Genetic polymorphisms of the transcription factor NFATc4 and development of new-onset diabetes after transplantation in Hispanic kidney transplant recipients. Transplantation. 2012;93:325-330. [PMID: 22234350 DOI: 10.1097/tp.0b013e31823f7f26]

[Risk factors for new-onset diabetes after transplantation in kidney transplant recipients: own data and meta-analysis]

AIM

To compare risk factors for new-onset diabetes after transplantation (NODAT) among renal transplant recipients (RTRs) from 1989 to 2018 in the City Clinical Hospital №52, with a systematic analysis of published studies on this topic.

MATERIALS AND METHODS

In a 30-year (1989-2018) retrospective study, we found statistically significant differences in age, gender, polycystic kidney disease, cadaveric kidney, cyclosporine, i-mTOR, and steroids between two groups of recipients with and without NODAT. Patients with NODAT were older, more male, more likely to have polycystic kidney disease and deceased donor kidneys, and more likely to be treated with cyclosporine, i-mTOR, and steroids (p<0.05). We conducted a meta-analysis to evaluate the impact of these indicators on the development of NODAT. MEDLINE, Scopus, and the Cochrane Central Register of Controlled Trials were searched for eligible case-control studies of risk factors for NODAT in RTRs published between 1990 and 2019. Meta-analysis of proportions was performed using the Freeman-Tukey transformation to calculate weighted summary proportions from a fixed and random effects model.

RESULTS

A total of 13 case-control studies were included in the meta-analysis. Of the total 849 studies found, 13 were included in the systematic review and meta-analysis, including ours, with a total of n=6797 RTRs, of which n=1305 patients with NODAT and n=5492 without NODAT. A wide range of data was recorded for the analysis of the incidence of NODAT (6.5-50.7%), with an average of 17.9% (fixed model) or 24.3% (random model). The proportion of NODAT recorded in the Russian registry of the City Clinical Hospital №52 was lower (11.5%), however, the data in the analyzed studies were highly heterogeneous: I2=98.14%, 95% CI: from 97.61 to 98.55, p<0.0001, Begg's test (p=0.05) and Egger's test (p=0.01) do not exclude the presence of publication bias in this case. Data on NODAT risk factors were less heterogeneous. This meta-analysis showed that age, polycystic kidney disease, i-mTOR and steroid therapy were associated with NODAT, whereas gender, calcineurin inhibitor use, and cadaveric kidney were not. There was no evidence of selection bias in any of the cases.

CONCLUSION

Risk factors for NODAT in kidney transplant recipients include older age, polycystic kidney disease, i-mTOR and steroid therapy, which initiate a state of insulin resistance. To reduce the risk of NODAT, the possibility of modifying immunosuppression regimens and the use of drugs that reduce insulin resistance and have a nephroprotective effect in RTRs should be considered. Therefore, randomized studies are needed to evaluate SGLT2 inhibitor in RTRs.

Diabetes Mellitus in Kidney Transplant Recipients: New Horizons in Treatment

Diabetes mellitus (DM) in kidney transplant recipients (KTR) is a risk factor for mortality, increases the risk of infections and, in the long term, can lead to graft loss due to diabetic kidney disease. A preventive approach applied to those on the waiting list could decrease the incidence of post-transplant DM (PTDM) by detecting those patients at risk, thus allowing strategies to minimize the probability of developing a New Onset Diabetes After Transplant (NODAT). On the other hand, modifications of immunosuppressive therapy may improve glucose control in patients with KTR. In recent years, two new classes of antidiabetic drugs and non-steroidal mineralocorticoid receptor antagonists have demonstrated cardiovascular and renal benefits in randomized clinical trials where the transplant population has not been represented. Because of the potential benefit expected in this population, the clinical use of glucagon-like peptide-1 receptor agonists (GLP-1RA), sodium-glucose cotransporter 2 inhibitors (SGLT2i) and finerenone is increasing in the kidney transplant setting. This review focuses on comprehensive pharmacological interventions in KTR with glucose metabolism disorders. In-depth knowledge in this area will allow prevention and identification of potential adverse effects or drug interactions in the clinical course of KTR with DM.

Genetic and Epigenetic Associations with Post-Transplant Diabetes Mellitus

Post-transplant diabetes mellitus (PTDM) is a common complication of solid organ transplantation. PTDM prevalence varies due to different diabetes definitions. Consensus guidelines for the diagnosis of PTDM have been published based on random blood glucose levels, glycated hemoglobin (HbA1c), and oral glucose tolerance test (OGTT). The task of diagnosing PTDM continues to pose challenges, given the potential for diabetes to manifest at different time points after transplantation, thus demanding constant clinical vigilance and repeated testing. Interpreting HbA1c levels can be challenging after renal transplantation. Pre-transplant risk factors for PTDM include obesity, sedentary lifestyle, family history of diabetes, ethnicity (e.g., African-Caribbean or South Asian ancestry), and genetic risk factors. Risk factors for PTDM include immunosuppressive drugs, weight gain, hepatitis C, and cytomegalovirus infection. There is also emerging evidence that genetic and epigenetic variation in the organ transplant recipient may influence the risk of developing PTDM. This review outlines many known risk factors for PTDM and details some of the pathways, genetic variants, and epigenetic features associated with PTDM. Improved understanding of established and emerging risk factors may help identify people at risk of developing PTDM and may reduce the risk of developing PTDM or improve the management of this complication of organ transplantation.

New-Onset Diabetes Mellitus after Kidney Transplantation

New-Onset Diabetes Mellitus after Transplantation (NODAT) emerges as a prevalent complication post-kidney transplantation, with its incidence influenced by variations in NODAT definitions and follow-up periods. The condition's pathophysiology is marked by impaired insulin sensitivity and β-cell dysfunction. Significant risk factors encompass age, gender, obesity, and genetics, among others, with the use of post-transplant immunosuppressants intensifying the condition. NODAT's significant impact on patient survival and graft durability underscores the need for its prevention, early detection, and treatment. This review addresses the complexities of managing NODAT, including the challenges posed by various immunosuppressive regimens crucial for transplant success yet harmful to glucose metabolism. It discusses management strategies involving adjustments in immunosuppressive protocols, lifestyle modifications, and pharmacological interventions to minimize diabetes risk while maintaining transplant longevity. The importance of early detection and proactive, personalized intervention strategies to modify NODAT's trajectory is also emphasized, advocating for a shift towards more anticipatory post-transplant care.

Genetic variations in a Sestrin2/Sestrin3/mTOR Axis and development of new-onset diabetes after kidney transplantation

BACKGROUND

Genetic variations in Sestrin2/Sestrin3/ mTOR axis may cause obesity-associated metabolic syndrome, including lipid accumulation and insulin resistance thereby increasing individual's risk of diabetes. In this study, we explored the association between single nucleotide polymorphisms (SNPs) of these genes and new onset diabetes after transplantation in Hispanic renal transplant recipients (RTRs).

METHODS

Nine potential functional polymorphisms in Sestrin2, Sestrin3 and mTOR genes were genotyped using the Taqman qPCR method in this study. We compared 160 Hispanic RTRs with no evidence of pre-existing diabetes, who developed new onset diabetes after transplantation (NODAT) with 152 controls with no history of diabetes. The logistic proportional hazard model was used to examine risks for NODAT. Nongenetic and genetic characteristics were included in the multivariate risk model.

RESULTS

Significant associations were observed between NODAT and mTOR TT (rs2295080 OR = 1.79, 95% CI =1.14-2.82, p = 0.01), Sestrin2 AA (rs580800, OR = 0.42, 95% CI =0.27-0.67, p = 0.002), and Sestrin3 AA (rs684856, OR = 0.45, 95% CI = 0.27-0.75, p = 0.001). Sestrin2 AA (rs580800), Sestrin3 AA (rs684856) and mTOR TT (rs2295080) remained significantly associated with NODAT after adjusting for acute rejection and sirolimus use. No interactions observed between the mTOR rs2295080 and Sestrin3 rs684856 and risk of NODAT (mTOR rs2295080 and Sestrin3 rs684856, p = 0.123 and mTOR rs2295080 and Sestrin2 rs580800, p = 0.167). Of the nongenetic factors, use of sirolimus and older age were associated with an increased risk for NODAT.

CONCLUSION

Polymorphisms in the Sestrin2/Sestrin3/ mTOR gene may confer certain protection/predisposition for NODAT.

Diabetes and Cardiovascular Risk in Renal Transplant Patients

End-stage kidney disease (ESKD) is a main public health problem, the prevalence of which is continuously increasing worldwide. Due to adverse effects of renal replacement therapies, kidney transplantation seems to be the optimal form of therapy with significantly improved survival, quality of life and diminished overall costs compared with dialysis. However, post-transplant patients frequently suffer from post-transplant diabetes mellitus (PTDM) which an important risk factor for cardiovascular and cardiovascular-related deaths after transplantation. The management of post-transplant diabetes resembles that of diabetes in the general population as it is based on strict glycemic control as well as screening and treatment of common complications. Lifestyle interventions accompanied by the tailoring of immunosuppressive regimen may be of key importance to mitigate PTDM-associated complications in kidney transplant patients. More transplant-specific approach can include the exchange of tacrolimus with an alternative immunosuppressant (cyclosporine or mammalian target of rapamycin (mTOR) inhibitor), the decrease or cessation of corticosteroid therapy and caution in the prescribing of diuretics since they are independently connected with post-transplant diabetes. Early identification of high-risk patients for cardiovascular diseases enables timely introduction of appropriate therapeutic strategy and results in higher survival rates for patients with a transplanted kidney.

Metabolic Consequences of Solid Organ Transplantation

Metabolic complications affect over 50% of solid organ transplant recipients. These include posttransplant diabetes, nonalcoholic fatty liver disease, dyslipidemia, and obesity. Preexisting metabolic disease is further exacerbated with immunosuppression and posttransplant weight gain. Patients transition from a state of cachexia induced by end-organ disease to a pro-anabolic state after transplant due to weight gain, sedentary lifestyle, and suboptimal dietary habits in the setting of immunosuppression. Specific immunosuppressants have different metabolic effects, although all the foundation/maintenance immunosuppressants (calcineurin inhibitors, mTOR inhibitors) increase the risk of metabolic disease. In this comprehensive review, we summarize the emerging knowledge of the molecular pathogenesis of these different metabolic complications, and the potential genetic contribution (recipient +/- donor) to these conditions. These metabolic complications impact both graft and patient survival, particularly increasing the risk of cardiovascular and cancer-associated mortality. The current evidence for prevention and therapeutic management of posttransplant metabolic conditions is provided while highlighting gaps for future avenues in translational research.

Risk factors for new-onset diabetes mellitus after kidney transplantation: A systematic review and meta-analysis

AIMS/INTRODUCTION

To systematically review the risk factors for new-onset diabetes mellitus after kidney transplantation, and to provide a theoretical basis for the prevention and management of new-onset diabetes mellitus after kidney transplantation.

MATERIALS AND METHODS

We searched PubMed, Web of Science, Embase, the Cochrane Library databases and other databases for case-control studies related to risk factors for new-onset diabetes mellitus after kidney transplantation published between January 2005 and July 2019. A meta-analysis of data on risk factors for new-onset diabetes mellitus after kidney transplantation from the included studies was carried out. A narrative review of risk factors for new-onset diabetes mellitus after kidney transplantation was also carried out.

RESULTS

A total of 24 case-control studies were included in the meta-analysis, with a total of 7,140 patients. There were 1,598 patients with new-onset diabetes mellitus after kidney transplantation, and 5,542 patients without new-onset diabetes mellitus after kidney transplantation. The meta-analysis results showed that age, polycystic kidney disease, family history of diabetes, body mass index, acute rejection, tacrolimus use, hepatitis B virus infection, hepatitis C virus infection and hypertension were associated with new-onset diabetes mellitus after kidney transplantation, whereas sex, sirolimus use, cyclosporin A use, steroid use and cytomegalovirus infection were not associated with new-onset diabetes mellitus after kidney transplantation.

CONCLUSIONS

Older age, body mass index, family history of diabetes, tacrolimus use, history of hypertension, polycystic kidney disease, acute rejection, hepatitis B virus infection and hepatitis C virus infection are risk factors for new-onset diabetes mellitus after kidney transplantation. Therefore, the clinical implications of these factors warrant attention.

FKBP-CaN-NFAT pathway polymorphisms selected by in silico biological function prediction are associated with tacrolimus efficacy in renal transplant patients

AIM

The aim of the present study was to investigate the potential effects of genetic variations in the FKBP-CaN-NFAT pathway on clinical events associated with tacrolimus efficacy in Chinese renal transplant patients.

METHODS

One hundred and forty Chinese renal transplant patients of Han ethnicity with over five years of follow-up were enrolled in our study. A pool of single nucleotide polymorphisms (SNPs) (1284 SNPs) was extracted from the Ensembl database according to chromosomal regions of the candidate genes. Next, 109 SNPs were screened out from this pool using multiple bioinformatics tools for subsequent genotyping using the MALDI-TOF-MS method. The associations of these candidate SNPs with acute rejection, nephrotoxicity, pneumonia and post-transplant estimated glomerular filtration rate (eGFR) were explored.

RESULTS

Fourty-four SNPs were found to be associated with tacrolimus-related clinical drug response. Specifically, eight SNPs were associated with the incidence of biopsy-proven acute rejection, four SNPs were associated with the rate of nephrotoxicity, 16 SNPs were correlated with the onset of pneumonia, and 26 SNPs were found to significantly influence post-transplant eGFR trend. An elaborate scoring system was implemented to prioritize the validation of these potentially causal SNPs. In particular, NFATC2 rs150348438 (G>T) performed well during integrative scoring (P_total=23.8) and was significantly associated with the occurrence of pneumonia (P = 0.0035, HR=0.91, 95% CI=0.85-0.97) and post-transplant eGFR levels (P = 0.000003).

CONCLUSIONS

NFATC2 rs150348438, rs6013219, rs1052653, and NFATC1 rs754093, ranking high in scoring, significantly affected the post-transplant eGFR and the incidence of pneumonia, acute rejection, and nephrotoxicity in renal transplant patients taking tacrolimus. Those SNPs may alter the expression and regulation of FKBP-CaN-NFAT pathway by influencing transcription regulation, mature mRNA degradation and RNA splicing, or protein coding. Critical SNPs of high ranking may serve as PD-associated pharmacogenetic biomarkers indicating individual response variability of TAC, and thus aid the clinical management of renal transplant patients.

Glyburide Regulates UCP1 Expression in Adipocytes Independent of KATP Channel Blockade

Identification of safe and effective compounds to increase or activate UCP1 expression in brown or white adipocytes remains a potent therapeutic strategy to combat obesity. Here we reported that, glyburide, one of the FDA-approved drugs currently used to treat type 2 diabetes, can significantly enhance UCP1 expression in both brown and white adipocytes. Glyburide-fed mice exhibited a clear resistance to high-fat diet-induced obesity, reduced blood triglyceride level, and increased UCP1 expression in brown adipose tissue. Moreover, in situ injection of glyburide to inguinal white adipose tissue remarkably enhanced UCP1 expression and increased thermogenesis. Further mechanistic studies indicated that the glyburide effect in UCP1 expression in adipocytes was KATP channel independent but may involve the regulation of the Ca2+-Calcineurin-NFAT signal pathway. Overall, our findings revealed the significant effects of glyburide in regulating UCP1 expression and thermogenesis in adipocytes, which can be potentially repurposed to treat obesity.

Post-Transplantation Diabetes Mellitus

Solid organ transplantation (SOT) is an established therapeutic option for chronic disease resulting from end-stage organ dysfunction. Long-term use of immunosuppression is associated with post-transplantation diabetes mellitus (PTDM), placing patients at increased risk of infections, cardiovascular disease and mortality. The incidence rates for PTDM have varied from 10 to 40% between different studies. Diagnostic criteria have evolved over the years, as a greater understating of PTDM has been reached. There are differences in pathophysiology and clinical course of type 2 diabetes and PTDM. Hence, managing this condition can be a challenge for a diabetes physician, as there are several factors to consider when tailoring therapy for post-transplant patients to achieve better glycaemic as well as long-term transplant outcomes. This article is a detailed review of PTDM, examining the pathogenesis, diagnostic criteria and management in light of the current evidence. The therapeutic options are discussed in the context of their safety and potential drug-drug interactions with immunosuppressive agents.

Pre, peri and posttransplant diabetes mellitus

PURPOSE OF REVIEW

The leading cause of death in both chronic kidney disease (CKD) and renal transplant patients is cardiovascular events. Post-transplant diabetes mellitus (PTx-DM), which is a major cardiovascular risk factor, is a metabolic disorder that affects 5.5-60.2% of renal allograft recipients by 1-year posttransplant (PTx). PTx-DM has been associated with a negative impact on patient and graft outcomes and survival.

RECENT FINDINGS

Individuals who develop PTx-DM are usually prone to this condition prior to and/or after developing CKD. Genetic factors, obesity, inflammation, medications and CKD all are risk factors for PTx-diabetes mellitus. The path to development of disease continues PTx frequently augmented by the use of diabetogenic maintenance immunosuppressive and some nonimmunosuppressive medications. These risk factors are usually associated with an increase in insulin resistance, a decrease in insulin gene expression and/or β-cell dysfunction and apoptosis.

SUMMARY

Some new anti-diabetes mellitus medications may help to improve the overall outcome; however, there is a real need for developing a preventive strategy. Identifying and targeting PTx-DM risk factors may help to guide the development of an effective programme. This could include the adoption of nondiabetogenic immunosuppressive protocols for high-risk patients.

Regulator of Calcineurin 1 helps coordinate whole-body metabolism and thermogenesis

Increasing non-shivering thermogenesis (NST), which expends calories as heat rather than storing them as fat, is championed as an effective way to combat obesity and metabolic disease. Innate mechanisms constraining the capacity for NST present a fundamental limitation to this approach, yet are not well understood. Here, we provide evidence that Regulator of Calcineurin 1 (RCAN1), a feedback inhibitor of the calcium-activated protein phosphatase calcineurin (CN), acts to suppress two distinctly different mechanisms of non-shivering thermogenesis (NST): one involving the activation of UCP1 expression in white adipose tissue, the other mediated by sarcolipin (SLN) in skeletal muscle. UCP1 generates heat at the expense of reducing ATP production, whereas SLN increases ATP consumption to generate heat. Gene expression profiles demonstrate a high correlation between Rcan1 expression and metabolic syndrome. On an evolutionary timescale, in the context of limited food resources, systemic suppression of prolonged NST by RCAN1 might have been beneficial; however, in the face of caloric abundance, RCAN1-mediated suppression of these adaptive avenues of energy expenditure may now contribute to the growing epidemic of obesity.

FKBP1A rs6041749 polymorphism is associated with allograft function in renal transplant patients

AIM

To investigate the potential impact of single-nucleotide polymorphisms (SNPs) in the FK506-binding protein (FKBP)-calcineurin (CaN)-nuclear factor of activated T cells (NFAT) signaling pathway on the efficacy and safety of tacrolimus (TAC) in Chinese renal transplant patients.

METHODS

Seventy-seven tag SNPs were detected in 146 patients who were on TAC-based maintenance immunosuppression and who followed up for at least 2 years. The relationships of these polymorphisms with clinical outcomes such as acute rejection, acute nephrotoxicity, pneumonia, and estimated glomerular filtration rate (eGFR) were explored. For the FKBP1A rs6041749 polymorphism, which has a significant association with renal function over time, a preliminary functional analysis was performed using a dual-luciferase reporter gene system.

RESULTS

The patients with FKBP1A rs6041749 TT genotype had a more stable eGFR level than CC and CT carriers (P = 2.08 × 10^-8) during the 2 years following transplantation. Dual-luciferase reporter assay results showed that the rs6041749 C variant could enhance the relative luciferase activity compared with the T variant, which indicated that the rs6041749 C allele may increase the FKBP1A gene transcription. In addition, we did not find any association between these genetic variants and the risk of acute rejection, acute nephrotoxicity, and pneumonia in renal transplant patients receiving TAC-based immunosuppression.

CONCLUSIONS

FKBP1A rs6041749 C allele carriers are at higher risk for eGFR deterioration. The variant might serve as a biomarker to predict allograft function in renal transplant patients.

Polymorphisms of nucleotide factor of activated T cells cytoplasmic 2 and 4 and the risk of acute rejection following kidney transplantation

BACKGROUND

Acute rejection (AR) is a common complication of kidney transplantation. Nuclear factors of activated T cells (NFATs) are transcription factors involved in the activation of T lymphocytes, but their association with AR is unclear.

METHODS

This retrospective, case-control study included 200 renal transplant recipients who were divided into the AR group (n = 69) and stable group (n = 131). Their blood samples were collected, and DNA was extracted from the whole blood. High-throughput next-generation sequencing was used to identify single nucleotide polymorphisms (SNPs) of the NFATC2 and NFATC4 genes. The correlation of these SNPs with AR was determined by logistic analysis.

RESULTS

Seventy-one SNPs of the NFATC2 and NFATC4 genes were identified by the sequencing and Hardy-Weinberg equilibrium analyses. After adjusting for age, gender and immunosuppressive protocols, 27 SNPs were correlated with AR, of which the SNP rs2426295 of the NFATC2 gene showed a significant correlation with AR in the HET model (AA vs. AC: OR = 0.43, 95% CI = 0.19-0.98, P = 0.045), but no significant NFATC4 SNPs were identified.

CONCLUSIONS

Our study shows that the rs2426295 variant of the NFATC2 gene is significantly associated with the occurrence of AR following kidney transplantation. And patients with AA genotypes in rs2426295 are inclined to suffer from AR pathogenesis.

[Post-transplantation diabetes mellitus in kidney recipients]

Post-transplantation diabetes mellitus is defined as diabetes that is diagnosed in grafted patients. It affects 20 to 30 % of kidney transplant recipients, with a high incidence in the first year. The increasing age at transplantation and the rising incidence of obesity may increase its prevalence in the next years. Post-transplantation diabetes mellitus is associated with poor outcomes, such as mortality, cardiovascular events or graft dysfunction. Its occurrence is mainly related to immunosuppressive agents, affecting both insulin secretion and sensibility. Immunosuppressants may be iatrogenic, and as such, induce an early and transient diabetes. They may also precociously determine a permanent diabetes, acting here as a promoting factor in patients proned to the development of type 2 diabetes. Lastly, they may behave, far from transplantation, as an additional risk factor for type 2 diabetes. The screening, management and prognosis of these different subtypes of post-transplantation diabetes mellitus will be different.

Genetic factors in pathogenesis of diabetes mellitus after kidney transplantation

Posttransplant diabetes mellitus (PTDM) is one of the major metabolic complications after transplantation of solid organs including the kidney. This type of diabetes mellitus affects allograft survival, cardiovascular complications and overall patient survival. The modifiable risk factors that contribute to PTDM include obesity, some viral infections (eg, hepatitis C virus, cytomegalovirus) and especially immunosuppressive drugs including corticosteroids, tacrolimus, cyclosporine and sirolimus. Currently, predisposing genetic factors have been considered important in PTDM development. The commonly evaluated genetic determinants include genes encoding transcription factors, cytokines, chemokines, adipokines, ionic channels, glucose transporters, cytochrome P450 enzymes and other enzymes metabolizing drugs, drug transporters. Unfortunately, the results of studies are inconclusive and differ between populations. There is a need for large genome-wide association study to identify the genetic risk factors associated with PTDM development.

NFATC1 genotypes affect acute rejection and long-term graft function in cyclosporine-treated renal transplant recipients

AIM

To investigate the effects of SNPs in the cyclophilin A/calcineurin/nuclear factor of activated T-cells (NFATs) pathway genes (PPIA, PPP3CB, PPP3R1, NFATC1 and NFATC2) on cyclosporine (CsA) efficacy in renal transplant recipients.

MATERIALS & METHODS

Seventy-six tag SNPs were detected in 155 CsA-treated renal recipients with at least a 5-year follow-up. The associations of SNPs with acute rejection, nephrotoxicity, pneumonia and estimated glomerular filtration rate post transplant were explored.

RESULTS

NFATC1 rs3894049 GC was a risk factor for acute rejection compared with CC carriers (p = 0.0005). NFATC1 rs2280055 TT carriers had a more stable estimated glomerular filtration rate level than CC (p = 0.0004).

CONCLUSION

Detecting NFATC1 polymorphisms could help predict CsA efficacy in renal transplant patients.

Risk assessment and management of post-transplant diabetes mellitus

The success rate of organ transplantation has been increasing with advances in surgical and pharmacological techniques. However, the number of solid organ transplant recipients who require metabolic disease management is also growing. Post-transplant diabetes mellitus (PTDM) is a common complication after solid organ transplantation and is associated with risks of graft loss, cardiovascular morbidity, and mortality. Other risk factors for PTDM include older age, genetic background, obesity, hepatitis C virus infection, hypomagnesemia, and use of immunosuppressant agents (corticosteroids, calcineurin inhibitors, and mammalian target of rapamycin inhibitor). Management of PTDM should be started before the transplantation plan to properly screen high-risk patients. Even though PTDM management is similar to that of general type 2 diabetes, therapeutic approaches must be made with consideration of drug interactions between immunosuppressive agents, glucose-lowering medications, and graft rejection and function.

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.

New challenges and promises in solid organ transplantation pharmacogenetics: the genetic variability of proteins involved in the pharmacodynamics of immunosuppressive drugs

Interindividual variability in immunosuppressive drug responses might be partly explained by genetic variants in proteins involved in the immune response or associated with IS pharmacodynamics. On a general basis, the pharmacogenetics of drug target proteins is less known and understood than that of proteins involved in drug disposition pathways. The aim of this review is to facilitate research related to the pharmacodynamics of the main immunosuppressive drugs used in solid organ transplantation. We elaborated a quality of evidence grading system based on a literature review and identified 'highly recommended', 'recommended' or 'potential' candidates for further research. It is likely that a number of additional rare variants might further explain drug response phenotypes in transplantation, and particularly the most severe ones. The advent of next-generation sequencing will help to identify those variants.

A HuGE Review and Meta-Analyses of Genetic Associations in New Onset Diabetes after Kidney Transplantation

PURPOSE

New onset diabetes after transplantation (NODAT) is a serious complication following solid organ transplantation. There is a genetic contribution to NODAT and we have conducted comprehensive meta-analysis of available genetic data in kidney transplant populations.

METHODS

Relevant articles investigating the association between genetic markers and NODAT were identified by searching PubMed, Web of Science and Google Scholar. SNPs described in a minimum of three studies were included for analysis using a random effects model. The association between identified variants and NODAT was calculated at the per-study level to generate overall significance values and effect sizes.

RESULTS

Searching the literature returned 4,147 citations. Within the 36 eligible articles identified, 18 genetic variants from 12 genes were considered for analysis. Of these, three were significantly associated with NODAT by meta-analysis at the 5% level of significance; CDKAL1 rs10946398 p = 0.006 OR = 1.43, 95% CI = 1.11-1.85 (n = 696 individuals), KCNQ1 rs2237892 p = 0.007 OR = 1.43, 95% CI = 1.10-1.86 (n = 1,270 individuals), and TCF7L2 rs7903146 p = 0.01 OR = 1.41, 95% CI = 1.07-1.85 (n = 2,967 individuals).

CONCLUSION

Evaluating cumulative evidence for SNPs associated with NODAT in kidney transplant recipients has revealed three SNPs associated with NODAT. An adequately powered, dense genome-wide association study will provide more information using a carefully defined NODAT phenotype.

New-onset diabetes mellitus after kidney transplantation: Current status and future directions

A diagnosis of new-onset diabetes after transplantation (NODAT) carries with it a threat to the renal allograft, as well as the same short- and long-term implications of type 2 diabetes seen in the general population. NODAT usually occurs early after transplantation, and is usually diagnosed according to general population guidelines. Non-modifiable risk factors for NODAT include advancing age, African American, Hispanic, or South Asian ethnicity, genetic background, a positive family history for diabetes mellitus, polycystic kidney disease, and previously diagnosed glucose intolerance. Modifiable risk factors for NODAT include obesity and the metabolic syndrome, hepatitis C virus and cytomegalovirus infection, corticosteroids, calcineurin inhibitor drugs (especially tacrolimus), and sirolimus. NODAT affects graft and patient survival, and increases the incidence of post-transplant cardiovascular disease. The incidence and impact of NODAT can be minimized through pre- and post-transplant screening to identify patients at higher risk, including by oral glucose tolerance tests, as well as multi-disciplinary care, lifestyle modification, and the use of modified immunosuppressive regimens coupled with glucose-lowering therapies including oral hypoglycemic agents and insulin. Since NODAT is a major cause of post-transplant morbidity and mortality, measures to reduce its incidence and impact have the potential to greatly improve overall transplant success.

Single-nucleotide polymorphisms in P450 oxidoreductase and peroxisome proliferator-activated receptor-α are associated with the development of new-onset diabetes after transplantation in kidney transplant recipients treated with tacrolimus

BACKGROUND

New-onset diabetes after transplantation (NODAT) is an important complication after kidney transplantation. The etiology of the malady is multifactorial and includes both environmental and genetic factors. NODAT is a polygenic disease and many single-nucleotide polymorphisms could constitute potential risk factors. Peroxisome proliferator-activated receptor α (PPARα) and P450 oxidoreductase (POR) play a central role in the control of energy metabolism in humans. Some recent data highlighted a possible functional impact of two single-nucleotide polymorphisms in PPARα (rs4253728 G>A and rs4823613 A>G) and one coding variant in POR (rs1057868; POR*28; A503V) on the activity of their respective encoded proteins. In the present study, we assessed the association between these variants and the risk of developing NODAT after kidney transplantation.

METHODS

Development of NODAT was investigated in 101 renal transplant recipients receiving tacrolimus-based immunosuppressive therapy. Patients were genotyped for PPARα and POR. The incidence of NODAT was compared between different genotypes. Kaplan-Meier and Cox's proportional-hazard analysis were used to evaluate the association of NODAT with potential risk factors. Potential nongenetic risk factors were also considered.

RESULTS

The PPARα rs4253728A>G and POR*28 variant alleles were both independently associated with an increased risk for NODAT with respective odds ratios of 8.6 [95% confidence interval (CI)=1.4-54.2; P=0.02] and 8.1 (95% CI=1.1-58.3; P=0.04). Other risk predictors included sex and body weight.

CONCLUSION

This candidate-gene study shows that polymorphisms in PPARα and POR might predispose patients being treated with tacrolimus to the development of NODAT after kidney transplantation. Patient management after organ transplantation might benefit from genotype data.

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.

Pharmacogenetic considerations for optimizing tacrolimus dosing in liver and kidney transplant patients

The introduction of tacrolimus in clinical practice has improved patient survival after organ transplant. However, despite the long use of tacrolimus in clinical practice, the best way to use this agent is still a matter of intense debate. The start of the genomic era has generated new research areas, such as pharmacogenetics, which studies the variability of drug response in relation to the genetic factors involved in the processes responsible for the pharmacokinetics and/or the action mechanism of a drug in the body. This variability seems to be correlated with the presence of genetic polymorphisms. Genotyping is an attractive option especially for the initiation of the dosing of tacrolimus; also, unlike phenotypic tests, the genotype is a stable characteristic that needs to be determined only once for any given gene. However, prospective clinical studies must show that genotype determination before transplantation allows for better use of a given drug and improves the safety and clinical efficacy of that medication. At present, research has been able to reliably show that the CYP3A5 genotype, but not the CYP3A4 or ABCB1 ones, can modify the pharmacokinetics of tacrolimus. However, it has not been possible to incontrovertibly show that the corresponding changes in the pharmacokinetic profile are linked with different patient outcomes regarding tacrolimus efficacy and toxicity. For these reasons, pharmacogenetics and individualized medicine remain a fascinating area for further study and may ultimately become the face of future medical practice and drug dosing.

The incidence of posttransplantation diabetes mellitus during follow-up in kidney transplant recipients and relationship to Fok1 vitamin D receptor polymorphism

BACKGROUND

Posttransplantation diabetes mellitus (PTDM) is a common, serious complication of kidney transplantation. The purpose of this study was to investigate the incidence of and risk factors for PTDM in relationship to Fok1 vitamin D receptor (VDR) polymorphisms.

METHODS

One hundred five kidney transplant recipients with normal glucose values before transplantation were recruited for this study. All patients underwent fasting plasma glucose (FPG) determinations followed by oral glucose tolerance tests (OGTTs) among normal FPG recipients. Every recipient underwent Fok1 VDR polymorphism analysis using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP).

RESULTS

Among 105 recipients, 16 (15.24%) developed new-onset PTDM within 6 months after kidney transplantation. Compared with 89 non-PTDM recipients, the mean age was significantly higher among recipients with PTDM: 47.81 ± 15.54 vs 36.62 ± 11.43 years (P = .001). Patients treated with tacrolimus were more susceptible to PTDM (56.25% vs 28.09%; P = .027). The distribution frequencies of Fok1 genotypes in this cohort followed the Hardy-Weinberg equilibrium. The frequencies of 3 genotypes (FF/Ff/ff; P = .040) and 2 alleles (F/f; P = .009) differed between the 2 groups. Multivariate analysis by logistic regression showed age older than 40 years (odds ratio, 7.774; P = .005), VDR Fok1 f allele (odds ratio, 11.765; P = .012), and tacrolimus therapy (odds ratio, 7.499; P = .007) to be related to the development of PTDM.

CONCLUSIONS

The incidence of newly diagnosed PTDM in this study was 15.24%. Fok1 VDR polymorphism was a genetic marker predicting PTDM risk. Age older than 40 years and tacrolimus were independent risk factors for PTDM.

Preventing and managing hyperglycemia in kidney transplant patients

PURPOSE OF REVIEW

New onset diabetes after kidney transplantation (NODAT) remains a common complication after transplantation and is associated with significant morbidity and mortality. The review will examine recent advances in our knowledge of this metabolic disorder and speculate upon future development.

RECENT FINDINGS

Research continues to broaden the horizon of existing and emerging risk factors that contribute to development of NODAT. Attempts to use this knowledge to develop quantitative risk scoring composites have been made, utilizing either pretransplant or 1-year posttransplantation variables, with variable success. Reassuringly a number of clinical trials have been published, or are currently in progress, that utilize pharmacological intervention for both prevention and management of NODAT. These are both in the form of differential immunosuppressant regimens or use of antiglycemic agents. Upcoming results will prove crucial in developing a genuine evidence-base for NODAT management.

SUMMARY

Rather than simple translation of data from the general to kidney transplant population, clinicians must appreciate that NODAT constitutes a distinct metabolic entity with unique pathophysiology. As such targeted strategies to prevent and manage NODAT require focused investigation to deal with this common complication.

Post-renal transplant diabetes mellitus in korean subjects: superimposition of transplant-related immunosuppressant factors on genetic and type 2 diabetic risk factors

Postrenal transplantation diabetes mellitus (PTDM), or new-onset diabetes after organ transplantation, is an important chronic transplant-associated complication. Similar to type 2 diabetes, decreased insulin secretion and increased insulin resistance are important to the pathophysiologic mechanism behind the development of PTDM. However, β-cell dysfunction rather than insulin resistance seems to be a greater contributing factor in the development of PTDM. Increased age, family history of diabetes, ethnicity, genetic variation, obesity, and hepatitis C are partially accountable for an increased underlying risk of PTDM in renal allograft recipients. In addition, the use of and kinds of immunosuppressive agents are key transplant-associated risk factors. Recently, a number of genetic variants or polymorphisms susceptible to immunosuppressants have been reported to be associated with calcineurin inhibition-induced β-cell dysfunction. The identification of high risk factors of PTDM would help prevent PTDM and improve long-term patient outcomes by allowing for personalized immunosuppressant regimens and by managing cardiovascular risk factors.