Tacrolimus Induces Insulin Resistance and Increases the Glucose Absorption in the Jejunum: A Potential Mechanism of the Diabetogenic Effects

Tacrolimus induces insulin receptor substrate 1 hyperphosphorylation and inhibits mTORc1/S6K1 cascade in HL7702 cells

BACKGROUND

Tacrolimus (FK506) is a key calcineurin inhibitor used to prevent organ transplant rejection and is effective in improving graft survival. However, it is linked to hyperglycemia and insulin resistance, contributing to new-onset diabetes after transplantation and negatively affecting islet function.

AIM

To study the effects of tacrolimus on the insulin signaling pathway of hepatocytes.

METHODS

HL7702 cells were treated with different concentrations of tacrolimus (0.1 mg/L, 1 mg/L, 5 mg/L) for 24 hours. The proteins involved in insulin signaling were detected by Western blotting.

RESULTS

Compared with the control group, phosphorylation of insulin receptor substrate (IRS) 1 at Ser 307 and Ser 323 were increased significantly when the tacrolimus concentration reached 1 and 5 mg/L. Phosphorylation of IRS1 at Ser 1101 was also increased, although not significantly. However, phosphorylation of Ribosomal protein S6 kinase beta-1 at Thr 389 was decreased significantly. The levels of phosphorylated glycogen synthase kinase 3α Ser 21 and Ser 9 were increased. Surprisingly, phosphorylation of glycogen synthase at Ser 641 was increased. There was no significant change in the activity of glycogen phosphorylase.

CONCLUSION

Tacrolimus has no direct effect on hepatic glucose metabolism, but inhibits IRS1-mediated insulin signaling. This may be one of the underlying mechanisms by which tacrolimus induces insulin resistance.

Novel Therapeutic Agents for Cardiometabolic Risk Mitigation in Heart Transplant Recipients

Heart transplant (HT) recipients experience high rates of cardiometabolic disease. Novel therapies targeting hyperlipidemia, diabetes, and obesity, including proprotein convertase subtilisin/kexin inhibitors (PCSK9i), sodium-glucose cotransporter-2 (SGLT2) inhibitors, and glucagon-like peptide-1 (GLP-1) agonists are increasingly used for cardiometabolic risk mitigation in the general population. However, limited data exist to support the use of these agents in patients who have undergone heart transplantation. Herein, we describe the mechanisms of action and emerging evidence supporting the use of novel pharmacologic agents in the post-HT setting for cardiometabolic risk mitigation and review evidence supporting their ability to modulate immune pathways associated with atherogenesis, epicardial adipose tissue (EAT), and coronary allograft vasculopathy (CAV).

Overweight Impacts Histological Disease Activity of De Novo Metabolic Dysfunction-Associated Steatotic Liver Disease After Liver Transplantation

BACKGROUND AND AIMS

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a leading indication for liver transplantation (LT), but also occurs after LT. The prevalence of de novo MASLD (dnMASLD) after LT, based on both surveillance (svLbx) and indication biopsies (indLbx), is unknown. Furthermore, the impact of the distinct cardiometabolic risk factors on histological disease activity has not been assessed. We aimed to evaluate the prevalence of dnMASLD and the association between the cardiometabolic risk factors and histological disease activity.

METHODS

We performed a retrospective single-center study in a LT cohort with indLbx and svLbx. Patients with NAFLD before LT were excluded.

RESULTS

We analyzed 249 patients who underwent either svLbx or indLbx. Forty-eight (19.2%) had either dnMASLD (n = 26/249, 10.4%) or metabolic dysfunction associated steatohepatitis (dnMASH) (n = 22/249, 8.8%). Although dnMASLD/dnMASH was more frequent in indLbx (35.1%, p < 0.01), still 16.5% of patients with svLbx had dnMASLD/dnMASH. While overweight (p < 0.01) and diabetes (p = 0.01) were more frequent in patients with dnMASH, only overweight was associated with histological disease activity in the multivariate analysis. No impact of dnMASLD on the overall survival was observed.

CONCLUSION

While dnMASLD is more frequent in patients with indLBX, it also occurs in 16.5% of patients without signs of graft dysfunction. Overweight has the strongest impact on histological disease activity and should be monitored carefully after LT.

The use of metabolomics and machine learning algorithms to predict post-transplant diabetes mellitus in renal transplant patients on Tacrolimus therapy

Background and aim

Tacrolimus (TAC) has significantly improved kidney graft survival following transplantation, though it is associated with adverse side effects. The most prevalent complication resulting from excessive TAC exposure is the onset of de novo diabetes mellitus (DM), a condition that can negatively impact both renal graft function and patient outcomes. De novo DM is linked to an increased risk of chronic transplant dysfunction, as well as cardiovascular morbidity and mortality. Although the underlying mechanisms remain unclear, emerging research in the field of omics shows promise. The aim of this study was to investigate the metabolomic profile of kidney transplant patients who developed de novo DM, in comparison to those who did not, following TAC exposure, using untargeted metabolomic analysis through ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) and machine learning algorithms.

Methods

A cohort of 34 kidney transplant patients on a Tacrolimus regimen for at least 6 months was enrolled in the study, with serum samples collected from each patient. Comprehensive profiling of serum metabolites was performed, enabling the classification of patients into de novo diabetes mellitus and non diabetes groups. The metabolomic analysis of serum was conducted using UHPLC-MS.

Results

Of the 34 patients, 16 were diagnosed with TAC-induced diabetes. A total of 334 metabolites were identified in the serum samples, of which 10 demonstrated a significant correlation with the de novo diabetes mellitus group. Most of these metabolites were linked to alterations in lipid metabolism.

Conclusion

The application of metabolomics in kidney transplant patients undergoing a Tacrolimus regimen is both feasible and effective in identifying metabolites associated with de novo diabetes mellitus. This approach may provide valuable insights into the metabolic alterations underlying TAC-induced diabetes.

Inhibition of Calcineurin with FK506 Reduces Tau Levels and Attenuates Synaptic Impairment Driven by Tau Oligomers in the Hippocampus of Male Mouse Models

Alzheimer's disease (AD) is the most common age-associated neurodegenerative disorder, characterized by progressive cognitive decline, memory impairment, and structural brain changes, primarily involving Aβ plaques and neurofibrillary tangles of hyperphosphorylated tau protein. Recent research highlights the significance of smaller Aβ and Tau oligomeric aggregates (AβO and TauO, respectively) in synaptic dysfunction and disease progression. Calcineurin (CaN), a key calcium/calmodulin-dependent player in regulating synaptic function in the central nervous system (CNS) is implicated in mediating detrimental effects of AβO on synapses and memory function in AD. This study aims to investigate the specific impact of CaN on both exogenous and endogenous TauO through the acute and chronic inhibition of CaN. We previously demonstrated the protective effect against AD of the immunosuppressant CaN inhibitor, FK506, but its influence on TauO remains unclear. In this study, we explored the short-term effects of acute CaN inhibition on TauO phosphorylation and TauO-induced memory deficits and synaptic dysfunction. Mice received FK506 post-TauO intracerebroventricular injection and TauO levels and phosphorylation were assessed, examining their impact on CaN and GSK-3β. The study investigated FK506 preventive/reversal effects on TauO-induced clustering of CaN and GSK-3β. Memory and synaptic function in TauO-injected mice were evaluated with/without FK506. Chronic FK506 treatment in 3xTgAD mice explored its influence on CaN, Aβ, and Tau levels. This study underscores the significant influence of CaN inhibition on TauO and associated AD pathology, suggesting therapeutic potential in targeting CaN for addressing various aspects of AD onset and progression. These findings provide valuable insights for potential interventions in AD, emphasizing the need for further exploration of CaN-targeted strategies.

A retrospective analysis of the safety of tacrolimus use and its optimal cut-off concentration during pregnancy in women with systemic lupus erythematosus: study from two Japanese tertiary referral centers

BACKGROUND

Tacrolimus is one of the major treatment options for systemic lupus erythematosus (SLE) and is considered to be a pregnancy-compatible medication. Since little is known about tacrolimus safety during pregnancy complicated by SLE, this study was designed.

METHODS

We included SLE pregnant patients who were followed up at two Japanese tertiary referral centers. We performed multivariate logistic regression analysis to assess each adverse pregnancy outcome (APO) risk. Moreover, we assessed the influence of tacrolimus on the APO ratio in pregnant patients with lupus nephritis, and the impact of combined tacrolimus-aspirin therapy on the APO ratio relative to patients exclusively administered tacrolimus.

RESULTS

Of the 124 pregnancies, 29 were exposed to tacrolimus. Multivariate analysis showed no statistical difference in APO ratio. (overall APO: adjusted odds ratio [aOR], 0.69; 95% confidence interval [CI], 0.23-2.03; p = 0.50; maternal APO: aOR, 1.17; 95% CI, 0.36-3.83; p = 0.80; neonatal APO: aOR, 1.10; 95% CI, 0.38-3.21; p = 0.86; PROMISSE APO: aOR, 0.50; 95% CI, 0.14-1.74; p = 0.27). Blood pressure and estimated glomerular filtration rate (eGFR) during pregnancy and after delivery did not differ between the two groups. Receiver operating characteristic (ROC) curve showed that tacrolimus concentration > 2.6 ng/ml was related to reduced preterm birth rate. (AUC = 0.85, 95% CI: 0.61-1.00, sensitivity: 93% and specificity: 75%). Regarding effect of tacrolimus on lupus nephritis during pregnancy, tacrolimus showed no increased risk of APO, blood pressure or eGFR during pregnancy and after delivery. (overall APO: OR, 1.00; 95% CI, 0.25-4.08; p = 0.98; maternal APO: OR 1.60, 95% CI, 0.39-6.64; p = 0.51; neonatal APO: OR, 0.71; 95% CI, 0.17-3.03; p = 0.65, PROMISSE APO: OR, 0.50; 95% CI, 0.08-3.22; p = 0.47). Tacrolimus-aspirin combination therapy showed a protective tendency against hypertensive disorders during pregnancy, preeclampsia and low birth weight.

CONCLUSIONS

Tacrolimus use during pregnancy with SLE and lupus nephritis showed no significant influence on APO, blood pressure, or renal function; therefore tacrolimus may be suitable for controlling lupus activity during pregnancy. In addition, when using tacrolimus during pregnancy, we should aim its trough concentration ≥ 2.6 ng/ml while paying careful attention to possible maternal side effects of tacrolimus.

TRIAL REGISTRATION

Retrospectively registered.

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.

Fibrotic plaques in heart transplanted patients and their association with insulin resistance syndrome and Lp(a)

BACKGROUND

Angiographic evidence of cardiac allograft vasculopathy (CAV_angio) is a major limiting factor to survival after heart transplantation (HTx). Prevention of CAV_angio is therefore most relevant. Whether modifiable risk factors could be targeted for the prevention of fibrotic plaques, that are common and related to CAV_angio, is not clear.

METHODS AND RESULTS

In a cohort of 74 consecutive HTx patients (median post-transplant interval 9.2 [4.1-15.5] years), we used the high resolution of optical coherence tomography (OCT) to quantify angulation parameters (maximal and mean arc) and plaque load (mean arc*relative plaque length) of fibrotic plaques. Mean arc was defined as the mean value of all angulation measurements per patient. We assessed the association between cardiovascular risk factors and OCT findings. Linear regression analysis showed a significant association of TG/HDL-c with mean fibrotic arc (12.7 [3.9-21.5], p = 0.006) and fibrotic plaque load (2298 [617-3979], p = 0.009) after adjustment for recipient age and sex. We used the median value of fibrotic plaque load to define high fibrotic plaque load. In binary logistic regression analysis, TG/HDL-c (odds ratio [OR] 1.81 with 95% CI [1.09-3.03], p = 0.02) and Lp(a) (OR 1.02 [1.00-1.05], p = 0.02) were associated with high fibrotic plaque load. Multivariable logistic regression analysis confirmed Lp(a) as significant predictor of high fibrotic plaque load (OR 1.03 [1.01-1.05], p = 0.02).

CONCLUSION

TG/HDL-c ratio, a surrogate of insulin resistance syndrome, and Lp(a) were significantly associated with fibrotic plaque in HTx patients. Insulin resistance syndrome and Lp(a) might therefore represent additional targets for CAV prevention.

Non-Immunologic Causes of Late Death-Censored Kidney Graft Failure: A Personalized Approach

Despite continuous advances in surgical and immunosuppressive protocols, the long-term survival of transplanted kidneys is still far from being satisfactory. Antibody-mediated rejection, recurrent autoimmune diseases, and death with functioning graft are the most frequent causes of late-kidney allograft failure. However, in addition to these complications, a number of other non-immunologic events may impair the function of transplanted kidneys and directly or indirectly lead to their failure. In this narrative review, we will list and discuss the most important nonimmune causes of late death-censored kidney graft failure, including quality of the donated kidney, adherence to prescriptions, drug toxicities, arterial hypertension, dyslipidemia, new onset diabetes mellitus, hyperuricemia, and lifestyle of the renal transplant recipient. For each of these risk factors, we will report the etiopathogenesis and the potential consequences on graft function, keeping in mind that in many cases, two or more risk factors may negatively interact together.

Cardiovascular Risk after Kidney Transplantation: Causes and Current Approaches to a Relevant Burden

Background. Cardiovascular disease is a frequent complication after kidney transplantation and represents the leading cause of mortality in this population. Material and Methods. We searched for the relevant articles in the National Institutes of Health library of medicine, transplant, cardiologic and nephrological journals. Results. The pathogenesis of cardiovascular disease in kidney transplant is multifactorial. Apart from non-modifiable risk factors, such as age, gender, genetic predisposition and ethnicity, several traditional and non-traditional modifiable risk factors contribute to its development. Traditional factors, such as diabetes, hypertension and dyslipidemia, may be present before and may worsen after transplantation. Immunosuppressants and impaired graft function may strongly influence the exacerbation of these comorbidities. However, in the last years, several studies showed that many other cardiovascular risk factors may be involved in kidney transplantation, including hyperuricemia, inflammation, low klotho and elevated Fibroblast Growth Factor 23 levels, deficient levels of vitamin D, vascular calcifications, anemia and poor physical activity and quality of life. Conclusions. The timely and effective treatment of time-honored and recently discovered modifiable risk factors represent the basis of the prevention of cardiovascular complications in kidney transplantation. Reduction of cardiovascular risk can improve the life expectancy, the quality of life and the allograft function and survival.

Treatment with broad-spectrum antibiotics upregulates Sglt1 and induces small intestinal villous hyperplasia in mice

Although extensive evidence indicates that the gut microbiota plays a crucial role in regulating glucose homeostasis, the exact regulatory mechanism remains unclear. This study aimed to investigate the effect of broad-spectrum antibiotics on the expression of glucose transporters, histomorphology of the small intestine, and glucose metabolism in mice. C57BL/6 mice were administered drinking water with or without a broad-spectrum antibiotic combination for 4 weeks. Thereafter, an oral glucose tolerance test was performed. Body weight, small intestine histopathology, mRNA levels of glucose transporters (SGLT1 and GLUT2) and intestinal transcription factors (CDX1 and CDX2) were evaluated. SGLT1 and CDX1 were upregulated in the small intestine upon antibiotic administration compared with that in the control group. The height and surface area of the jejunal villi were significantly higher upon antibiotic administration than in the control group. Fasting glucose levels were significantly higher upon antibiotic administration than in the control group. The present results indicate that treatment with broad-spectrum antibiotics upregulates SGLT1 and CDX1 and induces hyperplasia in the small intestine, thus increasing fasting blood glucose levels. Our results further the current understanding of the effects of broad-spectrum antibiotics on the gut microbiota and glucose homeostasis that may have future clinical implications.

Old and New Calcineurin Inhibitors in Lupus Nephritis

Calcineurin inhibitors (CNIs) are drugs that inhibit calcineurin, a key phosphatase that dephosphorylates a transcription factor called the nuclear factor of activated T cells (NFAT), allowing its translocation into the nucleus of quiescent T cells. In the nucleus, NFAT activates interleukin 2, which stimulates the proliferation and differentiation of T-cells. CNIs can also stabilize the actin cytoskeleton of podocytes reducing proteinuria. Thanks to these characteristics, CNIs have been often used in the treatment of autoimmune diseases. However, the therapeutic index of CNIs is narrow, and their interactions with other drugs can increase toxicity or reduce efficacy. In lupus nephritis, cyclosporine and tacrolimus have been used both in induction and maintenance therapies. Observational studies and randomized controlled trials showed that both cyclosporine and tacrolimus can increase efficacy. Tolerance is satisfactory if low doses are used and the patient is carefully monitored. More recently, a new CNI, called voclosporin (VCS), has been approved by the Food and Drug Administration for use in lupus nephritis. VCS offers potential advantages over other CNIs. In two large multiethnic trials, VCS was not associated with adverse renal and metabolic events and obtained positive results despite a novel and rapid corticosteroid tapering regime.

New-Onset Diabetes after Kidney Transplantation

New-onset diabetes mellitus after transplantation (NODAT) is a frequent complication in kidney allograft recipients. It may be caused by modifiable and non-modifiable factors. The non-modifiable factors are the same that may lead to the development of type 2 diabetes in the general population, whilst the modifiable factors include peri-operative stress, hepatitis C or cytomegalovirus infection, vitamin D deficiency, hypomagnesemia, and immunosuppressive medications such as glucocorticoids, calcineurin inhibitors (tacrolimus more than cyclosporine), and mTOR inhibitors. The most worrying complication of NODAT are major adverse cardiovascular events which represent a leading cause of morbidity and mortality in transplanted patients. However, NODAT may also result in progressive diabetic kidney disease and is frequently associated with microvascular complications, eventually determining blindness or amputation. Preventive measures for NODAT include a careful assessment of glucose tolerance before transplantation, loss of over-weight, lifestyle modification, reduced caloric intake, and physical exercise. Concomitant measures include aggressive control of systemic blood pressure and lipids levels to reduce the risk of cardiovascular events. Hypomagnesemia and low levels of vitamin D should be corrected. Immunosuppressive strategies limiting the use of diabetogenic drugs are encouraged. Many hypoglycemic drugs are available and may be used in combination with metformin in difficult cases. In patients requiring insulin treatment, the dose and type of insulin should be decided on an individual basis as insulin requirements depend on the patient's diet, amount of exercise, and renal function.

Long-Term Prognostic Value of Coronary CTA in Orthotopic Heart Transplant Recipients

OBJECTIVE. This study aimed to evaluate the long-term prognostic value of coronary CTA (CCTA) in heart transplant recipients. MATERIALS AND METHODS. The records of 114 patients who had undergone a heart transplant (mean age, 61.7 ± 11.1 [SD] years; 83.3% men) and who underwent CCTA for the surveillance of coronary allograft vasculopathy (CAV) from June 2007 to December 2017 were retrospectively evaluated for the occurrence of major adverse cardiovascular events (MACEs) (cardiac death, nonfatal myocardial infarction, unstable angina requiring hospitalization, coronary revascularization, cardiac arrhythmias, stroke, and retransplant). Patients were classified according to the presence of nonobstructive CAV (lumen reduction < 50%) or obstructive disease (lumen reduction ≥ 50%) and using a coronary segment involvement score (SIS). Differences in MACE rate between groups were compared. RESULTS. Obstructive CAV was observed in 12 heart transplant recipients (10.5%). During a mean follow-up of 67.5 ± 41.4 months the overall rates of MACE were 50% and 14.7% in patients with obstructive and nonobstructive CAV, respectively (p < .05), resulting in an odds ratio for MACE of 6 (95% CI, 1.7-21.2). Comparison of event-free survival showed a hazard ratio (HR) of 5 (95% CI, 1.95-13; p =. 004) for patients with obstructive disease. The presence of four or more stenotic coronary segments (SIS ≥ 4) was associated with a higher rate of events (HR, 3.46; 95% CI, 1.46-8.23). CONCLUSION. In patients who have undergone a heart transplant, CCTA offers a significant long-term prognostic impact on the prediction of MACEs.

New Onset Diabetes Mellitus After Adult Heart Transplantation and the Risk of Renal Dysfunction or Mortality

BACKGROUND

Diabetes mellitus (DM) may occur either pre-heart transplant (HT) or as new onset DM post-HT. We sought to define the contemporary incidence of post-HT DM, evaluate risk factors for post-HT DM, and assess the impact of post-HT DM on major outcomes.

METHODS

The cohort included International Society for Heart and Lung Transplantation (ISHLT) Thoracic Organ Transplant Registry adult primary HT-alone recipients, transplanted January 1995-June 2017, who survived to 1 year post-HT. DM status was characterized as (1) No DM pre- or post-HT; (2) Pre-HT DM; or (3) Post-HT DM (onset within 5 years of HT). Cox proportional hazards models were constructed to identify risk factors for post-HT DM onset, as well as risk factors for post-HT severe renal dysfunction and death/retransplantation.

RESULTS

Of 26 263 eligible subjects, 57% had no DM pre- or post-HT, 22% had pre-HT DM; 21% had new onset post-HT DM. Risk factors for the development of post-HT DM included use of tacrolimus or steroids at 1-year post-HT, as well as with higher recipient age, female sex, ischemic cardiomyopathy, higher body mass index (BMI), pre-HT dialysis, and pre-HT steroid use. Post-HT DM within 5 years was associated with increased subsequent severe renal dysfunction (hazard ratio, HR, 1.89; 95% CI 1.77, 2.01) and death/retransplantation (HR 1.38; 95% CI 1.32, 1.45), compared to patients without post-HT DM.

CONCLUSIONS

Post-HT DM is common, occurring in 21% of recipients within 5 years of HT. Post-HT DM is associated with increased risk of severe renal dysfunction and death or retransplantation.

Development of a Bioartificial Vascular Pancreas

Transplantation of pancreatic islets has been shown to be effective, in some patients, for the long-term treatment of type 1 diabetes. However, transplantation of islets into either the portal vein or the subcutaneous space can be limited by insufficient oxygen transfer, leading to islet loss. Furthermore, oxygen diffusion limitations can be magnified when islet numbers are increased dramatically, as in translating from rodent studies to human-scale treatments. To address these limitations, an islet transplantation approach using an acellular vascular graft as a vascular scaffold has been developed, termed the BioVascular Pancreas (BVP). To create the BVP, islets are seeded as an outer coating on the surface of an acellular vascular graft, using fibrin as a hydrogel carrier. The BVP can then be anastomosed as an arterial (or arteriovenous) graft, which allows fully oxygenated arterial blood with a pO2 of roughly 100 mmHg to flow through the graft lumen and thereby supply oxygen to the islets. In silico simulations and in vitro bioreactor experiments show that the BVP design provides adequate survivability for islets and helps avoid islet hypoxia. When implanted as end-to-end abdominal aorta grafts in nude rats, BVPs were able to restore near-normoglycemia durably for 90 days and developed robust microvascular infiltration from the host. Furthermore, pilot implantations in pigs were performed, which demonstrated the scalability of the technology. Given the potential benefits provided by the BVP, this tissue design may eventually serve as a solution for transplantation of pancreatic islets to treat or cure type 1 diabetes.

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.

Safety of systemic treatments for Behçet's syndrome

INTRODUCTION

Treatment of Behçet's syndrome (BS) is aimed at controlling all symptoms of such a complex disorder, ensuring a good quality of life and preventing life-threatening complications. A better understanding of the pathogenic role of different chemokines has improved our knowledge of BS and elicited a more specific use of therapies currently available, minimizing the burden of potential side-effects related to treatment.

AREAS COVERED

This work aims to provide a detailed overview of the safety profile for current therapies available in the treatment of BS, focusing on the main side-effects, toxicity and contraindications.

EXPERT OPINION

The greatest experience in the management of BS has been achieved with the employment of monoclonal anti-tumor necrosis factor antibodies which have been advocated for BS refractory manifestations. Moreover, interleukin-1 inhibitors have proven to be effective as well as safe, despite escalation of their dosage, especially to manage the most severe and difficult-to-treat ocular manifestations. However, general treatment of BS patients remains awkward as protean clinical features may respond differently to the same treatment or even worsen. Therefore, patients' safety for therapies used in BS promotes the implementation of precision medicine, which could help targeting accurately the pathogenetic mechanisms concealed behind specific clinical phenotypes.

Perioperative Glycemic Control in Patients who Underwent Cardiac Transplantation and Effect on the Outcome at Discharge in a Tertiary Care Centre

OBJECTIVES

To study the glycemic status and insulin requirements in patients who underwent cardiac transplantation and to compare it among patients with and without diabetes mellitus. To compare preoperative glycemic status and perioperative insulin requirements with the outcome.

METHODS AND MATERIALS

The retrospective data of the glycemic status of patients before and after cardiac transplantation were collected and analyzed. Different variables like HbA1c, creatinine, age, BMI, and glycemic status were compared with the outcome.

RESULTS

A total of 18 patients with a mean age of 46.72 ± 16.94 years (mean ± SD) and a median age of 48.5 years underwent cardiac transplantation. The mean preoperative glycosylated hemoglobin (HbA1c) was 8.75 ± 2.15% (72 ± 2.36 mmol/mol) and 5.82 ± 0.45% (40 ± 4.89 mmol/mol) in patients with and without diabetes mellitus, respectively. The mean insulin requirement of insulin on postoperative days 0, 1, 2, and 3 was 1.396, 0.503, 0.490, and 0.537 (IU/kg/day) in patients with diabetes, whereas in patients without diabetes mellitus it was 1.955, 0.561, 1.19, and 0.61 (IU/kg/day), respectively. The mean insulin requirement at the time of discharge was 0.698 ± 0.43 IU/kg/day (mean ± SD) and 1.285 ± 1 IU/kg/day (mean ± SD) (p = 0.36) in patients with and without diabetes mellitus, respectively (p = 0.53, 0.11, 0.41, and 0.32, respectively). There was no association with the outcome when analyzed with different variables like HbA1c, creatinine, BMI, age, hemoglobin, insulin requirements, and glycemic status.

CONCLUSIONS

Perioperative glycemic control is crucial for successful cardiac transplantation irrespective of diabetic status.

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.

Diabetes Mellitus and Osteoporosis Correlation: Challenges and Hopes

Diabetes and osteoporosis are two common diseases with different complications. Despite different therapeutic strategies, managing these diseases and reducing their burden have not been satisfactory, especially when they appear one after the other. In this review, we aimed to clarify the similarity, common etiology and possible common adjunctive therapies of these two major diseases and designate the known molecular pattern observed in them. Based on different experimental findings, we want to illuminate that interestingly similar pathways lead to diabetes and osteoporosis. Meanwhile, there are a few drugs involved in the treatment of both diseases, which most of the time act in the same line but sometimes with opposing results. Considering the correlation between diabetes and osteoporosis, more efficient management of both diseases, in conditions of concomitant incidence or cause and effect condition, is required.

Tacrolimus-induced Diabetic Ketoacidosis in a Polymyositis Patient Precipitated by Fluconazole: A Case Report and Review of the Literature

Tacrolimus is a reversible calcineurin inhibitor. It is commonly used as an immunosuppressive drug in the treatment of T cell mediated diseases such as polymyositis, graft rejection in solid organ transplant, graft-versus-host disease in hematopoietic stem cell transplant, and is postulated to have diabetogenic potential. Fluconazole, on the other hand, is frequently prescribed antifungal therapy. Fluconazole increases the serum level of tacrolimus into the supratherapeutic range, thus developing drug toxicity if the dose is unadjusted. Diabetic ketoacidosis is a rare adverse drug effect reported with the use of tacrolimus. In this report, we present a case of DKA in a 60-year-old woman with polymyositis on low dose corticosteroids and tacrolimus, precipitated by the use of fluconazole. We highlight the pathophysiologic mechanisms underlying the effect of fluconazole on tacrolimus levels causing an accelerated development of DKA along with the review of literature on this potentially life-threatening condition.

FXR activation alleviates tacrolimus-induced post-transplant diabetes mellitus by regulating renal gluconeogenesis and glucose uptake

BACKGROUND

Tacrolimus (FK506)-induced diabetes mellitus is one of the most important factors of post-transplant diabetes mellitus (PTDM). However, the detailed mechanisms underlying PTDM are still unclear. Farnesoid X receptor (FXR) regulates glycolipid metabolism. The objective of this study was to explore whether FXR is involved in the development of tacrolimus-induced diabetes mellitus.

METHODS

After C57BL/6J mice were treated with tacrolimus (FK506) for 3 months, the fasting blood glucose levels, body weights, renal morphological alterations, and mRNA expression levels of phosphoenolpyruvate carboxykinase (PEPCK) and glucose transporter 2 (GLUT2) among the control group, the FK506 group and the FK506 + GW4064 (a FXR agonist) group (n = 7) were measured. The intracellular location of peroxisome proliferator activated receptor γ coactivator-1α (PGC1α) and forkhead box O1 (FOXO1) was detected by immunofluorescence. Human renal cortex proximal tubule epithelial cells (HK-2) were treated with 15 μM FK506 or 4 μM FXR agonist (GW4064) for 24, 48 and 72 h, and the expression levels of FXR, gluconeogenesis and glucose uptake, representing the enzymes PEPCK and GLUT2, were detected with real-time PCR and western blot analyses. Finally, the mRNA levels of PEPCK and GLUT2 in HK-2 cells were measured after FXR was upregulated.

RESULTS

FK506 significantly inhibited the mRNA and protein levels of FXR at 48 h and 72 h in HK-2 cells (P < 0.05). Meanwhile, FK506 promoted gluconeogenesis and inhibited glucose uptake in HK-2 cells (P < 0.05). However, overexpression of FXR in transfected HK-2 cell lines significantly inhibited gluconeogenesis and promoted glucose uptake (P < 0.05). The FXR agonist GW4064 significantly decreased the fasting blood glucose in mice challenged with FK506 for 3 months (P < 0.05), inhibited gluconeogenesis (P < 0.05) and significantly promoted glucose uptake (P < 0.05). Immunofluorescence staining and western blot analyses further revealed that FXR activation may affect the translocation of PGC1α and FOXO1 from the nucleus to the cytoplasm.

CONCLUSIONS

FXR activation may mitigate tacrolimus-induced diabetes mellitus by regulating gluconeogenesis as well as glucose uptake of renal cortex proximal tubule epithelial cells in a PGC1α/FOXO1-dependent manner, which may be a potential therapeutic strategy for the prevention and treatment of PTDM.

Altered expression of glucose metabolism associated genes in a tacrolimus‑induced post‑transplantation diabetes mellitus in rat model

Post‑transplantation diabetes mellitus (PTDM) is a known side effect in transplant recipients administered with immunosuppressant drugs, such as tacrolimus (Tac). Although injury of islet cells is considered a major reason for Tac‑induced PTDM, the involvement of insulin resistance in PTDM remains unknown. In the present study, expression levels of adipocytokines, glucose metabolism associated genes and peroxisome proliferator‑activated receptor (PPAR)‑γ in adipose, muscular and liver tissues from a rat model induced with Tac (1 mg/kg/day) were examined. Rats developed hyperglycemia and glucose intolerance after 10 days of Tac administration. A subgroup of diabetic rats was further treated with rosiglitazone (4 mg/kg), a PPAR‑γ activator. Adipose, muscle and liver tissues were obtained on day 15 after induction and the results demonstrated that expression levels of adipocytokines, PPAR‑γ and proteins in the insulin associated signaling pathway varied in the different groups. Rosiglitazone administration significantly improved hyperglycemia, glucose intolerance and expression levels of proteins associated with insulin signaling, as well as adipocytokines expression. The results of this study demonstrated that adipocytokines and PPAR‑γ signaling may serve important roles in the pathogenesis of Tac‑induced PTDM, which may provide a promising application in the treatment of PTDM in the future.

Prevention of complications from use of conventional immunosuppressants: a critical review

Synthetic immunosuppressive drugs are largely used in immune-related renal diseases and in kidney transplantation. Most of these drugs have a low therapeutic index (the ratio that compares the blood concentration at which a drug becomes toxic and the concentration at which the drug is effective), which means that the drug should be dosed carefully and the patient monitored frequently. In this review, we consider the categories of synthetic immunosuppressive agents more frequently and conventionally used in clinical nephrology: glucocorticoids, Aalkylating agents (cyclophosphamide, chlorambucil), purine synthesis inhibitors (azathioprine, mycophenolate salts) and calcineurin inhibitors (cyclosporine, tacrolimus). For each category the possible side effects will be reviewed, the general and specific measures to prevent or treat the adverse events will be suggested, and the more common mistakes that may increase the risk of toxicity will be described. However, the efficacy and safety of immunosuppressive agents depend not only on the pharmacologic characteristics of single drugs but can be influenced also by the clinical condition and genetic characteristics of the patient, by the typology and severity of the underlying disease and by the interaction with other concomitantly used drugs.

Bilateral Central Retinal Vein Occlusion, multiple dental implants and severe glomerulonephtitis - Any connection?

We present a case of Bilateral Central Retinal Vein Occlusion in a patient who received 11 dental implants and later developed idiopathic glomerulonephritis with renal failure.

Comparison of metabolic responses to the mixed meal tolerance test vs the oral glucose tolerance test after successful clinical islet transplantation

Following islet transplantation, mixed meal tolerance tests (MMTs) are routinely utilized to assess graft function, but how the 90-minute MMTT glucose value relates to a 120-minute glucose concentration of ≥11.1 mmol/L used to diagnose diabetes following a standardized 75 g-OGTT, is not known. We examined this relationship further. Thirteen subjects with Type 1 diabetes and stable transplant grafts, not on exogenous insulin with HbA1c < 7% (53 mmol/mol), were studied on 17 occasions with paired OGTTs and MMTTs. Receiver operating characteristic (ROC) curves were constructed to derive the 90-minute MMTT glucose threshold associated with a 120-minute glucose concentration following a 75 g-OGTT (OGTT₁₂₀ ) ≥11.1 mmol/L and their diagnostic accuracy. Studies with OGTT₁₂₀ ≥11.1 mmol/L (n = 5) had diminished C-peptide: glucose, greater integrated glucose and diminished insulin: glucose area under the curve (AUC) ratios (0-120 minutes) and disposition indices; all P < .05, contrasting with MMTTs where no difference in the 90-minute glucose concentrations, C-peptide:glucose, integrated glucose, C-peptide and C-peptide: glucose AUCs (0-90 minutes) was seen; all P > .05. A 90-minute MMTT glucose concentration ≥8.0 mmol/L demonstrated a sensitivity and specificity of ≥80% for the diagnosis of OGTT₁₂₀ ≥11.1 mmol/L; area under ROC curve (mean ± SEM) 73 ± 13%. A 90-minute MMTT glucose ≥8.0 mmol/L, identifies islet transplant recipients who may require closer monitoring for graft dysfunction.

Impaired mitochondrial calcium uptake caused by tacrolimus underlies beta-cell failure

BACKGROUND

One of the most common side effects of the immunosuppressive drug tacrolimus (FK506) is the increased risk of new-onset diabetes mellitus. However, the molecular mechanisms underlying this association have not been fully clarified.

METHODS

We studied the effects of the therapeutic dose of tacrolimus on mitochondrial fitness in beta-cells.

RESULTS

We demonstrate that tacrolimus impairs glucose-stimulated insulin secretion (GSIS) in beta-cells through a previously unidentified mechanism. Indeed, tacrolimus causes a decrease in mitochondrial Ca²⁺ uptake, accompanied by altered mitochondrial respiration and reduced ATP production, eventually leading to impaired GSIS.

CONCLUSION

Our observations individuate a new fundamental mechanism responsible for the augmented incidence of diabetes following tacrolimus treatment. Indeed, this drug alters Ca²⁺ fluxes in mitochondria, thereby compromising metabolism-secretion coupling in beta-cells.

Comparison of effects of the tacrolimus and cyclosporine A on the colon anastomosis recovery of rats

Purpose

This study aims to examine and compare the effects of immunosuppressant cyclosporine A (CsA) and tacrolimus (TAC) on colon anastomosis recovery.

Methods

Forty rats were randomly divided into 4 groups. The 4 groups were determined as follows: control group; sham group, given %0.09 NaCl; TAC group, given 0.5 mg/kg/day tacrolimus; and CsA group, given 5 mg/kg/day CsA. A 6-cm midabdomen incision was performed on the rats. An incision of all layers on the right colon was performed. Then anastomosis was undertaken. Laparotomy was performed on the seventh day postoperation. The colon bursting pressures were evaluated, histopathological examinations were undertaken, and E-cadherin expression and tissue hydroxyproline levels were evaluated.

Results

Statistically significant differences were observed among bursting pressures of the groups (P < 0.001). The value was significantly low in TAC and CsA groups when compared to control and sham groups (P < 0.05). The tissue hydroxyproline levels were significantly low in TAC group compared to control group (P = 0.03). Fibroblast density and neovascularization were significantly greater in the control group compared to the TAC group (P < 0.05). Levels of collagen had decreased significantly in TAC group compared to other groups (P < 0.05).

Conclusion

Our study showed that TAC may have a negative effect of colon anastomosis recovery. The lowest anastomosis bursting pressure was detected in TAC group. Also, collagen, hydroxyproline, fibroblast, neovascularization and E-Cadherin levels were comparatively lower in TAC group. CsA did not cause any significant changes to tissue hydroxyproline, collagen, fibroblast, and E-Cadherin levels.