Role of insulin resistance indices in predicting new-onset diabetes after kidney transplantation

Prediction of Early Kidney Transplant Graft Outcome: Insulin Resistance Index

BACKGROUND

New-onset diabetes after transplantation and increased insulin resistance have both been shown to affect graft performance and survival after kidney transplantation. Thus, we aimed to evaluate the predictive roles of different insulin resistance indices on early graft function in kidney transplant recipients.

MATERIALS AND METHODS

We conducted a retrospective analysis of non-diabetic patients who received kidney transplantation between January 1, 2018 and December 31, 2021. The primary outcome was the predictive role of different insulin resistance indices on early graft function of serum creatinine level and estimated glomerular filtration rate at 1, 3, 6, and 12 months. The secondary outcome analyzed was the possible clinical predictive factors for poor kidney graft function at 12 months.

RESULTS

Among 123 kidney transplantation patients, stratification with homeostatic model assessment for insulin resistance showed no significant difference in kidney graft function outcome at 1, 3, 6, and 12 months. However, patients with a higher insulin-to-glucose ratio exhibited a significantly higher serum creatinine level at 3 and 6 months and a significantly lower estimated glomerular filtration rate level at 3, 6, and 12 months. Using multivariate logistic regression analysis, patients with a higher insulin-to-glucose ratio were associated with a poorer kidney graft function 12 months after transplantation.

CONCLUSION

Patients with a higher baseline insulin resistance with an insulin-to-glucose ratio ≥of 0.092 exhibited a significantly worse early kidney graft function. Thus, with the identification of patients with increased insulin resistance, early intervention, and preventive measures can be implemented to enhance graft performance further.

Early post-transplant hyperglycemia and post-transplant diabetes mellitus following heart transplantation

INTRODUCTION

Heart transplantation is an important treatment for end-stage heart failure. Early post-transplant hyperglycemia (EPTH) and post-transplant diabetes mellitus (PTDM) are common following heart transplantation and are associated with increased morbidity and mortality.

AREAS COVERED

This review summarizes the clinical characteristics, diagnosis, and treatment of EPTH and PTDM in cardiac transplant patients, incorporating findings from non-cardiac solid organ transplant studies where relevant due to limited heart-specific research.

EXPERT OPINION

EPTH following heart transplantation is common yet understudied and is associated with the later development of PTDM. PTDM is associated with adverse outcomes including infection, renal dysfunction, microvascular disease, and an increased risk of re-transplantation and mortality. Risk factors for EPTH include the post-operative immunosuppression regimen, recipient and donor age, body mass index, infections, and chronic inflammation. Early insulin treatment is recommended for EPTH, whereas PTDM management is varied and includes lifestyle modification, anti-glycemic agents, and insulin. Given the emerging evidence on the transplant benefits associated with effective glucose control, and the cardioprotective potential of newer anti-glycemic agents, further focus on the management of EPTH and PTDM within heart transplant recipients is imperative.

Leptin receptor gene polymorphisms in kidney transplant patients with post-transplant diabetes mellitus treated with tacrolimus

Post-transplant diabetes mellitus (PTDM) is a metabolic complication that often occurs after kidney transplantation. Factors that increase the risk of this complication are currently being researched, including polymorphisms in genes affecting carbohydrate-lipid metabolism. Leptin is a hormone that affects appetite and adipose tissue and plays an important role in regulating insulin secretion as well as glucose and lipid metabolism. The aim of this study was to examine the association between leptin receptor gene polymorphisms and the development of post-transplant diabetes mellitus in patients treated with tacrolimus. The study was carried out in a group of 201 patients who underwent kidney transplantation. The follow-up period was 12 months. PTDM was diagnosed in 35 patients. Analysing the LEPR gene rs1137101 polymorphism, we observed in patients with PTDM an increased frequency of GG genotype carriers (GG vs AA, OR 3.36; 95 % CI 0.99-11.46; p = 0.04). There were no statistically significant differences in the distribution of the LEPR rs1137100 and LEPR rs1805094 polymorphisms between patients with and without PTDM. Multivariate regression analysis confirmed that female sex, advanced age, increased BMI and a higher number of LEPR rs1137101 G alleles were independent risk factors for PTDM development. The risk of PTDM development was almost 3.5 times greater in LEPR rs1137101 G allele carriers than in AA homozygotes (GG + AG vs AA; OR 3.48; 95 %CI (1.09-11.18), p = 0.035). The results suggest that patients after kidney transplantation with the LEPR gene rs1137101 G allele may have an increased risk of post-transplant diabetes development.

The effect of PINK1/Parkin pathway on glucose homeostasis imbalance induced by tacrolimus in mouse livers

Treatment using the immunosuppressive drug tacrolimus (TAC) is related to new-onset diabetes after transplantation (NODAT). Previous studies focused mainly on islet β cells in the diabetogenic effect of TAC. Herein, we revealed that NODAT was probably induced by TAC via hepatic insulin resistance. After daily injection of mice with TAC, a glucose metabolism disorder was induced. In addition, TAC decreased the mRNA and protein levels of insulin receptor substrate 2 (IRS2), glucose transporter type 2 (GLUT2), and the phosphorylation of protein kinase B beta (pAKT2), which indicated impaired hepatic insulin signaling. Furthermore, the PTEN-induced novel kinase 1(PINK1)/Parkin pathway was shown to have a key role in the TAC-induced imbalance of hepatic glucose homeostasis. Mechanistic investigations in human hepatic cell lines revealed that TAC stimulated PINK1/Parkin expression and inhibited the expression of insulin signaling related molecules (e.g., IRS2, GLUT2 and pAKT2). Knockdown of hepatic PINK1 regulated downstream molecules of the PINK1/Parkin pathway (GLUT2 and IRS2), which reversed TAC-induced insulin resistance. Thus, in the liver, PINK1/Parkin signaling plays an important role in the TAC-induced imbalance of glucose homeostasis. TAC-induced diabetes might be prevented using Targeted treatment.

Progress of new-onset diabetes after liver and kidney transplantation

Organ transplantation is currently the most effective treatment for end-stage organ failure. Post transplantation diabetes mellitus (PTDM) is a severe complication after organ transplantation that seriously affects the short-term and long-term survival of recipients. However, PTDM is often overlooked or poorly managed in its early stage. This article provides an overview of the incidence, and pathogenesis of and risk factors for PTDM, aiming to gain a deeper understanding of PTDM and improve the quality of life of recipients.

Analysis of risk factors and establishment of a risk prediction model for post-transplant diabetes mellitus after kidney transplantation

Introduction

Post-transplant diabetes mellitus (PTDM) is a known side effect in transplant recipients administered immunosuppressant drugs, such as tacrolimus. This study aimed to investigate the risk factors related to PTDM, and establish a risk prediction model for PTDM. In addition, we explored the effect of PTDM on the graft survival rate of kidney transplantation recipients.

Methods

Patients with pre-diabetes mellitus before kidney transplant were excluded, and 495 kidney transplant recipients were included in our study, who were assigned to the non-PTDM and PTDM groups. The cumulative incidence was calculated at 3 months, 6 months, 1 year, 2 years, and 3 years post-transplantation. Laboratory tests were performed and the tacrolimus concentration, clinical prognosis, and adverse reactions were analyzed. Furthermore, binary logistic regression analysis was used to identify the independent risk factors of PTDM.

Results

Age ≥ 45 years (adjusted odds ratio [aOR] 2.25, 95% confidence interval [CI] 1.14–3.92; P = 0.015), body mass index (BMI) > 25 kg/m² (aOR 3.12, 95% CI 2.29–5.43, P < 0.001), tacrolimus concentration > 10 ng/mL during the first 3 months post-transplantation (aOR 2.46, 95%CI 1.41–7.38; P < 0.001), transient hyperglycemia (aOR 4.53, 95% CI 1.86–8.03; P < 0.001), delayed graft function (DGF) (aOR 1.31, 95% CI 1.05–2.39; P = 0.019) and acute rejection (aOR 2.16, 95% CI 1.79–4.69; P = 0.005) were identified as independent risk factors of PTDM. The PTDM risk prediction model was developed by including the above six risk factors, and the area under the receiver operating characteristic curve was 0.916 (95% CI 0.862–0.954, P < 0.001). Furthermore, the cumulative graft survival rate was significantly higher in the non- PTDM group than in the PTDM group.

Conclusions

Risk factors related to PTDM were age ≥ 45 years, BMI > 25 kg/m², tacrolimus concentration > 10 ng/mL during the first 3 months post-transplantation, transient hyperglycemia, DGF and acute rejection.

Serum hs-CRP measured prior transplantation predicts of new-onset diabetes after transplantation in renal transplant recipients

BACKGROUND

To assess the incidence of new-onset diabetes after transplantation (NODAT) for the first year post-transplantation and the predictive value of high-sensitivity C-reactive Protein (hs-CRP) before transplantation for NODAT prediction in kidney transplantation patients.

MATERIAL AND METHODS

A study of 251 consecutive adult end-stage kidney disease patients transplanted kidneys from living donors, follow-up during the first year to find NODAT. We diagnosed NODAT based on blood glucose or HbA1c following to the criteria of the American Diabetes Association.

RESULTS

The ratio of NODAT was 12.4%. The mean age, mean BMI, the proportion of arteriosclerosis, and the median hs-CRP level in NODAT group were significantly higher than those of non-NODAT group with p < 0.05. Age, BMI and serum hs-CRP had a predictive value for NODAT (Age: AUC = 0.62, p < 0.05, BMI: AUC = 0.626, hs-CRP: AUC = 0.748, p < 0.001).

CONCLUSION

Serum hs-CRP level measured prior transplantation is a good predictor for NODAT in renal transplant recipients.

pre-existing diabetes and PTDM in kidney transplant recipients: how to handle immunosuppression

INTRODUCTION

Preexisting diabetes (PD) and post-transplant diabetes mellitus (PTDM) are common and severe comorbidities posttransplantation. The immunosuppressive regimens are modifiable risk factors.

AREAS COVERED

We reviewed Pubmed and Cochrane database and we summarize the mechanisms and impacts of available immunosuppressive treatments on the risk of PD and PTDM. We also assess the possible management of these drugs to improve glycemic parameters while considering risks inherent in transplantation.

EXPERT OPINION

PD i) increases the risk of sepsis, ii) is an independent risk factor for infection-related mortality, and iii) increases acute rejection risk. Regarding PTDM development i) immunosuppressive strategies without corticosteroids significantly reduce the risk but the price may be a higher incidence of rejection; ii) minimization or rapid withdrawal of steroids are two valuable approaches; iii) the diabetogenic role of calcineurin inhibitors(CNIs) is also well-described and is more important for tacrolimus than for cyclosporine. Reducing tacrolimus-exposure may improve glycemic parameters but also has a higher risk of rejection. PTDM risk is higher in patients that receive sirolimus compared to mycophenolate mofetil. Finally, conversion from CNIs to belatacept may offer the best benefits to PTDM-recipients in terms of glycemic parameters, graft and patient-outcomes.

Prediabetes and older age increase the risk of post-transplantation diabetes mellitus: Qatar experience

Post-transplantation diabetes mellitus (PTDM) is a major complication in kidney transplant recipients leading to reduced allograft and patient survival. Given the high prevalence of diabetes in Qatar, which is twice the global average, we were interested in determining the incidence of PTDM, identifying risk factors, and comparing clinical outcomes in kidney transplant recipients with and without diabetes. We retrospectively followed up 191 adult kidney allograft recipients transplanted between January 1, 2012, and December 31, 2016, for a median of 41 months. A total of 76 patients (40%) had pre-existing diabetes. A total of 39 patients developed PTDM during follow-up; they represent 34% of patients who did not have diabetes prior to transplantation. Two thirds of PTDM occurred within 3-6 months post-transplantation. Prediabetes before transplant [OR = 6.07 (1.24-29.74), P = .026] older recipient's age at the time of transplantation [OR = 1.10 (1.00-1.20), P = .039] and average fasting blood sugar during 3-6 months post-transplant [OR = 1.06 (1.01-1.11), P = .010] were independently associated with PTDM. Patient and kidney allograft survival rates exceeded 97% in all groups. The incidence of PTDM in kidney transplant recipients living in Qatar is high. Older age and prediabetes are independent risk factors for developing PTDM.

Association of body mass index and fasting plasma glucose concentration with post-transplantation diabetes mellitus in Chinese heart transplant recipients

Objective

Post-transplantation diabetes mellitus (PTDM) is a frequent complication after heart transplantation. We investigated the specific predictors of PTDM in Chinese heart transplant recipients and the prognostic value of these predictors.

Methods

We retrospectively analyzed 122 adult patients who underwent heart transplantation. Comparisons were made between patients with PTDM (n = 44) and those without PTDM (n = 78).

Results

During the median follow-up of 44 months, the cumulative incidence of PTDM was 19.7% at 1 year after transplantation and 36.1% at the endpoint. PTDM was associated with a significantly higher preoperative body mass index (BMI) (odds ratio [OR] = 1.349), fasting plasma glucose (FPG) concentration (OR = 2.538), and serum uric acid concentration (OR = 1.005) after transplantation. The area under the receiver operating characteristic curve was 0.708 and 0.763 for the BMI and FPG concentration, respectively. The incidence of acute rejection and infection were higher and the all-cause mortality rate was considerably greater in patients with than without PTDM.

Conclusions

A higher preoperative BMI (>23 kg/m²), FPG concentration (>5.2 mmol/L), and uric acid concentration could potentially predict PTDM in Chinese heart transplant recipients. PTDM influences long-term survival after heart transplantation.

The tacrolimus-induced glucose homeostasis imbalance in terms of the liver: From bench to bedside

Tacrolimus (TAC), the mainstay of maintenance immunosuppressive agents, plays a crucial role in new-onset diabetes after transplant (NODAT). Previous studies investigating the diabetogenic effects of TAC have focused on the β cells of islets. In this study, we found that TAC contributed to NODAT through directly affecting hepatic metabolic homeostasis. In mice, TAC-induced hypoglycemia rather than hyperglycemia during starvation via suppressing gluconeogenetic genes, suggesting the limitation of fasting blood glucose in the diagnosis of NODAT. In addition, TAC caused hepatic insulin resistance and triglyceride accumulation through insulin receptor substrate (IRS)2/AKT and sterol regulatory element binding protein (SREBP1) signaling, respectively. Furthermore, we found a pivotal role of CREB-regulated transcription coactivator 2 (CRTC2) in TAC-induced metabolic disorders. The restoration of hepatic CRTC2 alleviated the metabolic disorders through its downstream molecules (eg, PCK1, IRS2, and SREBP1). Consistent with the findings from bench, low CRTC2 expression in graft hepatocytes was an independent risk factor for NODAT (odds ratio = 2.692, P = .023, n = 135). Integrating grafts' CRTC2 score into the clinical model could significantly increase the predictive capacity (areas under the receiver operating characteristic curve: 0.71 vs 0.79, P = .048). Taken together, in addition to its impact on pancreatic cells, TAC induces "hematogenous diabetes" via CRTC2 signaling. Liver-targeted management may be of help to prevent or heal TAC-associated diabetes.

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.

Pretransplant Homeostasis Model Assessment of Insulin Resistance and Fasting Plasma Glucose Predict New-Onset Diabetes After Renal Transplant in Chinese Patients

BACKGROUND AND AIM

The present study aims to determine if homeostasis model assessment of insulin resistance (HOMA-IR) index, fasting plasma glucose (FPG), and plasma insulin (Ins) are able to predict development of new onset diabetes after transplant (NODAT) for kidney recipients.

METHODS

We performed a single-center retrospective study of 123 nondiabetic patients receiving a first renal transplant. The NODAT was diagnosed between 1 month and 1 year post transplant. Both univariate and multivariable analyses, including logistic regression analysis and Cox proportional hazards model, were applied to dissect potential pretransplant risk factors of NODAT.

RESULTS

A total of 26.8% (33/123) of recipients developed NODAT in the first year post transplant. The NODAT patients showed higher HOMA-IR index and increased levels of FPG and Ins than non-NODAT. Interestingly, we consistently revealed that both FPG (logistic: odds ratio [OR], 3.17 [1.41-6.45]; P = .01; Cox: OR, 2.75 [1.26-4.56]; P = .02) and HOMA-IR index (logistic: OR, 1.73 [1.21-2.87]; P = .02; Cox: OR, 1.72 [1.21-2.46]; P = .002) robustly predicted the development of NODAT. However, these analyses showed that neither plasma Ins nor hemoglobin A_1c was associated with NODAT.

CONCLUSION

Our findings suggest that pretransplant HOMA-IR and FPG are independent predictors for the development of NODAT in Chinese nondiabetic patients receiving a first renal transplant.

An observational Prospective Study to Evaluate the Preoperative Risk Factors of New-onset Diabetes Mellitus after Renal Transplantation in a Tertiary Care Centre in Eastern India

OBJECTIVES

This study aimed to determine the pre-transplant risk factors as independent predictors on the new-onset of diabetes mellitus after renal transplants (NODATs).

MATERIALS AND METHODS

A single-centred prospective real-world observational study of 100 subjects who underwent renal transplantation over a period of 2 years. All known patients with diabetes were excluded from the study. NODAT was defined according to the American Diabetes Association definition. In addition to pre-transplant workup 2 days prior to transplant, post-transplant follow-up done on weekly basis for 1^st month, every 15^th day from 1^st month to 3^rd month, monthly from 3^rd month to 12^th month. Each transplant patient followed up for 1 year post-transplant or for 6 months post-development of NODAT, whichever was later. All the pre-transplant variables namely body mass index (BMI), family history of diabetes mellitus (DM), HbA1c, fasting insulin level, fasting c-peptide level, serology for hepatitis B, C, serum magnesium level and pre-operative insulin ressistance were further compared between NODAT and non-NODAT groups at the end of the study to assess their strength of associations.

RESULTS

Among the 100 subjects included in the study, 24 developed NODAT. Risk factors namely age, family history of DM, BMI, hepatitis B and C infection, total cholesterol, triglyceride level, pre-operative HbA1c, pre-operative insulin resistance and pre-diabetes were significantly higher, whereas beta-cell function, ABO compatibility and magnesium levels being significantly lower in NODAT cohort.

CONCLUSION

The incidence of NODAT is quite high (24%). Risk of development of NODAT was related to traditional as well as novel risk factors. Key aspects lies in identifying patients at risk of developing NODAT, using traditional risk factors for early diagnosis and introducing interventions on modifiable risk factors for prevention and timely intervention.

Pretransplant HbA1c and Glucose Metabolism Parameters in Predicting Posttransplant Diabetes Mellitus and Their Course in the First 6 Months After Living-Donor Renal Transplant

OBJECTIVES

Posttransplant diabetes mellitus is a common and serious metabolic complication after renal transplant. Patients with uremia are known to have abnormal glucose metabolism characterized by insulin resistance and defects in insulin secretion, which are ameliorated to some extent with renal replacement therapy and more so with renal transplant. However, the diabetogenicity of calcineurin inhibitors compounds this state of dysglycemia and promotes the development of diabetes in some patients. It is not clear whether pretransplant dysglycemia is a risk factor for posttransplant diabetes mellitus and, if so, which between insulin resistance and pancreatic β-cell dysfunction is a major determinant in predicting posttransplant diabetes mellitus. Here, we examined the roles of the pretransplant oral glucose tolerance test, glycated hemoglobin (HbA1c) levels, and homeostatic model assessment-derived insulin resistance and beta-cell function in the prediction of posttransplant diabetes mellitus and the course of these indexes posttransplant. Our aim was to examine the correlations between these factors and their changes posttransplant with the development of posttransplant diabetes mellitus.

MATERIALS AND METHODS

Pretransplant fasting blood was drawn from patients for plasma glucose, insulin, C-peptide, and HbA1c levels, which was followed by a 2-hour oral glucose tolerance test. After transplant, patients were followed for 6 months to detect posttransplant diabetes mellitus. Serum insulin, C-peptide, and glycated hemoglobin levels were reexamined in patients with posttransplant diabetes mellitus at 1 and 6 months.

RESULTS

Twenty-one patients (29%) developed posttransplant diabetes mellitus. Pretransplant HbA1c was associated with development of posttransplant diabetes mellitus (odds ratio 27.04) on logistic regression. Homeostatic model assessment-derived insulin resistance improved significantly at 6 months posttransplant, whereas beta-cell function remained lower than pretransplant levels in patients with posttransplant diabetes mellitus.

CONCLUSIONS

Pretransplant HbA1c may be used as a predictive marker for posttransplant diabetes mellitus. Insulin resistance but not beta-cell function improves in patients with posttransplant diabetes mellitus at 6 months posttransplant.

Sirolimus induces depletion of intracellular calcium stores and mitochondrial dysfunction in pancreatic beta cells

Sirolimus (rapamycin) is an immunosuppressive drug used in transplantation. One of its major side effects is the increased risk of diabetes mellitus; however, the exact mechanisms underlying such association have not been elucidated. Here we show that sirolimus impairs glucose-stimulated insulin secretion both in human and murine pancreatic islets and in clonal β cells in a dose- and time-dependent manner. Importantly, we demonstrate that sirolimus markedly depletes calcium (Ca²⁺) content in the endoplasmic reticulum and significantly decreases glucose-stimulated mitochondrial Ca²⁺ uptake. Crucially, the reduced mitochondrial Ca²⁺ uptake is mirrored by a significant impairment in mitochondrial respiration. Taken together, our findings indicate that sirolimus causes depletion of intracellular Ca²⁺ stores and alters mitochondrial fitness, eventually leading to decreased insulin release. Our results provide a novel molecular mechanism underlying the increased incidence of diabetes mellitus in patients treated with this drug.

Diabetes Mellitus Following Renal Transplantation: Clinical and Pharmacological Considerations for the Elderly Patient

Post-transplant diabetes mellitus occurs in 30-50% of cases during the first year post-renal transplantation. It is associated with increased morbidity, mortality and healthcare costs. Risk factors include age and specific immunosuppression regimens. At the same time, renal transplantation is increasingly indicated in elderly (aged >65 years) patients as this proportion of older patients in the prevalent dialysis population has increased. The immune system and β cells undergo senescence and this impacts on the risk for developing post-transplant diabetes and our ability to prevent such development. It may, however, be possible to identify patients at risk of developing post-transplant diabetes, enabling treatment protocols that prevent or reduce the impact of post-transplant diabetes. Much work remains to be completed in this area and is facilitated by the growing base of knowledge regarding the pathophysiology of post-transplant diabetes. Should post-transplant diabetes develop, there are a range of treatment options available. There is increasing interest in using newer agents, although their safety and efficacy in transplant recipients remains to be conclusively established.

Incidence of Diabetes Mellitus After Kidney Transplantation in Slovakia: Multicentric, Prospective Analysis

BACKGROUND

The incidence rate of post-transplant diabetes mellitus (PTDM) after kidney transplantation (KT) is 5% to 40%. The objective of this analysis was to identify the risk factors of PTDM after KT in the Slovak Republic (SR).

METHODS

In the group of 133 patients/non-diabetics, we identified the risk factors of PTDM in the monitored period of 12 months from transplantation.

RESULTS

The incidence of PTDM in the SR in 2014 was 38.3%. By logistic regression, we discovered that the age at the time of KT [odds ratio, 1.0885; 95% CI, 1.0222-1.1592; P = .0082], the value of body mass index (BMI) at the time of KT [odds ratio, 1.4606; 95% CI, 1.0099-2.1125; P = .0442], and the value of insulin resistance index (homeostatic model assessment for insulin resistance) at the time of KT [odds ratio, 2.5183; 95% CI, 1.7119-3.4692; P < .0001] represented predictive factors of PTDM. The independent risk factors of PTDM in our group were age at the time of KT of more than 60 years [HR 0.3871; 95% CI 0.1659-1.7767; P = .0281], waist circumference at the time of KT in men more than 94 cm and in women more than 80 cm [HR, 3.4833; 95% CI, 1.2789-9.4878 (P = .0146)], BMI at the time of KT [HR 3.0011; 95% CI 1.0725-8.3977 (P = .0363)], and triacylglycerols at the time of KT more than 1.7 mmol/L [HR, 2.9763; 95% CI, 1.0141-8.7352; P = .0471].

CONCLUSIONS

In the group of Slovak patients after kidney transplantation, the dominating risk factor for PTDM development was insulin resistance prior to KT.

A Prospective Study of Renal Transplant Recipients: A Fall in Insulin Secretion Underpins Dysglycemia After Renal Transplantation

Background

Dysglycemia (encompassing impaired glucose tolerance and diabetes mellitus) arising after renal transplantation is common and confers a significant cardiovascular mortality risk. Nonetheless, the pathophysiology of posttransplant dysglycemia is not well described. The aim of this study was to prospectively and comprehensively assess glucose handling in renal transplant recipients from before to 12 months after transplantation to determine the underpinning pathophysiology.

Materials and Methods

Intravenous and oral glucose tolerance testing was conducted before and at 3 and 12 months posttransplantation. An intravenous glucose tolerance test was also performed on day 7 posttransplantation. We followed up 16 transplant recipients for 3 months and 14 recipients for 12 months. Insulin secretion, resistance and a disposition index (DI (IV)), a measure of β cell responsiveness in the context of prevailing insulin resistance, were also determined.

Results

At 12 months, 50% of renal transplant recipients had dysglycemia. Dysglycemia was associated with a dramatic fall in DI (IV) and this loss in β cell function was evident as early as 3 months posttransplantation (23.5 pretransplant; 6.4 at 3 months and 12.2 at 12 months posttransplant). Differences in the β cell response to oral glucose challenge were evident pretransplant in those destined to develop dysglycemia posttransplant (2-hour blood glucose level 5.6 mmol/L versus 6.8 mmol/L; P < 0.01).

Conclusions

Dysglycemia after renal transplantation is common, and the loss of insulin secretion is a major contributor. Subclinical differences in glucose handling are evident pretransplant in those destined to develop dysglycemia potentially heralding a susceptible β cell which under the stressors associated with transplantation fails.

The Origin of New-Onset Diabetes After Liver Transplantation: Liver, Islets, or Gut?

New-onset diabetes is a frequent complication after solid organ transplantation. Although a number of common factors are associated with the disease, including recipient age, body mass index, hepatitis C infection, and use of immunosuppressive drugs, new-onset diabetes after liver transplantation (NODALT) has the following unique aspects and thus needs to be considered its own entity. First, a liver graft becomes the patient's primary metabolic regulator after liver transplantation, but this would not be the case for kidney or other grafts. The metabolic states, as well as the genetics of the graft, play crucial roles in the development of NODALT. Second, dysfunction of the islets of Langerhans is common in cirrhotic patients and would be exacerbated by immunosuppressive agents, particularly calcineurin inhibitors. On the other hand, minimized immunosuppressive protocols have been widely advocated in liver transplantation because of liver tolerance (immune privilege). Third and last, through the "gut-liver axis," graft function is closely linked to gut microbiota, which is now considered an important metabolic organ and known to independently influence the host's metabolic homeostasis. Liver transplant recipients present with specific gut microbiota that may be prone to trigger metabolic disorders. In this review, we proposed 3 possible sites for the origin of NODALT, which are liver, islets, and gut, to help elucidate the underlying mechanism of NODALT.

mTOR Inhibition: Reduced Insulin Secretion and Sensitivity in a Rat Model of Metabolic Syndrome

BACKGROUND

Sirolimus (SRL) has been associated with new-onset diabetes mellitus after transplantation. The aim was to determine the effect of SRL on development of insulin resistance and β -cell toxicity.

METHODS

Lean Zucker rat (LZR) and obese Zucker rat (OZR) were distributed into groups: vehicle and SRL (0.25, 0.5, or 1.0 mg/kg) during 12 or 28 days. Intraperitoneal glucose tolerance test (IPGTT) was evaluated at days 0, 12, 28, and 45. Islet morphometry, β-cell proliferation, and apoptosis were analyzed at 12 days. Islets were isolated to analyze insulin content, insulin secretion, and gene expression.

RESULTS

After 12 days, SRL treatment only impaired IPGTT in a dose-dependent manner in OZR. Treatment prolongation induced increase of area under the curve of IPGTT in LZR and OZR; however, in contrast to OZR, LZR normalized glucose levels after 2 hours. The SRL reduced pancreas weight and islet proliferation in LZR and OZR as well as insulin content. Insulin secretion was only affected in OZR. Islets from OZR + SRL rats presented a downregulation of Neurod1, Pax4, and Ins2 gene. Genes related with insulin secretion remained unchanged or upregulated.

CONCLUSIONS

In conditions that require adaptive β -cell proliferation, SRL might reveal harmful effects by blocking β -cell proliferation, insulin production and secretion. These effects disappeared when removing the therapy.

CCL2 gene polymorphism is associated with post-transplant diabetes mellitus

Post-transplant diabetes mellitus (PTDM) is a common complication after solid organ transplantation, especially in recipients treated with calcineurin inhibitors. Previous studies suggest that chronic inflammation and chemokines play an important role in the pathogenesis of diabetes. Single-nucleotide polymorphisms (SNPs) can increase or decrease transcriptional activity and can change the production of chemokines. The aim of this study was to examine the association between CCL2 and CCL5 gene polymorphisms and the development of post-transplant diabetes mellitus. The study included 315 patients who received kidney transplants and were treated with calcineurin inhibitors. Patients were divided into two subgroups: with PTDM (n=43) and without PTDM (n=272). An additive model of univariate Cox regression analysis showed that the hazard of PTDM development was significantly positively associated with the number of CCL2 rs1024611 G alleles (HR 1.65; 95%CI 1.08-2.53; p=0.021). Multivariate Cox regression analysis, taking into the account the recipient's sex, age and BMI, as well as the number of G alleles of the CCL2 rs1024611 polymorphism, revealed that this polymorphism is an independent risk factor for post-transplant diabetes. The results of our study suggest an association between the CCL2 gene rs1024611 G allele and PTDM in patients treated with tacrolimus or cyclosporine.

Dysglycemia after renal transplantation: Definition, pathogenesis, outcomes and implications for management

New-onset diabetes after transplantation (NODAT) is major complication following renal transplantation. It commonly develops within 3-6 mo post-transplantation. The development of NODAT is associated with significant increase in risk of major cardiovascular events and cardiovascular death. Other dysglycemic states, such as impaired glucose tolerance are also associated with increasing risk of cardiovascular events. The pathogenesis of these dysglycemic states is complex. Older recipient age is a consistent major risk factor and the impact of calcineurin inhibitors and glucocorticoids has been well described. Glucocorticoids likely cause insulin resistance and calcineurin inhibitors likely cause β-cell toxicity. The impact of transplantation in incretin hormones remains to be clarified. The oral glucose tolerance test remains the best diagnostic test but other tests may be validated as screening tests. Possibly, NODAT can be prevented by administering insulin early in patients identified as high risk for NODAT. Once NODAT has been diagnosed altering immunosuppression may be acceptable, but creates the difficulty of balancing immunological with metabolic risk. With regard to hypoglycemic use, metformin may be the best option. Further research is needed to better understand the pathogenesis, identify high risk patients and to improve management options given the significant increased risk of major cardiovascular events and death.

Adiponectin and leptin gene polymorphisms in patients with post-transplant diabetes mellitus

Background: Post-transplant diabetes mellitus (PTDM) is a common metabolic complication after organ transplantation and may be associated with the use of calcineurin inhibitors (tacrolimus and cyclosporine). Leptin and adiponectin are adipokines and play an important role in the regulation of insulin secretion as well as glucose and lipid metabolism. Aim: The aim of this study was to examine the association between adiponectin and leptin gene polymorphisms and development of PTDM. Materials & methods: The study included 323 patients who received kidney transplants and were treated with calcineurin inhibitors (tacrolimus or cyclosporine). Results: The association between adiponectin and leptin gene polymorphisms and PTDM was studied in three models of Cox regression analysis – additive, dominant and recessive. In these three models, the LEP rs2167270 gene polymorphism was statistically significantly associated with increased risk of PTDM. The association between the LEP rs2167270 polymorphism and PTDM was confirmed by multivariate regression analysis. Conclusion: The results of our study suggest an association between the leptin rs2167270 gene A allele and PTDM.

Original submitted 27 February 2015; Revision submitted 22 May 2015

New onset diabetes after transplantation: Not another acronym!

New onset diabetes after transplantation is the onset of diabetes in previously non-diabetic individuals extending beyond the first month post-transplantation.

Insulin resistance as a risk factor for new-onset diabetes after kidney transplantation

INTRODUCTION

New-onset diabetes after transplantation (NODAT) is a serious and common complication after kidney transplantation. Insulin resistance, together with β-cell dysfunction, plays an essential role in the development of diabetes. Homeostasis model assessment of insulin resistance (HOMA-IR), which is calculated as [fasting plasma glucose (mmol/L) × fasting insulin (mU/L)]/22.5, is widely used as an index of insulin resistance. However, the correlation between pretransplant HOMA-IR and the development of NODAT has not been fully established.

METHODS

We performed a retrospective study of 44 nondiabetic patients who underwent living donor kidney transplantation in our hospital from July 2006 to October 2009. We compared the HOMA-IR and demographic variables of patients who developed NODAT with those who did not.

RESULTS

Five patients (11.4%) developed NODAT within 3 years after transplantation. There were no differences in demographic variables between patients who developed NODAT and those who did not. Logistic regression analysis revealed that HOMA-IR was a predictive factor of NODAT (odds ratio, 2.88; 95% CI, 1.11-9.59; P < .05).

CONCLUSIONS

Our results indicate that high HOMA-IR might be an important predictive factor for NODAT. These findings underline the importance of routine pretransplant measurements of fasting plasma glucose and serum insulin for evaluating HOMA-IR.

Genetics of new-onset diabetes after transplantation

New-onset diabetes after transplantation is a common complication that reduces recipient survival. Research in renal transplant recipients has suggested that pancreatic β-cell dysfunction, as opposed to insulin resistance, may be the key pathologic process. In this study, clinical and genetic factors associated with new-onset diabetes after transplantation were identified in a white population. A joint analysis approach, with an initial genome-wide association study in a subset of cases followed by de novo genotyping in the complete case cohort, was implemented to identify single-nucleotide polymorphisms (SNPs) associated with the development of new-onset diabetes after transplantation. Clinical variables associated with the development of diabetes after renal transplantation included older recipient age, female sex, and percentage weight gain within 12 months of transplantation. The genome-wide association study identified 26 SNPs associated with new-onset diabetes after transplantation; this association was validated for eight SNPs (rs10484821, rs7533125, rs2861484, rs11580170, rs2020902, rs1836882, rs198372, and rs4394754) by de novo genotyping. These associations remained significant after multivariate adjustment for clinical variables. Seven of these SNPs are associated with genes implicated in β-cell apoptosis. These results corroborate recent clinical evidence implicating β-cell dysfunction in the pathophysiology of new-onset diabetes after transplantation and support the pursuit of therapeutic strategies to protect β cells in the post-transplant period.

New onset of diabetes after transplantation - an overview of epidemiology, mechanism of development and diagnosis

New onset of diabetes after transplantation (NODAT) is a serious and common complication following solid organ transplantation. NODAT has been reported to occur in 2% to 53% of renal transplant recipients. Several risk factors are associated with NODAT, however the mechanisms underlying were unclear. Renal transplant recipients who develop NODAT are reported to be at increased risk of infections, cardiovascular events, graft loss and patient loss. It has been reported that the incidence of NODAT is high in the early transplant period due to the exposure to the high doses of corticosteroids, calcineurin inhibitors and the physical inactivity during that period. In addition to these risk factors the traditional risk factors also play a major role in developing NODAT. Early detection is crucial in the management and control of NODAT which can be achieved through pretransplant screening there by identifying high risk patients and implementing the measures to reduce the development of NODAT. In the present article we reviewed the literature on the epidemiology, risk factors, mechanisms involved and the diagnostic criteria in the development of NODAT. Development of diagnostic tools for the assessment of β-cell function and determination of the role of glycemic control would include future area of research.

Conversion to sirolimus therapy in kidney transplant recipients with new onset diabetes mellitus after transplantation

New-onset diabetes mellitus after transplantation (NODAT) may complicate 2–50% of kidney transplantation, and it is associated with reduced graft and patient survivals. In this retrospective study, we applied a conversion protocol to sirolimus in a cohort of kidney transplant recipients with NODAT. Among 344 kidney transplant recipients, 29 patients developed a NODAT (6.6%) and continued with a reduced dose of calcineurin inhibitors (CNI) (8 patients, Group A) or were converted to sirolimus (SIR) (21 patients, Group B). NODAT resolved in 37.5% and in 80% patients in Group A and Group B, respectively. In Group A, patient and graft survivals were 100% and 75%, respectively, not significantly different from Group B (83.4% and 68%, resp., P = 0.847). Graft function improved after conversion to sirolimus therapy: serum creatinine was 1.8 ± 0.7 mg/dL at the time of conversion and 1.6 ± 0.4 mg/dL five years after conversion to sirolimus therapy (P < 0.05), while in the group of patients remaining with a reduced dose of CNI, serum creatinine was 1.7 ± 0.6 mg/dL at the time of conversion and 1.65 ± 0.6 mg/dL at five-year followup (P = 0.732). This study demonstrated that the conversion from CNI to SIR in patients could improve significantly the metabolic parameters of patients with NODAT, without increasing the risk of acute graft rejection.

Novel views on new-onset diabetes after transplantation: development, prevention and treatment

New-onset diabetes after transplantation (NODAT) is associated with increased risk of allograft failure, cardiovascular disease and mortality, and therefore, jeopardizes the success of renal transplantation. Increased awareness of NODAT and the prediabetic states (impaired fasting glucose and impaired glucose tolerance, IGT) has fostered previous and present recommendations, based on the management of type 2 diabetes mellitus (T2DM). Unfortunately, the idea that NODAT merely resembles T2DM is potentially misleading, because the opportunity to initiate adequate anti-hyperglycaemic treatment early after transplantation might be given away for 'tailored' immunosuppression in patients who have developed NODAT or carry personal risk factors. Risk factor-independent mechanisms, however, seem to render postoperative hyperglycaemia with subsequent development of overt or 'full-blown' NODAT, the unavoidable consequence of the transplant and immunosuppressive process itself, at least in many cases. A proof of the concept that timely preventive intervention with exogenous insulin against post-transplant hyperglycaemia may decrease NODAT was recently provided by a small clinical trial, which is awaiting confirmation from a multicentre study. However, because early insulin therapy aimed at beta-cell protection seems to contrast the currently recommended, stepwise approach of 'watchful waiting' prior to pancreatic decompensation, we here aim at reviewing recent concepts regarding the development, prevention and treatment of NODAT, some of which seem to challenge the traditional view on T2DM and NODAT. In summary, we suggest a novel, risk factor-independent management approach to NODAT, which includes glycaemic monitoring and anti-hyperglycaemic treatment in virtually everybody after transplantation. This approach has widespread implications for future research and is intended to tackle NODAT and also ultimately cardiovascular disease.