25% at 3, 5 and 10 years after PTX, respectively and was higher (p = 0.01) in solitary pancreas (PAN) versus simultaneous kidney pancreas (SPK) recipients (mean follow-up 6.5 years). In multivariate analysis, factors associated with PTDM were: older donor age (hazard ratio [HR] 1.04, 95% confidence interval [CI] 1.03-1.06, p < 0.001), higher recipient body mass index (HR 1.07,CI 1.01-1.13, p = 0.01), donor positive/recipient negative CMV status (HR 1.65,CI 1.03-2.6, p = 0.04), posttransplant weight gain (HR 4.7,CI 1.95-11.1, p < 0.001), pancreas rejection (HR 1.94.CI 1.3-2.9, p < 0.001) and 6 month fasting glucose (HR 1.01,CI 1.01-1.02, p < 0.001), hemoglobin A(1)c, (HR 1.12,CI 1.05-1.22, p = 0.002) and triglyceride to high-density lipoprotein (TG/HDL) ratio (HR 0.94,CI 0.91-0.96, p < 0.001). This study delineates the incidence and identifies risk factors for PTDM after PTX.

Posttransplantation hypomagnesemia and its relation with immunosuppression as predictors of new-onset diabetes after transplantation

New-onset diabetes after transplantation (NODAT) is a frequent complication and has an impact on patient and graft survival. Hypomagnesemia is common in both renal transplant recipients and in diabetics. This study examines the relationship between hypomagnesemia, NODAT and the type of immunosuppression in renal transplant recipients. We conducted a retrospective single-center analysis (2002-2008) in order to assess NODAT the first year posttransplantation as defined by American Diabetes Association criteria. Serum magnesium (Mg) levels were defined as the median of all Mg levels registered during the first month posttransplantation. Patients with NODAT (N = 75; 29.5%) versus non-NODAT had lower Mg levels (p < 0.001). Patients with an Mg level < versus > or = 1.9 mg/dL showed a faster development of NODAT (log-rank p < 0.001). Mg levels were lower in patients on calcineurin inhibitors (CNI) versus no CNI patients (p < 0.001). Mg levels, albumin, BMI, triglycerides, posttransplantation hyperglycemia, tacrolimus levels and the use of sirolimus were predictors of NODAT in the multivariate analysis. Hypomagnesemia was an independent predictor of NODAT in renal transplant recipients. We confirm that the use of CNI is associated with NODAT, but, to a large extent, this effect seems attributable to the induction of hypomagnesemia. After adjustment for Mg, sirolimus was also associated with NODAT.