Tacrolimus in pancreas transplant: a focus on toxicity, diabetogenic effect and drug–drug interactions

Retrospective analysis on incidence and risk factors of post-transplant diabetes mellitus after lung transplantation and its association with clinical outcomes

BACKGROUND

Post-transplant diabetes mellitus (PTDM) is a common complication after transplantation. We aim to explore potential risk factors of PTDM and its association with outcomes after lung transplantation (LTx).

METHODS

A retrospective study was conducted in 100 patients who underwent LTx at our institution from 2017 to 2021. Patients' information was collected, and genotyping for single nucleotide polymorphisms known to potentially increase the risk of Type 2 DM was performed. Univariate and multivariate analyses were conducted to identify risk factors for PTDM. The primary outcome was the incidence of PTDM. Secondary outcomes were associations between PTDM and clinical outcomes following LTx.

RESULTS

Thirty-nine patients (39.0%) developed PTDM, while 10 patients (25.6%) recovered subsequently. The incidence of PTDM was associated with age > 45 (HR: 2.919, 95% CI [1.021-8.348]), pre-transplant HbA1c > 5.7% (HR: 2.344, 95% CI [1.201-4.573]), KCNJ11 rs5215 (HR: 2.090, 95% CI [1.050-4.162]) and tacrolimus concentration > 8 ng/mL in the first month (HR: 2.090, 95% CI [1.050-4.162]). Patients with PTDM experienced elevated fasting blood glucose levels (FBG) during the first month post-transplantation (p < 0.001), and required a longer duration for FBG to return to normal levels (p < 0.001). However, the presence of PTDM did not significantly impact renal function, incidence of infection episodes, chronic lung allograft dysfunction or mortality following LTx.

CONCLUSION

Advanced age, elevated HbA1c levels, KCNJ11 gene polymorphism, and early exposure to tacrolimus are all significant risk factors for PTDM following LTx. The clinical implications of these factors warrant attention.

Vancomycin relieves tacrolimus-induced hyperglycemia by eliminating gut bacterial beta-glucuronidase enzyme activity

Up to 40% of transplant recipients treated long-term with tacrolimus (TAC) develop post-transplant diabetes mellitus (PTDM). TAC is an important risk factor for PTDM, but is also essential for immunosuppression after transplantation. Long-term TAC treatment alters the gut microbiome, but the mechanisms of TAC-induced gut microbiota in the pathogenesis of PTDM are poorly characterized. Here, we showed that vancomycin, an inhibitor of bacterial beta-glucuronidase (GUS), prevents TAC-induced glucose disorder and insulin resistance in mice. Metagenomics shows that GUS-producing bacteria are predominant and flourish in the TAC-induced hyperglycemia mouse model, with upregulation of intestinal GUS activity. Targeted metabolomics analysis revealed that in the presence of high GUS activity, the hydrolysis of bile acid (BAs)-glucuronic conjugates is increased and most BAs are overproduced in the serum and liver, which, in turn, activates the ileal farnesoid X receptor (FXR) and suppresses GLP-1 secretion by L-cells. The GUS inhibitor vancomycin significantly eliminated GUS-producing bacteria and inhibited bacterial GUS activity and BAs levels, thereby enhancing L-cell GLP-1 secretion and preventing hyperglycemia. Our results propose a novel clinical strategy for inhibiting the bacterial GUS enzyme to prevent hyperglycemia without requiring withdrawal of TAC treatment. This strategy exerted its effect through the ileal bile acid-FXR-GLP-1 pathway.

Impact of early corticosteroid withdrawal on simultaneous pancreas-kidney transplant long-term outcomes: Single center experience and comparison to the International Pancreas Transplant Registry

BACKGROUND

There remains a paucity of modern data comparing early steroid withdrawal (ESW) versus chronic corticosteroid (CCS) immunosuppression in simultaneous pancreas kidney (SPK) transplant recipients with long-term follow-up. Therefore, the purpose of this study is to assess the effectiveness and tolerability of ESW compared to CCS post-SPK.

METHODS

This was a retrospective single-center matched comparison with the International Pancreas Transplant Registry (IPTR). Patients from University of Illinois Hospital (UIH) represented the ESW group and were compared to those matched CCS patients from the IPTR. Included patients were adult recipients of a primary SPK transplant between 2003 and 2018 within the US receiving rabbit anti-thymocyte globulin induction. Patients were excluded if they had early technical failures, missing IPTR data, graft thrombosis, re-transplant, or positive crossmatch SPK.

RESULTS

A total of 156 patients were matched and included in the analysis. Patients were predominantly African American (46.15%) males (64.1%) with Type 1 diabetes etiology (92.31%). Overall pancreas allograft survival (hazard ratio [HR] = .89, 95% confidence interval [CI] .34-2.30, p = .81) and kidney allograft survival (HR = .80, 95%CI .32-2.03, p = .64) were similar between the two groups. Immunologic pancreas allograft loss was statistically similar at 1-year (ESW 1.3% vs. CCS 0%, p = .16), 5-year (ESW 1.3% vs. CCS 7.7%, p = .16), and 10-year (ESW 11.0% vs. CCS 7.7%, p = .99). The 1-year (ESW 2.6% vs. CCS 0%, p > .05), 5-year (ESW 8.3% vs. CCS 7.0%, p > .05), and 10-year (ESW 22.7% vs. CCS 9.9%, p = .2575) immunologic kidney allograft loss were also statistically similar. There was no difference in 10-year overall patient survival (ESW 76.2% vs. CCS 65.6%, p = .63).

CONCLUSIONS

No differences were found between allograft or patient survival post-SPK when comparing an ESW or CCS protocol. Future assessment is needed to determine differences in metabolic outcomes.

A comprehensive update of the metabolic and toxicological considerations for immunosuppressive drugs used during pancreas transplantation

INTRODUCTION

Despite significant advancements in immunosuppressive regimens and surgical techniques, the prevalence of adverse events related to immunosuppression remains a major challenge affecting the long-term survival rates of pancreas and kidney allografts.

AREAS COVERED

This article presents a comprehensive review of the literature and knowledge (Jan/2012-Feb/2023) concerning glucose metabolism disorders and nephrotoxicity associated with tacrolimus and mammalian target of rapamycin inhibitors (mTORi). Novel signaling pathways potentially implicated in these adverse events are discussed. Furthermore, we extensively examine the findings from clinical trials evaluating the efficacy and safety of tacrolimus, mTORi, and steroid minimization.

EXPERT OPINION

Tacrolimus-based regimens continue to be the standard treatment following pancreas transplants. However, prolonged use of tacrolimus and mTORi may lead to hyperglycemia and nephrotoxicity. Understanding and interpreting experimental data, particularly concerning novel signaling pathways beyond calcineurin-NFAT and mTOR pathways, can offer valuable insights for therapeutic interventions to mitigate hyperglycemia and nephrotoxicity. Additionally, critically analyzing clinical trial results can identify opportunities for personalized safety-based approaches to minimize side effects. It is imperative to conduct randomized-controlled studies to assess the impact of mTORi use and steroid-free protocols on pancreatic allograft survival. Such studies will aid in tailoring treatment strategies for improved transplant outcomes.

Human hypoimmune primary pancreatic islets avoid rejection and autoimmunity and alleviate diabetes in allogeneic humanized mice

Transplantation of allogeneic pancreatic donor islets has successfully been performed in selected patients with difficult-to-control insulin-dependent diabetes and impaired awareness of hypoglycemia (IAH). However, the required systemic immunosuppression associated with this procedure prevents this cell replacement therapy from more widespread adoption in larger patient populations. We report the editing of primary human islet cells to the hypoimmune HLA class I- and class II-negative and CD47-overexpressing phenotype and their reaggregation into human HIP pseudoislets (p-islets). Human HIP p-islets were shown to survive, engraft, and ameliorate diabetes in immunocompetent, allogeneic, diabetic humanized mice. HIP p-islet cells were further shown to avoid autoimmune killing in autologous, diabetic humanized autoimmune mice. The survival and endocrine function of HIP p-islet cells were not impaired by contamination of unedited or partially edited cells within the p-islets. HIP p-islet cells were eliminated quickly and reliably in this model using a CD47-targeting antibody, thus providing a safety strategy in case HIP cells exert toxicity in a future clinical setting. Transplantation of human HIP p-islets for which no immunosuppression is required has the potential to lead to wider adoption of this therapy and help more diabetes patients with IAH and history of severe hypoglycemic events to achieve insulin independence.

Role of topical and systemic immunosuppression in aqueous-deficient dry eye disease

Immunosuppression in aqueous-deficient dry eye disease (ADDE) is required not only to improve the symptoms and signs but also to prevent further progression of the disease and its sight-threatening sequelae. This immunomodulation can be achieved through topical and/or systemic medications, and the choice of one drug over the other is determined by the underlying systemic disease. These immunosuppressive agents require a minimum of 6-8 weeks to achieve their beneficial effect, and during this time, the patient is usually placed on topical corticosteroids. Antimetabolites such as methotrexate, azathioprine, and mycophenolate mofetil, along with calcineurin inhibitors, are commonly used as first-line medications. The latter have a pivotal role in immunomodulation since T cells contribute significantly to the pathogenesis of ocular surface inflammation in dry eye disease. Alkylating agents are largely limited to controlling acute exacerbations with pulse doses of cyclophosphamide. Biologic agents, such as rituximab, are particularly useful in patients with refractory disease. Each group of drugs has its own side-effect profiles and requires a stringent monitoring schedule that must be followed to prevent systemic morbidity. A customized combination of topical and systemic medications is usually required to achieve adequate control, and this review aims to help the clinician choose the most appropriate modality and monitoring regimen for a given case of ADDE.

Hypoglycemia with insulin in post-transplant diabetes mellitus

INTRODUCTION

To prevent hypoglycemic episodes, the management of insulin therapy against post-transplant diabetes mellitus (PTDM) is important. We compared glargine (long-acting insulin) versus NPH isophane (intermediate-acting insulin) as an armamentarium against PTDM. Indeed, the study evaluated PTDM patients with hypoglycemic episodes treated with isophane or glargine.

MATERIAL AND METHODS

We evaluated a total number of 231 living-donor renal transplant recipients with PTDM of age ≥ 18 years admitted to the hospital between January 2017 and September 2021. However, patients taking hypoglycemic agents before transplantation were excluded from this study. Out of 231 patients, 52 (22.15%) suffered from PTDM out of whom 26 were treated with glargine or isophane.

RESULTS

After applying exclusion criteria, out of 52 PTDM patients 23 were included in the study: 13 PTDM patients were treated with glargine, whereas 10 PTDM patients with isophane. Our analysis revealed 12 episodes of hypoglycemia in glargine-treated PTDM patients compared to 3 in isophane-treated PTDM patients (p = 0.056). Clinically, 9 out of 15 hypoglycemic episodes were nocturnal (60%). Furthermore, no other risk factors were observed in our study population. Detailed analysis showed that both groups had equivalent doses of immunosuppressants and oral hypoglycemic agents. The odds ratio for hypoglycemia in the group treated with isophane compared to that treated with glargine was 0.224 (95% CI, 0.032-1.559). Glargine users recorded significantly lower blood sugar levels before lunch, dinner and at bedtime with p-values of 0.001, 0.009 and 0.001 respectively. A better hemoglobin A1c (HbA1c) level was seen in the glargine vs. isophane group (6.98 ± 0.52 vs. 7.45 ± 0.49, p-value 0.03).

CONCLUSION

The study shows better blood sugar control with long-acting insulin analog, glargine, than with intermediate-actin analog, isophane. Overall, a higher number of hypoglycemic episodes was nocturnal. Long term safety of long-acting insulin analogs needs to be further studied.

Cell Replacement Therapy for Type 1 Diabetes Patients: Potential Mechanisms Leading to Stem-Cell-Derived Pancreatic β-Cell Loss upon Transplant

Cell replacement therapy using stem-cell-derived insulin-producing β-like cells (sBCs) has been proposed as a practical cure for patients with type one diabetes (T1D). sBCs can correct diabetes in preclinical animal models, demonstrating the promise of this stem cell-based approach. However, in vivo studies have demonstrated that most sBCs, similarly to cadaveric human islets, are lost upon transplantation due to ischemia and other unknown mechanisms. Hence, there is a critical knowledge gap in the current field concerning the fate of sBCs upon engraftment. Here we review, discuss effects, and propose additional potential mechanisms that could contribute toward β-cell loss in vivo. We summarize and highlight some of the literature on phenotypic loss in β-cells under both steady, stressed, and diseased diabetic conditions. Specifically, we focus on β-cell death, dedifferentiation into progenitors, trans-differentiation into other hormone-expressing cells, and/or interconversion into less functional β-cell subtypes as potential mechanisms. While current cell replacement therapy efforts employing sBCs carry great promise as an abundant cell source, addressing the somewhat neglected aspect of β-cell loss in vivo will further accelerate sBC transplantation as a promising therapeutic modality that could significantly enhance the life quality of T1D patients.

Sustained Release of Tacrolimus Embedded in a Mixed Thermosensitive Hydrogel for Improving Functional Recovery of Injured Peripheral Nerves in Extremities

Vascularized composite allotransplantation is an emerging strategy for the reconstruction of unique defects such as amputated limbs that cannot be repaired with autologous tissues. In order to ensure the function of transplanted limbs, the functional recovery of the anastomosed peripheral nerves must be confirmed. The immunosuppressive drug, tacrolimus, has been reported to promote nerve recovery in animal models. However, its repeated dosing comes with risks of systemic malignancies and opportunistic infections. Therefore, drug delivery approaches for locally sustained release can be designed to overcome this issue and reduce systemic complications. We developed a mixed thermosensitive hydrogel (poloxamer (PLX)-poly(l-alanine-lysine with Pluronic F-127) for the time-dependent sustained release of tacrolimus in our previous study. In this study, we demonstrated that the hydrogel drug degraded in a sustained manner and locally released tacrolimus in mice over one month without affecting the systemic immunity. The hydrogel drug significantly improved the functional recovery of injured sciatic nerves as assessed using five-toe spread and video gait analysis. Neuroregeneration was validated in hydrogel-drug-treated mice using axonal analysis. The hydrogel drug did not cause adverse effects in the mouse model during long-term follow-up. The local injection of encapsulated-tacrolimus mixed thermosensitive hydrogel accelerated peripheral nerve recovery without systemic adverse effects.

Therapeutic Potential of Bioactive Components from Scutellaria baicalensis Georgi in Inflammatory Bowel Disease and Colorectal Cancer: A Review

Scutellaria baicalensis Georgi (SBG), an herbal medicine with various biological activities, including anti-inflammatory, anticancer, antiviral, antibacterial, and antioxidant activities, is effective in treatment of colitis, hepatitis, pneumonia, respiratory infections, and allergic diseases. This herbal medicine consists of major active substances, such as baicalin, baicalein, wogonoside, and wogonin. Inflammatory bowel disease (IBD) comprises a group of inflammatory conditions of the colon and small intestine, with Crohn's disease and ulcerative colitis being the main types. IBD can lead to serious complications, such as increased risk of colorectal cancer (CRC), one of the most common cancers worldwide. Currently, there is no cure for IBD, and its incidence has been increasing over the past few decades. This review comprehensively summarizes the efficacy of SBG in IBD and CRC and may serve as a reference for future research and development of drugs for IBD and cancer treatment.

The Effect of Voriconazole on Tacrolimus in Kidney Transplantation Recipients: A Real-World Study

Tacrolimus is an immunosuppressant with a narrow therapeutic window. Tacrolimus exposure increased significantly during voriconazole co-therapy. The magnitude of this interaction is highly variable, but it is hard to predict quantitatively. We conducted a study on 91 kidney transplantation recipients with voriconazole co-therapy. Furthermore, 1701 tacrolimus concentration data were collected. Standard concentration adjusted by tacrolimus daily dose (C/D) and weight-adjusted standard concentration (CDW) increased to 6 times higher during voriconazole co-therapy. C/D and CDW increased with voriconazole concentration. Patients with the genotype of CYP3A5 *3/*3 and CYP2C19 *2/*2 or *2/*3 were more variable at the same voriconazole concentration level. The final prediction model could explain 54.27% of the variation in C/D and 51.11% of the variation in CDW. In conclusion, voriconazole was the main factor causing C/D and CDW variation, and the effect intensity should be quantitative by its concentration. Kidney transplant recipients with CYP3A5 genotype of *3/*3 and CYP2C19 genotype of *2/*2 and *2/*3 should be given more attention during voriconazole co-therapy. The prediction model established in this study may help to reduce the occurrence of rejection.

The effect of tacrolimus-induced toxicity on metabolic profiling in target tissues of mice

Tacrolimus (Tac) is a common immunosuppressant that used in organ transplantation. However, its therapeutic index is narrow, and it is prone to adverse side effects, along with an increased risk of toxicity, namely, cardio-, nephro-, hepato-, and neurotoxicity. Prior metabolomic investigations involving Tac-driven toxicity primarily focused on changes in individual organs. However, extensive research on multiple matrices is uncommon. Hence, in this research, the authors systemically evaluated Tac-mediated toxicity in major organs, namely, serum, brain, heart, liver, lung, kidney, and intestines, using gas chromatography-mass spectrometry (GC-MS). The authors also employed multivariate analyses, including orthogonal projections to the latent structure (OPLS) and t-test, to screen 8 serum metabolites, namely, D-proline, glycerol, D-fructose, D-glucitol, sulfurous acid, 1-monopalmitin (MG (16:0/0:0/0:0)), glycerol monostearate (MG (0:0/18:0/0:0)), and cholesterol. Metabolic changes within the brain involved alterations in the levels of butanamide, tartronic acid, aminomalonic acid, scyllo-inositol, dihydromorphine, myo-inositol, and 11-octadecenoic acid. Within the heart, the acetone and D-fructose metabolites were altered. In the liver, D-glucitol, L-sorbose, palmitic acid, myo-inositol, and uridine were altered. In the lung, L-lactic acid, L-5-oxoproline, L-threonine, phosphoric acid, phosphorylethanolamine, D-allose, and cholesterol were altered. Lastly, in the kidney, L-valine and D-glucose were altered. Our findings will provide a systematic evaluation of the metabolic alterations in target organs within a Tac-driven toxicity mouse model.

Recurrent Cytomegalovirus Infection Controlled by the Introduction of Everolimus in a Simultaneous Pancreas-Kidney Transplantation Recipient: A Case Report

In simultaneous pancreas-kidney transplantation (SPK) recipients, cytomegalovirus (CMV) infection is a major complication that has been associated with the use of tacrolimus (TAC)-based immunosuppression. As one of the immunosuppressive drug options, the use of mammalian target of rapamycin inhibitors (mTORi) results in reduced rates of CMV infection in the field of solid organ transplantation. However, little is known about mTORi usage in pancreas transplantation. We report a case of recurrent CMV infection that was controlled by the introduction of mTORi (everolimus) in addition to a TAC-based immunosuppression regimen in SPK. A 52-year-old man underwent SPK. Graft duodenal perforation occurred on the 13th day of surgery, and graft duodenal resection was performed after long-term abscess drainage treatment. After graft duodenal resection, he was diagnosed with CMV viremia, and valganciclovir was started. However, because of recurrent febrile neutropenia caused by cytopenia as a side effect of valganciclovir, there was a repeated need for granulocyte-colony stimulating factor treatment. Immunosuppressive drug taper adjustment was attempted to control recurrent CMV viremia, and everolimus was introduced with the aim of reducing the dose of TAC and mycophenolate mofetil. This resulted in a continuously negative CMV antigenemia test and a stable general condition. Understanding the characteristics of various immunosuppressive agents and appropriately controlling and managing infectious diseases is crucial for the good postoperative management of patients with SPK.

Hyaluronic acid methacrylate/pancreatic extracellular matrix as a potential 3D printing bioink for constructing islet organoids

Islet transplantation has poor long-term efficacy because of the lack of extracellular matrix support and neovascularization; this limits its wide application in diabetes research. In this study, we develop a 3D-printed islet organoid by combining a pancreatic extracellular matrix (pECM) and hyaluronic acid methacrylate (HAMA) as specific bioinks. The HAMA/pECM hydrogel was validated in vitro to maintain islet cell adhesion and morphology through the Rac1/ROCK/MLCK signaling pathway, which helps improve islet function and activity. Further, in vivo experiments confirmed that the 3D-printed islet-encapsulated HAMA/pECM hydrogel increases insulin levels in diabetic mice, maintains blood glucose levels within a normal range for 90 days, and rapidly secretes insulin in response to blood glucose stimulation. In addition, the HAMA/pECM hydrogel can facilitate the attachment and growth of new blood vessels and increase the density of new vessels. Meanwhile, the designed 3D-printed structure was conducive to the formation of vascular networks and it promoted the construction of 3D-printed islet organoids. In conclusion, our experiments optimized the HAMA/pECM bioink composition and 3D-printed structure of islet organoids with promising therapeutic effects compared with the HAMA hydrogel group that can be potentially used in clinical applications to improve the effectiveness and safety of islet transplantation in vivo. STATEMENT OF SIGNIFICANCE: The extraction process of pancreatic islets can easily cause damage to the extracellular matrix and vascular system, resulting in poor islet transplantation efficiency. We developed a new tissue-specific bioink by combining pancreatic extracellular matrix (pECM) and hyaluronic acid methacrylate (HAMA). The islet organoids constructed by 3D printing can mimic the microenvironment of the pancreas and maintain islet cell adhesion and morphology through the Rac1/ROCK/MLCK signaling pathway, thereby improving islet function and activity. In addition, the 3D-printed structures we designed are favorable for the formation of new blood vessel networks, bringing hope for the long-term efficacy of islet transplantation.

Effect of dual inhibition of DPP4 and SGLT2 on tacrolimus-induced diabetes mellitus and nephrotoxicity in a rat model

Sodium/glucose co-transporter-2 inhibitor (SGLT2i) or dipeptidyl peptidase IV inhibitor (DPP4i) is a newer anti-diabetic drug in type II diabetes mellitus (DM), but their use in tacrolimus (TAC)-induced DM is still undetermined. We performed this study to evaluate the effect of these two drugs in TAC-induced DM and nephrotoxicity in ex vivo and in vivo. In the experimental Sprague Dawley rat model of TAC-induced DM and nephrotoxicity, dual inhibition of DPP4 and SGLT2 significantly decreased blood glucose level, HbA1C and increased plasma insulin levels and pancreatic islet size compared with each drug. In the kidney, dual inhibition improved renal function decreased interstitial fibrosis and profibrotic cytokines compared with DPP4i and SGLT2i alone. Increased oxidative stress by TAC was remarkably decreased with DPP4i or SGLT2i in serum, pancreatic and renal tissues and this decrease was much more significant in the combination group. In in vitro study, TAC decreased the cell viability of human kidney-2(HK-2) cells and insulin-secreting beta-cell-derived line(INS-1) cells. SGLT2i protected TAC-induced cell death in HK-2 cells, but not in INS-1 cells. The addition of DPP4i to SGLT2i compensated for a lack of protective effect of SGLT2i on INS-1 cells. This finding provides the rationale for the combined treatment of SGLG2i and DPP4i in TAC-induced DM and nephrotoxicity.

Therapeutic effect of baicalin on inflammatory bowel disease: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Baicalin (BI) is an important biologically active flavonoid isolated from the root of Scutellaria radix (Huang Qin). Traditionally Scutellaria radix was the common drug of dysentery. As the main flavonoid compound, there is a distribution tendency of baicalin to the intestinal tract and it has a protective effect on the gastrointestinal tract.

AIM OF THE REVIEW

This review aims to compile up-to-date and comprehensive information on the efficacy of baicalin in vitro and in vivo, about treating inflammatory bowel disease. Relevant information on the therapeutic potential of baicalin against inflammatory bowel disease was collected from the Web of Science, Pubmed and so on. Additionally, a few books and magazines were also consulted to get the important information.

RESULTS

The mechanisms of baicalin against inflammatory bowel disease mainly include anti-inflammation, antioxidant, immune regulation, maintenance of intestinal barrier, maintenance of intestinal flora balance. Also, BI can relieve parts of extraintestinal manifestations (EIMs), and prevent colorectal cancer.

CONCLUSION

Baicalin determined the promising therapeutic prospects as potential supplementary medicines for the treatment of IBD.

Tacrolimus inhibits insulin release and promotes apoptosis of Min6 cells through the inhibition of the PI3K/Akt/mTOR pathway

As a calcineurin inhibitor, tacrolimus is commonly used as a first‑line immunosuppressant in organ transplant recipients. Post‑transplantation diabetes mellitus (PTDM) is a common complication following kidney transplantation and is associated with immunosuppressant drugs, such as tacrolimus. PTDM caused by tacrolimus may be related to its influence on insulin secretion and insulin resistance. However, the specific mechanism has not been fully elucidated. The aim of the present study was to investigate whether the PI3K/Akt/mTOR signaling pathway served an important role in the pathogenesis of PTDM induced by tacrolimus. In the present study, the Cell Counting Kit‑8 assay was used to measure the effect of tacrolimus on the viability of Min6 mouse insulinoma cells. The effects of tacrolimus on the insulin secretion and the activity of caspase‑3 of Min6 cells stimulated by glucose exposure were measured by ELISA. Superoxide dismutase (SOD) and malondialdehyde (MDA) levels were measured using WST‑8 and thiobarbituric acid assays, respectively. The effects of tacrolimus on the mRNA expression levels of PI3K, Akt and mTOR were detected by reverse transcription‑quantitative PCR (RT‑qPCR), whereas the protein expression levels of PI3K, Akt, mTOR, phosphorylated (p)‑AKT and p‑mTOR in Min6 cells were assessed using western blotting. The present data indicated that, compared with the control group, 5, 25 and 50 ng/ml tacrolimus treatment could inhibit the insulin secretion of Min6 cells stimulated by glucose solution, and 50 ng/ml tacrolimus could notably decrease the stimulation index (P<0.05). Moreover, 50 ng/ml tacrolimus markedly increased the activity of caspase‑3 by 175.1% (P<0.05), it also decreased the SOD activity (P<0.01) and increased MDA levels (P<0.05). The RT‑qPCR results demonstrated that the mRNA expression levels of PI3K, Akt and mTOR were downregulated by 25 and 50 ng/ml tacrolimus (P<0.01). Furthermore, the western blotting results suggested that tacrolimus had no significant effects on the expression levels of total PI3K, Akt and mTOR proteins (P>0.05), but 25 and 50 ng/ml tacrolimus could significantly inhibit the expression levels of p‑Akt and p‑mTOR (P<0.01). In conclusion, tacrolimus decreased the activity and insulin secretion of pancreatic β cells and induced the apoptosis of islet β cells by inhibiting the mRNA expression levels of PI3K, Akt and mTOR and reducing the phosphorylation of Akt and mTOR proteins in the PI3K/Akt/mTOR signaling pathway, which may ultimately lead to the occurrence of diabetes mellitus, and may be considered as one of the specific mechanisms of PTDM caused by tacrolimus.

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.

Effects of Different Tacrolimus Doses on Adipose-Derived Stem Cells

OBJECTIVES

Tacrolimus is currently one of the most commonly used immunosuppressant agents to prevent rejection in organ transplant. Although modern immunosuppressive agents have been successful, rejection cannot be completely prevented. Therefore, in organ transplant research, additional treatment methods are being investigated, with the most important one being stem cell therapy. In addition to tacrolimus therapy, stem cell therapy is now clinically applicable, with frequency of concomitant use seeming to expand in the future. In this study, the effects of tacrolimus on stem cells were investigated.

MATERIALS AND METHODS

Adipose-derived stem cells were treated with tacrolimus at different doses and time points. We analyzed the effects of changes in stem cell proliferation using MTT analysis. Sox2, Oct3/4, and Nanog protein levels were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to measure stem cell pluripotency capabilities.

RESULTS

Our observations showed that tacrolimus causes changes in stem cell proliferation and pluripotency, with changes dependent on time and dose.

CONCLUSIONS

The dose of tacrolimus and the time of application of stem cells are important in the planning of stem cell therapy in organ transplant.

Late Conversion to Sirolimus or Everolimus After Pancreas Transplant

BACKGROUND

Pancreas transplant is an effective treatment for insulin-dependent diabetic individuals with end-stage renal disease, yet immunosuppression-associated adverse events may adversely affect patient and graft survival. The aim of the study was to document whether mammalian target of rapamycin inhibitors (mTORi) are safe and effective as a second-line drug after pancreas transplant.

METHODOLOGY

An observational single-center study was performed in a cohort of 490 simultaneous pancreas-kidney transplant and 45 pancreas-after-kidney transplant individuals after conversion to mTORi (n = 13) owing to adverse events of either tacrolimus or mycophenolate.

RESULTS

mTORi conversion was performed 11.5 ± 10.1 (range, 1-28) months after pancreas transplant, mainly owing to cytomegalovirus infection and gastrointestinal intolerance. We frequently observed clinical complications after mTORi conversion, yet creatinine, eGFR, proteinuria, fasting plasma glucose, HbA1c, and C-peptide remained stable throughout the study (mean follow-up 8.2 ± 5, range 1-17) years, as did the lipid profile (P > .05). However, graft loss occurred in almost 20% of patients owing to chronic alterations.

LIMITATIONS

The small number of patients and a single-center cohort were limitations of the study.

CONCLUSIONS

Late mTORi conversion is a safe and effective approach when tacrolimus or mycophenolate-mediated adverse events occur after pancreas transplant.

Modifiable Variables Are Major Risk Factors for Posttransplant Diabetes Mellitus in a Time-Dependent Manner in Kidney Transplant: An Observational Cohort Study

Modifiable and nonmodifiable risk factors for developing posttransplant diabetes mellitus (PTDM) have already been established in kidney transplant setting and impact adversely both patient and allograft survival. We analysed 450 recipients of living and deceased donor kidney transplants using current immunosuppressive regimen in the modern era and verified PTDM prevalence and risk factors over three-year posttransplant. Tacrolimus (85%), prednisone (100%), and mycophenolate (53%) were the main immunosuppressive regimen. Sixty-one recipients (13.5%) developed PTDM and remained in this condition throughout the study, whereas 74 (16.5%) recipients developed altered fasting glucose over time. Univariate analyses demonstrated that recipient age (46.2 ± 1.3vs. 40.7 ± 0.6 years old, OR 1.04; P = 0.001) and pretransplant hyperglycaemia and BMI ≥ 25 kg/m2 (32.8% vs. 21.6%, OR 0.54; P = 0.032 and 57.4% vs. 27.7%, OR 3.5; P < 0.0001, respectively) were the pretransplant variables associated with PTDM. Posttransplant transient hyperglycaemia (86.8%. 18.5%, OR 0.03; P = 0.0001), acute rejection (P = 0.021), calcium channel blockers (P = 0.014), TG/HDL (triglyceride/high-density lipoprotein cholesterol) ratio ≥ 3.5 at 1 year (P = 0.01) and at 3 years (P = 0.0001), and tacrolimus trough levels at months 1, 3, and 6 were equally predictors of PTDM. In multivariate analyses, pretransplant hyperglycaemia (P = 0.035), pretransplant BMI ≥ 25 kg/m2 (P = 0.0001), posttransplant transient hyperglycaemia (P = 0.0001), and TG/HDL ratio ≥ 3.5 at 3-year posttransplant (P = 0.003) were associated with PTDM diagnosis and maintenance over time. Early identification of risk factors associated with increased insulin resistance and decreased insulin secretion, such as pretransplant hyperglycaemia and overweight, posttransplant transient hyperglycaemia, tacrolimus trough levels, and TG/HDL ratio may be useful for risk stratification of patients to determine appropriate strategies to reduce PTDM.

The use of LCP-Tacrolimus (Envarsus XR) in simultaneous pancreas and kidney (SPK) transplant recipients

BACKGROUND

Extended release LCP-tacrolimus (LCPT) allows once-daily dosing in transplant recipients. The improved bioavailability may be beneficial for simultaneous pancreas-kidney recipients (SPK).

METHODS

This is a study of 39 SPK recipients on standard immediate-release tacrolimus (IR-TAC, n = 21) or LCPT (n = 18). Coefficient of variability (CV = 100∗standard deviation/mean) was calculated to assess drug levels. Hemoglobin A1c (HbA1c), tacrolimus and creatinine levels were measured postoperatively.

RESULTS

There was no difference in tacrolimus CV in the IR-TAC and LCPT groups at 1 month or 3 months postoperatively; however, a greater difference was observed at 1 year (41.0 vs. 33.1%; p = 0.19). There were six episodes of acute rejection in the IR-TAC group compared to zero episodes in the LCPT group (p = 0.01). HbA1c was significantly higher in the IR-TAC group compared to LCPT at 3 (5.5 vs. 4.9%, p = 0.01), 6 (5.6 vs. 4.9%, p = 0.01) and 12 months (5.8 vs. 5.1%, p = 0.07).

CONCLUSIONS

Significantly lower rates of rejection were observed in patients receiving LCPT. The once daily dosing may facilitate medication adherence and result in improved long-term outcomes.

PRODIG (Prevention of new onset diabetes after transplantation by a short term treatment of Vildagliptin in the early renal post-transplant period) study: study protocol for a randomized controlled study

BACKGROUND

Post-transplant diabetes is a frequent and serious complication of kidney transplantation. There is currently no treatment to prevent or delay the disease. Nevertheless, identification of risk factors make it possible to target a population at risk of developing de novo diabetes. We hypothesized that a short-term treatment with vildagliptin may prevent new onset diabetes after transplantation (NODAT) in high-risk patients.

METHODS/DESIGN

This is a multicenter, double-blind, placebo-controlled randomized clinical trial. Patients undergoing first kidney transplantation will be included from ten French transplant centers. Included patients will be randomized (1:1) to receive either vildagliptin 100 or 50 mg/day (depending on glomerular filtration rate) during 2 months (the first dose being administered before entering the operating theatres) or placebo. Additional antidiabetic therapy could be administered according to glycemic control. The primary outcome is the proportion of diabetic patients 1 year after transplantation, defined as patients receiving a diabetic treatment, or having a fasting glucose above 7 mmol/l, and/or with an abnormal oral glucose tolerance test. Secondary outcomes include glycated hemoglobin, the occurrence of acute rejection, infection, graft loss and patient death at 3 months, 6 months, and 12 months after transplantation. Outcomes will be correlated to clinical and general characteristics of the patient, cardiovascular history, nephropathy, dialysis history, transplantation data, biological data, health-related quality of life, and the cost-effectiveness of prevention of diabetes with vildagliptin.

DISCUSSION

We have scarce data on the pharmacological prevention of post-transplant diabetes. If our hypothesis is verified, our results will have a direct application in clinical practice and could limit diabetes-associated morbidity, reduce cardiovascular complications, increase quality of life of renal transplant patients, and consequently promote graft and patient survival. Our results may possibly serve for non-transplant patients carrying a high-risk of diabetes associated with other co-morbidities.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02849899 . Registered on 8 February 2016.

Tacrolimus Suppositories in Therapy-Resistant Ulcerative Proctitis

Background

Ulcerative proctitis may often be managed with topical salicylates or steroids alone, but in some patients, symptoms are persistent and severe. We analyzed the efficacy of tacrolimus suppositories in patients who had proven refractory to combined topical and systemic treatment.

Methods

In this retrospective analysis, ulcerative colitis activity index (CAI), side effects, co-medication and drug levels were assessed in 43 patients with distal ulcerative colitis who received suppositories containing 2 mg of tacrolimus b.i.d. as add-on medication.

Results

A total of 23 patients with ulcerative proctitis presented to follow-up within ≤50 days (mean 27.0 days) after suppositories were started. A decrease in CAI (from 8.0 to 5.5 points) was observed and 52.3% reached clinical remission (CAI ≤4). In total, 43 patients were available for analysis, of whom 9 had inflammation of the sigmoid colon as well. For the entire cohort, the median treatment duration was 76 days; 60% were in remission on the last documented visit. Serum measurements revealed a substantial tacrolimus level with a mean of 5.5 ng/mL. We observed one case of mild reversible acute kidney injury.

Conclusions

In ulcerative proctitis, adding tacrolimus suppositories can be an effective and safe option when topical mesalazine, corticoid formulations and concomitant oral or parenteral medications have failed.

The Fate of Allogeneic Pancreatic Islets following Intraportal Transplantation: Challenges and Solutions

Pancreatic islet transplantation as a therapeutic option for type 1 diabetes mellitus is gaining widespread attention because this approach can restore physiological insulin secretion, minimize the risk of hypoglycemic unawareness, and reduce the risk of death due to severe hypoglycemia. However, there are many obstacles contributing to the early mass loss of the islets and progressive islet loss in the late stages of clinical islet transplantation, including hypoxia injury, instant blood-mediated inflammatory reactions, inflammatory cytokines, immune rejection, metabolic exhaustion, and immunosuppression-related toxicity that is detrimental to the islet allograft. Here, we discuss the fate of intrahepatic islets infused through the portal vein and propose potential interventions to promote islet allograft survival and improve long-term graft function.

Isx9 Regulates Calbindin D28K Expression in Pancreatic β Cells and Promotes β Cell Survival and Function

Pancreatic β-cell dysfunction and death contribute to the onset of diabetes, and novel strategies of β-cell function and survival under diabetogenic conditions need to be explored. We previously demonstrated that Isx9, a small molecule based on the isoxazole scaffold, drives neuroendocrine phenotypes by increasing the expression of genes required for β-cell function and improves glycemia in a model of β cell regeneration. We further investigated the role of Isx9 in β-cell survival. We find that Isx9 drives the expression of Calbindin-D28K (D28K), a key regulator of calcium homeostasis, and plays a cytoprotective role through its calcium buffering capacity in β cells. Isx9 increased the activity of the calcineurin (CN)/cytoplasmic nuclear factor of the activated T-cells (NFAT) transcription factor, a key regulator of D28K, and improved the recruitment of NFATc1, cAMP response element-binding protein (CREB), and p300 to the D28K promoter. We found that nutrient stimulation increased D28K plasma membrane enrichment and modulated calcium channel activity in order to regulate glucose-induced insulin secretion. Isx9-mediated expression of D28K protected β cells against chronic stress induced by serum withdrawal or chronic inflammation by reducing caspase 3 activity. Consequently, Isx9 improved human islet function after transplantation in NOD-SCID mice in a streptozotocin-induced diabetes model. In summary, Isx9 significantly regulates expression of genes relevant to β cell survival and function, and may be an attractive therapy to treat diabetes and improve islet function post-transplantation.

β Cell replacement: improving on the design

PURPOSE OF REVIEW

Here we summarize recent advancements in β cell replacement as a therapy for type 1 diabetes.

RECENT FINDINGS

β cell replacement therapy has been proposed as a cure for type 1 diabetes with the introduction of the Edmonton protocol for cadaveric islet transplantation. To allow widespread use of this approach, efforts have focused on establishing an abundant source of insulin-producing β cells, protecting transplanted cells from ischemia-mediated death, immune rejection, and re-occurring autoimmunity. Recent developments addressing these issues include generation of insulin-producing cells from human pluripotent stem cells, different encapsulation strategies and prevention of ischemia upon transplant.

SUMMARY

Despite significant advances in generating functional β cells from human pluripotent stem cells, several key challenges remain in regard to the survival of β cell grafts, protection from (auto-) immune destruction and implementation of additional safety mechanisms before a stem cell-based cell replacement therapy approach can be widely applied. Taking current findings into consideration, we outline a multilayered approach to design immune-privileged β cells from stem cells using state of the art genome editing technologies that if successfully incorporated could result in great benefit for diabetic patients and improve clinical results for cell replacement therapy.

Posttransplant Tacrolimus-Induced Diabetic Ketoacidosis: Review of the Literature

Diabetic ketoacidosis (DKA) in patients receiving tacrolimus as part of their immunosuppressive regimen is a rarely reported adverse event. We report a patient with autosomal dominant polycystic kidney disease (ADPKD) and no known history of diabetes mellitus who presented with DKA, 3 months after kidney transplantation.

Role of FOXO1 in aldosterone-induced autophagy: a compensatory protective mechanism related to podocyte injury

This study was undertaken to elucidate whether and how autophagy was regulated in aldosterone (Aldo)-induced podocyte injury and to examine its role in this model both in vitro and in vivo. In cultured podocytes, Aldo increased autophagy flux as indicated by the enhanced expression of LC3-II/LC3-I and the reduction of p62. Autophagy induction with rapamycin (RP) provided a cytoprotective effect, and inhibition of autophagy with Atg7-specific siRNA, chloroquine (CQ) or 3-methyladenine (3-MA) worsened Aldo-induced podocyte injury by attenuating endoplasmic reticulum (ER) stress. Aldo inhibited Akt phosphorylation but increased the mammalian target of rapamycin (mTOR) signaling pathway; however, Aldo up-regulated the expression of FOXO1 and its downstream effector Rab7. Either knockdown of FOXO1 or Rab7 inhibited Aldo-induced autophagy. Additionally, an elevated level of P300-regulated acetylation of FOXO1 and the interaction of acetylated FOXO1 and Atg7 were also confirmed to be involved in regulating autophagy in Aldo-induced podocytes. Similar results were further confirmed in vivo. We propose that autophagy enhancement through enhancing of the FOXO1/Rab7 axis and post-translational modification of FOXO1 may represent a potential therapeutic strategy against podocyte injury by promoting autophagy.

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.

Clinical pancreatic islet transplantation

Clinical pancreatic islet transplantation can be considered one of the safest and least invasive transplant procedures. Remarkable progress has occurred in both the technical aspects of islet cell processing and the outcomes of clinical islet transplantation. With >1,500 patients treated since 2000, this therapeutic strategy has moved from a curiosity to a realistic treatment option for selected patients with type 1 diabetes mellitus (that is, those with hypoglycaemia unawareness, severe hypoglycaemic episodes and glycaemic lability). This Review outlines the techniques required for human islet isolation, in vitro culture before the transplant and clinical islet transplantation, and discusses indications, optimization of recipient immunosuppression and management of adjunctive immunomodulatory and anti-inflammatory strategies. The potential risks, long-term outcomes and advances in treatment after the transplant are also discussed to further move this treatment towards becoming a more widely available option for patients with type 1 diabetes mellitus and eventually a potential cure.

Hyperglycaemic hyperosmolar syndrome in children: Patient characteristics, diagnostic delays and associated complications

AIMS

The aim of this study was to describe the demographical and clinical characteristics, diagnostic difficulties, and morbidity and mortality in children with hyperglycaemic hyperosmolar syndrome (HHS).

METHODS

Retrospective cross-section descriptive study of children (<18 years of age) at an urban, tertiary, academic Children's Hospital diagnosed with HHS from January 2002 to December 2011.

RESULTS

Six patients met inclusion criteria for the diagnosis of HHS. Age ranged from 6 to 16 years with 4 (67%) patients younger than 13 years. Four (67%) patients were women and 5 (83%) were African-American. Body mass index (BMI)-for-age percentile was >97% in four (67%) patients. Three (60%) of five patients seen as outpatients were misdiagnosed, two cases were seen twice before an accurate diagnosis of HHS was made. There was one (17%) death. Complications included three patients with acute renal failure, one patient with seizures, and one patient with rhabdomyolysis and compartment syndrome leading to below the knee amputation. Malignant hyperthermia and ventricular arrhythmias occurred in the patient who expired. Three of the five patients who had autoantibody tests had positive results and were diagnosed with type 1 diabetes mellitus.

CONCLUSIONS

Characteristics of children with HSS are variable for age, gender and BMI-for-age percentile and not predominately limited to obese male adolescent African-American. Delay in diagnosis is common and morbidity and mortality in paediatric HHS are significant. The subsequent diagnosis of patients presenting with HHS includes type 1 and 2 diabetes mellitus.

Tacrolimus-Induced Diabetic Ketoacidosis After Allogeneic Bone Marrow Transplant

New-onset diabetes mellitus after solid-organ transplant makes for complicated tacrolimus immunosuppression. However, tacrolimus-associated diabetic ketoacidosis has not been reported in bone marrow transplant. We report 24-year-old women, hospitalized with diabetic ketoacidosis, 70 days after undergoing a bone marrow transplant with tacrolimus immunosuppression. Clinicians should be wary about tacrolimus levels and the risk of hyperglycemic states after bone marrow transplant as with other solid-organ transplants.

Effect of Chronic Administration of Low Dose Rapamycin on Development and Immunity in Young Rats

Mammalian target of rapamycin (mTOR) regulates cell growth, cell differentiation and protein synthesis. Rapamycin, an inhibitor of mTOR, has been widely used as an immunosuppressant and anti-cancer drug. Recently, mTOR inhibitors have also been reported to be a potential anti-epileptic drug, which may be effective when used in young patients with genetic epilepsy. Thus, a suitable dose of rapamycin which can maintain the normal function of mTOR and has fewer side effects ideally should be identified. In the present study, we first detected changes in marker proteins of mTOR signaling pathway during development. Then we determined the dose of rapamycin by treating rats of 2 weeks of age with different doses of rapamycin for 3 days and detected its effect on mTOR pathway. Young rats were then treated with a suitable dose of rapamycin for 4 weeks and the effect of rapamycin on mTOR, development and immunity were investigated. We found that the expression of the marker proteins of mTOR pathway was changed during development in brain hippocampus and neocortex. After 3 days of treanent, 0.03 mg/kg rapamycin had no effect on phospho-S6, whereas 0.1, 0.3, 1.0 and 3.0 mg/kg rapamycin inhibited phospho-S6 in a dose-dependent manner. However, only 1.0 mg/kg and 3.0 mg/kg rapamycin inhibited phospho-S6 after 4 weeks treatment of rapamycin. Parallel to this result, rats treated with 0.1 and 0.3 mg/kg rapamycin had no obvious adverse effects, whereas rats treated with 1.0 and 3.0 mg/kg rapamycin showed significant decreases in body, spleen and thymus weight. Additionally, rats treated with 1.0 and 3.0 mg/kg rapamycin exhibited cognitive impairment and anxiety as evident by maze and open field experiments. Furthermore, the content of IL-1β, IL-2, IFN-γ, TNF-α in serum and cerebral cortex were significantly decreased in 1.0 and 3.0 mg/kg rapamycin-treated rats. The expression of DCX was also significantly decreased in 1.0 and 3.0 mg/kg rapamycin-treated rats. However, rats treated with 1.0 mg/ kg rapamycin exhibited fewer and milder side effects than those treated with 3.0 mg/kg. In summary, all these data suggest that there is not a rapamycin dose that can inhibit mTOR for epilepsy without causing any side effects, but 1 mg /kg may be the optimal dose for young rats for suppressing mTOR with relatively few side effects.