Sirolimus and everolimus in kidney transplantation

LPM electrode loaded with RAPA-PLGA drug sustained-release system can reduce local fibrous tissue hyperplasia and local bioelectrical impedance

OBJECTIVE

This study aims to design and fabricate a leadless pacemaker (LPM) electrode loaded with rapamycin (RAPA)-poly(lactic-co-glycolic acid) (PLGA) drug sustained-release system to reduce the local fibrous tissue proliferation after LPM implantation, reduce local bioelectrical impedance, and facilitate the safe extraction of LPM after use.

METHODS

We fabricated an LPM electrode loaded with the RAPA-PLGA drug-sustained-release system and carried out in vitro and in vivo experiments to verify its effect.

RESULTS

A scanning electron microscope showed that the LPM electrode cavity was loaded with the RAPA-PLGA drug's sustained-release system. The energy-dispersive spectrometer showed that the LPM electrode had RAPA and PLGA-related elements. The average drug loading rate of the drug sustained-release system was (51.02% ± 2.66) %, and the encapsulation rate was (85.04% ± 4.43%). The RAPA loaded in the electrode chamber was about (337.83 ± 53.66)μg. In vitro release results show that the LPM electrode loaded with RAPA-PLGA can continue to release for 44 days. In vitro cell inhibition experiments showed that the drug-loaded electrode group had an obvious inhibitory effect on fibroblasts, and the difference between the groups was significant (p < 0.05). In vivo experiments showed that the local bioelectrical impedance of the drug-loaded electrode group is lower than that of the control group, with a difference between groups with statistical significance (p < 0.05). The histopathological analysis of tissue sections from the site of (LPM electrode implantation revealed reduced fibrous tissue hyperplasia in the drug-loaded electrode group compared to the control group. Additionally, H&E staining indicated that the implantation of drug-loaded electrodes did not induce abnormal alterations in the liver, heart, spleen, lung, or kidney tissues.

CONCLUSION

The LPM electrode loaded with RAPA-PLGA demonstrates significant, sustained drug release and anti-proliferative effects in vitro. This drug-loaded electrode has been deemed safe for implantation in animal models. It can effectively inhibit local fibrous tissue proliferation and reduce local bioelectrical impedance, offering a technical strategy to prolong the in vivo functionality of LPMs and enhance clinical procedures.

Everolimus Personalized Therapy: Second Consensus Report by the International Association of Therapeutic Drug Monitoring and Clinical Toxicology

ABSTRACT

The Immunosuppressive Drugs Scientific Committee of the International Association of Therapeutic Drug Monitoring and Clinical Toxicology established the second consensus report to guide therapeutic drug monitoring (TDM) of everolimus (EVR) and its optimal use in clinical practice 7 years after the first version was published in 2016. This version provides information focused on new developments that have arisen in the last 7 years. For the general aspects of the pharmacology and TDM of EVR that have retained their relevance, readers can refer to the 2016 document. This edition includes new evidence from the literature, focusing on the topics updated during the last 7 years, including indirect pharmacological effects of EVR on the mammalian target of rapamycin complex 2 with the major mechanism of direct inhibition of the mammalian target of rapamycin complex 1. In addition, various concepts and technical options to monitor EVR concentrations, improve analytical performance, and increase the number of options available for immunochemical analytical methods have been included. Only limited new pharmacogenetic information regarding EVR has emerged; however, pharmacometrics and model-informed precision dosing have been constructed using physiological parameters as covariates, including pharmacogenetic information. In clinical settings, EVR is combined with a decreased dose of calcineurin inhibitors, such as tacrolimus and cyclosporine, instead of mycophenolic acid. The literature and recommendations for specific organ transplantations, such as that of the kidneys, liver, heart, and lungs, as well as for oncology and pediatrics have been updated. EVR TDM for pancreatic and islet transplantation has been added to this edition. The pharmacodynamic monitoring of EVR in organ transplantation has also been updated. These updates and additions, along with the previous version of this consensus document, will be helpful to clinicians and researchers treating patients receiving EVR.

Sirolimus reduces T cell cycling, immune checkpoint marker expression, and HIV-1 DNA in people with HIV

Key HIV cure strategies involve reversing immune dysfunction and limiting the proliferation of infected T cells. We evaluate the safety of sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, in people with HIV (PWH) and study the impact of sirolimus on HIV-1 reservoir size and HIV-1-specific immunity in a single-arm study of 20 weeks of treatment in PWH on antiretroviral therapy (ART). Sirolimus treatment does not impact HIV-1-specific CD8 T cell responses but leads to a significant decrease in CD4+ T cell-associated HIV-1 DNA levels at 20 weeks of therapy in the primary efficacy population (n = 16; 31% decline, p = 0.008). This decline persists for at least 12 weeks following cessation of the study drug. Sirolimus treatment also leads to a significant reduction in CD4+ T cell cycling and PD-1 expression on CD8+ lymphocytes. These data suggest that homeostatic proliferation of infected cells, an important mechanism for HIV persistence, is an intriguing therapeutic target.

Immunosuppressant therapy averts rejection of allogeneic FKBP1A-disrupted CAR-T cells

Chimeric antigen receptor (CAR) T cells from allogeneic donors promise "off-the-shelf" availability by overcoming challenges associated with autologous cell manufacturing. However, recipient immunologic rejection of allogeneic CAR-T cells may decrease their in vivo lifespan and limit treatment efficacy. Here, we demonstrate that the immunosuppressants rapamycin and tacrolimus effectively mitigate allorejection of HLA-mismatched CAR-T cells in immunocompetent humanized mice, extending their in vivo persistence to that of syngeneic humanized mouse-derived CAR-T cells. In turn, genetic knockout (KO) of FKBP prolyl isomerase 1A (FKBP1A), which encodes a protein targeted by both drugs, was necessary to confer CD19-specific CAR-T cells (19CAR) robust functional resistance to these immunosuppressants. FKBP1AKO 19CAR-T cells maintained potent in vitro functional profiles and controlled in vivo tumor progression similarly to untreated 19CAR-T cells. Moreover, immunosuppressant treatment averted in vivo allorejection permitting FKBP1AKO 19CAR-T cell-driven B cell aplasia. Thus, we demonstrate that genome engineering enables immunosuppressant treatment to improve the therapeutic potential of universal donor-derived CAR-T cells.

Therapeutic Drug Monitoring for Sirolimus in Children with Vascular Anomalies: What Can We Learn from a Retrospective Study

Objectives: Sirolimus (SRL), a mammalian target of rapamycin inhibitor, has been widely used to treat patients with vascular anomalies (VAs). The objectives of this study were to summarize the routine blood SRL monitoring data for VAs children, to investigate the factors contributing to the variable blood SRL concentrations and to evaluate the efficacy and safety of SRL therapy. Methods: VAs patients with routine blood SRL monitoring from July 2017 to April 2022 at the Department of Burns and Plastic Surgery, Children's Hospital of Nanjing Medical University were retrospectively collected. Clinical data were obtained from the hospital information system. Results: In total, 67 children (35 females) were enrolled. The therapeutic drug monitoring data showed that the range of measured blood trough concentrations (Ctrough) was 3.6-46.8 ng/mL. At the initial measurements, only 33% of patients were in the target concentration range (10-15 ng/mL). But this proportion became 54% at the last measurements. The whole blood-Ctrough-to-daily dose (Ctrough/Dose) ratio was significantly associated with age and body weight (BW). The patients' laboratory results did not change significantly after SRL treatment. Although the incidence of adverse events was relatively high (44.8%), most of them were mild and tolerable. 70.3% patients had total responses to SRL, whereas 29.7% children exhibited stable disease or progressive disease. No significant differences were found in Ctrough between the total response group and non-response group. Conclusions: This retrospective study revealed a high variability in SRL blood concentrations in Chinese children with VAs. Of note, pediatric patients with older age and a higher BW had a lower Ctrough/Dose ratio. It is a concern whether the range of 10-15 ng/mL is feasible for Chinese children based only on our study. Further studies recruiting more patients are required to redefine the target reference range for children with VAs.

Population pharmacokinetic study in children with vascular anomalies: body weight as a key variable in predicting the initial dose and dosing frequency of sirolimus

Background

The main challenges faced when using sirolimus in children with vascular anomalies (VAs) still include significant pharmacokinetic (PK) variability, uncertainty in the target concentration range, as well as inconsistencies in initial dosing and dosing frequency. The aim of this study is to establish a new population pharmacokinetic (PPK) model for children with VAs to guide the individualized use of sirolimus.

Methods

A PPK study was performed using data from children with VAs who received sirolimus between July 2017 and April 2022. A nonlinear mixed-effect modeling with a one-compartment model structure was applied. Monte Carlo simulation was employed to propose specific dosing recommendations to achieve the target trough concentrations (C trough) of 5-15 ng/mL.

Results

In total, 134 blood concentrations from 49 pediatric patients were used to characterize the sirolimus pharmacokinetics. Covariate analysis identified body weight (BW) as a significant factor affecting clearance (CL) in the final PPK model. The typical clearance rate and distribution volume, standardized to a BW of 16 kg, were 4.06 L/h (4% relative standard error, RSE) and 155 L (26% RSE), respectively. Optimal dosing regimens were simulated for different BWs. For a twice-daily regimen, the recommended doses were 0.05, 0.06, 0.07, and 0.08 mg/kg/day for BW of <10, 10-20, 20-40, and ≥40 kg, respectively; for a once-daily regimen, the recommended doses were 0.06, 0.07, 0.08, and 0.09 mg/kg/day for BW of <10, 10-30, 30-50, and ≥50 kg, respectively. Notably, sirolimus C trough could be maintained between 5-15 ng/mL across various dosing frequencies based on the recommended dosing regimen.

Conclusion

We established a PPK model of sirolimus for children with VAs and proposed an initial dosing strategy. Integrating initial dose and medication frequency recommendations into sirolimus' guidelines will broaden its clinical options and simplify the clinical management for childhood VAs.

Coronavirus Disease 2019 in Kidney Transplantation - A 2024 Update

The coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 has led to the death of about 7 million people worldwide. When infected, older individuals and those with diabetes, hypertension, cardiovascular disease, and compromised immune system are at higher risk for unfavorable outcomes. These comorbidities are prevalent in kidney transplant candidates and recipients making them inherently vulnerable to severe acute respiratory syndrome coronavirus 2 infection, hence, the significant burden the pandemic has exerted on kidney transplant programs. With the swift discovery and wide-scale availability of vaccines and therapeutics against severe acute respiratory syndrome coronavirus 2, the pandemic is currently behind us allowing transplant programs to relieve their restrictions and resume normal pre-COVID-19 operations. In the aftermath of the pandemic, we discuss the implications for immunosuppression and vaccination, COVID-19-induced kidney injury phenotypes and long COVID-19 symptoms. We also discuss some of the operational aspects the pandemic brought about - mainly the utilization of telemedicine - that are now here to stay.

Update on Maintenance Immunosuppression in Intestinal Transplantation

Outcomes in intestinal transplantation remain hampered by higher rates of rejection than any other solid organs. However, maintenance immunosuppression regimens have largely remained unchanged despite advances in therapies for induction and treatment of rejection and graft-versus-host disease. Recently, there have been a small number of new maintenance therapies attempted, and older agents have been used in new ways to achieve better outcomes. The authors herein review the traditional maintenance therapies and their mechanisms and then consider updates in new therapies and new ways of using old therapies for maintenance immunosuppression after intestinal transplantation.

Pharmacodynamic Effect of mTOR Inhibition-based Immunosuppressive Therapy on T- and B-cell Subsets After Renal Transplantation

Background

The mammalian target of rapamycin inhibitor (mTORi) therapy after kidney transplantation is solely monitored pharmacokinetically, not necessarily reflecting PI3K-Akt-mTOR pathway blockade efficacy leading to potential under-or overimmunosuppression.

Methods

In this cross-sectional study, phosphoflow cytometry was used to determine the efficacy of mTOR inhibition in peripheral T- and B-lymphocyte subsets by assessing p70S6 kinase (p70S6K) phosphorylation in renal transplant recipients upon treatment with a combination of either mTORi and calcineurin inhibitors (n = 18), or mTORi with mycophenolic acid (n = 9). Nine dialysis patients with end-stage renal disease and 17 healthy age-matched volunteers served as controls.

Results

mTORi treatment reduced p70S6K phosphorylation in CD4+, CD8+ T, and CD19+ B cells compared with healthy controls (HCs). Subpopulation analysis of CD4+ T cells and CD19+ B cells revealed a significant reduction of p70S6K phosphorylation in CD4+CD45RA-CD25- Th cells (P < 0.05), CD24hiCD38hi transitional B cells (P < 0.001), CD24+CD38- memory B cells (P < 0.001), and CD24intCD38int-naive B cells (P < 0.05) upon mTORi treatment, whereas CD4+CD45RA-CD25++CD127- regulatory T cells and CD24-CD38hi plasmablasts were not affected. Compared with mTORi + mycophenolic acid therapy, mTORi + calcineurin inhibitor treatment exhibited an even stronger inhibition of p70S6K phosphorylation in CD4+CD45RA-CD25- Th cells and CD8+ T cells. However, trough levels of mTORi did not correlate with p70S6K phosphorylation.

Conclusions

mTORi selectively inhibited p70S6K phosphorylation in select lymphocyte subtypes. Assessing p70S6K phosphorylation by phosphoflow cytometry may serve as an approach to understand cell subset specific effects of mTORi providing detailed pharmacodynamic information for individualizing immunosuppression.

Cardiac Rhabdomyomas Presenting with Critical Cardiac Obstruction in Neonates and Infants: Treatment Strategies and Outcome, A Single-Center Experience

Cardiac rhabdomyomas are the most common benign pediatric heart tumor in infancy, which are commonly associated with tuberous sclerosis complex (TSC). Most rhabdomyomas are asymptomatic and spontaneously regress over time. However, some cases especially in neonates or small infants can present with hemodynamic instability. Surgical resection of the tumor, which has been the gold standard in alleviating obstruction, is not always possible and may be associated with significant morbidity and mortality. Recently, mammalian target of rapamycin inhibitors (mTORi) have been shown to be safe and effective in the treatment of TSC. We present the outcomes of neonates and an infant who received treatment for symptomatic rhabdomyomas at a tertiary cardiology center. Medical records were reviewed to obtain clinical, demographic, and outcome data. Six patients received interventions for symptomatic rhabdomyomas, median age at presentation was 1 day old (range from 1 to 121 days old), and 67% of the patients had a pathogenic mutation in TSC gene. One patient underwent surgical resection of solitary tumor at right ventricular outflow tract (RVOT) successfully. In the four patients with left ventricular outflow tract (LVOT) obstruction, two patients received combined therapy of surgical debulking of LVOT tumor, Stage I palliation procedure, and mTORi and two patients received mTORi therapy. One patient with RVOT obstruction underwent ductal stenting and received synergistic mTORi. Four of the five patients had good response to mTORi demonstrated by the rapid regression of rhabdomyoma size. 83% of patients are still alive at their latest follow-up, at two to eight years of age. One patient died on day 17 post-LVOT tumor resection and Hybrid stage one due to failure of hemostasis, in the background of familial factor VII deficiency. Treatment of symptomatic rhabdomyoma requires individualized treatment strategy based on the underlying pathophysiology, with involvement of multidisciplinary teams. mTORi is effective and safe in inducing rapid regression of rhabdomyomas. A standardized mTORi prescription and monitoring guide will ensure medication safety in neonates and infants with symptomatic cardiac rhabdomyoma. Although the majority of tumors responded to mTORi, some prove to be resistant. Further studies are warranted, ideally involving multiple international centers with a larger number of patients.

Evaluating the effect of rapamycin treatment in Alzheimer's disease and aging using in vivo imaging: the ERAP phase IIa clinical study protocol

BACKGROUND

Rapamycin is an inhibitor of the mechanistic target of rapamycin (mTOR) protein kinase, and preclinical data demonstrate that it is a promising candidate for a general gero- and neuroprotective treatment in humans. Results from mouse models of Alzheimer's disease have shown beneficial effects of rapamycin, including preventing or reversing cognitive deficits, reducing amyloid oligomers and tauopathies and normalizing synaptic plasticity and cerebral glucose uptake. The "Evaluating Rapamycin Treatment in Alzheimer's Disease using Positron Emission Tomography" (ERAP) trial aims to test if these results translate to humans through evaluating the change in cerebral glucose uptake following six months of rapamycin treatment in participants with early-stage Alzheimer's disease.

METHODS

ERAP is a six-month-long, single-arm, open-label, phase IIa biomarker-driven study evaluating if the drug rapamycin can be repurposed to treat Alzheimer's disease. Fifteen patients will be included and treated with a weekly dose of 7 mg rapamycin for six months. The primary endpoint will be change in cerebral glucose uptake, measured using [18F]FDG positron emission tomography. Secondary endpoints include changes in cognitive measures, markers in cerebrospinal fluid as well as cerebral blood flow measured using magnetic resonance imaging. As exploratory outcomes, the study will assess change in multiple age-related pathological processes, such as periodontal inflammation, retinal degeneration, bone mineral density loss, atherosclerosis and decreased cardiac function.

DISCUSSION

The ERAP study is a clinical trial using in vivo imaging biomarkers to assess the repurposing of rapamycin for the treatment of Alzheimer's disease. If successful, the study would provide a strong rationale for large-scale evaluation of mTOR-inhibitors as a potential disease-modifying treatment in Alzheimer's disease.

TRIAL REGISTRATION

ClinicalTrials.gov ID NCT06022068, date of registration 2023-08-30.

Sirolimus-induced Hypertriglyceridemia Leads to Acute Pancreatitis and Diabetic Ketoacidosis Post Stem Cell Transplant for Sickle Cell Disease

Sirolimus (mammalian target of rapamycin inhibitor) is a potent immunosuppressive agent, used in patients receiving hematopoietic stem cell transplant (HSCT) for Graft vs Host disease prophylaxis. Compared to calcineurin inhibitors, sirolimus has no neurotoxicity or nephrotoxicity, but sirolimus causes dose-dependent thrombocytopenia, leukopenia, delayed wound healing, hyperlipidemia, and hypertriglyceridemia. Here we report a case of acute pancreatitis and diabetic ketoacidosis in a patient with sickle cell disease post haploidentical family donor HSCT which was managed conservatively without plasmapheresis. Based on our review of the literature, this is the first reported case of developing acute pancreatitis as an adverse effect of sirolimus-induced hypertriglyceridemia leading to diabetic ketoacidosis in a recipient of HSCT.

mTORC1 Signaling and Negative Lens-Induced Axial Elongation

Purpose

The mechanism underlying axial elongation during myopia progression remains unknown. Epidermal growth factor receptor (EGFR) signaling is associated with axial elongation. We explored whether mammalian target of rapamycin complex 1 (mTORC1) signaling acts as the downstream pathway of EGFR and participates in negative lens-induced axial elongation (NLIAE).

Methods

Three-week-old male pigmented guinea pigs underwent binocular NLIAE. (1) To investigate whether EGFR is the upstream regulator of mTORC1, an EGFR inhibitor (20 µg erlotinib) was intravitreally injected once a week for three weeks. (2) To assess the effect of mTORC1 inhibition on NLIAE, an mTORC1 inhibitor (2 µg, 10 µg, and 20 µg everolimus) was intravitreally injected once a week for three weeks. (3) To explore the long-term effect of mTORC1 overactivation on axial elongation, an mTORC1 agonist (4 µg MHY1485) was intravitreally injected once a week for three months. Biometric measurements included axial length and choroidal thickness were performed.

Results

Compared with the guinea pigs without NLIAE, NLIAE was associated with activation of mTORC1 signaling, which was suppressed by intravitreal erlotinib injection. Intravitreally injected everolimus suppressed NLIAE-induced axial elongation, mTORC1 activation, choroidal thinning, and hypoxia-inducible factor-1α expression in the sclera. Immunofluorescence revealed that the retinal pigment epithelium was the primary location of mTORC1 activation during NLIAE. Combining NLIAE and MHY1485 intravitreal injections significantly promoted axial elongation, choroidal thinning, and peripapillary choroidal atrophy.

Conclusions

The mTORC1 signaling is associated with increased axial elongation, as in NLIAE, raising the possibility of inhibiting mTORC1 as a novel treatment for slowing myopia progression.

The Value of Klotho in Kidney Transplantation

Kidney transplant recipients have better survival rates and improved quality of life than long-term dialysis patients. However, delayed graft function, immunosuppressive therapy nephrotoxicity, and rejection episodes may compromise graft and patient survival. The KL gene is highly expressed in kidney tubular cells and encodes the antiaging and kidney-protective protein Klotho, which has membrane-anchored and soluble forms and regulates mineral metabolism. Klotho expression decreases during acute kidney injury or chronic kidney disease, and human chronic kidney disease shares features of accelerated aging with murine Klotho deficiency. In this work, we review clinical studies on the relationship between Klotho and kidney transplantation. Specifically, we address the dynamics of serum and kidney Klotho levels in donors and kidney transplant recipients, the role of Klotho as a marker of current graft function and graft outcomes, and the potential impact of Klotho on kidney protection in the transplantation context. A better understanding of the potential biomarker and therapeutic utility of Klotho in kidney transplant recipients may provide new insights into the control of graft function and new therapeutic strategies to preserve allograft function.

Development of UHPLC-MS/MS method for simultaneous determination of tacrolimus and sirolimus in human whole blood and comparisons with two immunoassays

Tacrolimus (TAC) and sirolimus (SIR) antirejection medications are widely used in organ transplantation. We aimed to develop an ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) assay for quantifying TAC and SIR simultaneously and evaluating agreement with chemiluminescence microparticle immunoassay (CMIA) and electrochemiluminescence immunoassay (ECLIA). Whole blood samples collected from 209 TAC and 208 SIR patients were assessed by UHPLC-MS/MS, CMIA and ECLIA. The agreement of the three techniques was assessed using the Bland-Altman plot. The UHPLC-MS/MS assay had a calibration range of 1-100 ng/ml for TAC and SIR. The accuracy and precision were -2.73-4.32% and <4.71% for TAC, respectively, and 0.07-4.84% and <6.5% for SIR, respectively. The three methods had good correlation. In comparison with UHPLC-MS/MS, two immunoassays showed a slight deviation in proportion. An UHPLC-MS/MS method for simultaneously detecting TAC and SIR in human whole blood was developed, validated and comparatively analyzed with CMIA and ECLIA. For determining TAC and SIR, immunoassays displayed acceptable analytical performances in terms of precision and correlation compared with UHPLC-MS/MS. However, further investigation is warranted to examine the novel method.

Pharmacokinetic principles of dose adjustment of mTOR inhibitors in solid organ transplanted patients

WHAT IS KNOWN AND OBJECTIVES

mTOR inhibitors possess narrow therapeutic range and substantial pharmacokinetic variability and the consequences from suboptimal dosing are serious. The aim of this review is to summarize the current knowledge about the factors influencing mTOR inhibitors pharmacokinetics and the possibility of using these relationships in order to improve its therapy individualization in solid organ transplanted patients.

METHODS

Literature search from Pubmed and Web of Science databases were performed using Boolean search operators in order to identify relevant studies.

RESULTS AND DISCUSSION

A total of 701 reports were identified from the initial literature search. Out of which 40 studies dealt with relationships between various factors and pharmacokinetics of mTOR inhibitors and with relevance of these associations for dosage optimization.

WHAT IS NEW AND CONCLUSION

The overview of the current covariates for pharmacokinetic variability of mTOR inhibitors has been provided on the level of absorption, distribution and elimination, and consequences of these relationships for dosing optimization has been summarized.

Population Pharmacokinetic Analysis and Dosing Optimization of Sirolimus in Children With Tuberous Sclerosis Complex

Sirolimus is confirmed to be effective in the treatment of tuberous sclerosis complex (TSC) and related disorders. The study aims to establish a population pharmacokinetic model of oral sirolimus for children with TSC and provide an evidence-based approach for individualization of sirolimus dosing in the pediatric population. A total of 64 children were recruited in this multicenter, retrospective pharmacokinetic study. Whole-blood concentrations of sirolimus, demographic, and clinical information were collected and analyzed using a nonlinear mixed-effects population modeling method. The final model was internally and externally validated. Then Monte Carlo simulations were performed to evaluate and optimize the dosing regimens. In addition, the efficacy and safety of sirolimus therapy was assessed retrospectively in patients with epilepsy or cardiac rhabdomyomas associated with TSC. Finally, the sirolimus pharmacokinetic profile was described by a 1-compartment model with first-order absorption and elimination along with body weight and total daily dose as significant covariates. The typical population parameter estimates of apparent volume of distribution and apparent clearance were 69.48 L and 2.79 L/h, respectively. Simulations demonstrated that dosage regimens stratified by body surface area may be more appropriate for children with TSC. These findings could be used to inform individualized dosing strategies of sirolimus for pediatric patients with TSC.

Proposals for a standardized procedure of validation of DNA extraction and allelic discrimination assays in pharmacogenomics according to ISO15189 requirements

OBJECTIVES

In the era of quality management in clinical laboratories, method validation can be a challenge without appropriate guidelines, such as in the field of pharmacogenetics. The present work describes a method validation for DNA extraction and CYP3A5*3 genotyping, which would meet ISO15189:2012 requirements.

METHODS

DNA extraction was performed using a QIAamp DSP DNA Blood kit, DNA purity and concentration were determined using a Nanodrop, and the genotyping assay was a real-rime PCR using TaqMan reagents. Validation criteria were similar to those usually verified when validating methods in the analytical field: specificity, sensitivity, cross-over contamination, stability of reagents, robustness, lower and upper limits of detection, and between-run and within-run precisions. A comparison to alternate or reference methods was also performed (i.e. QiAamp kit versus DNA extractor and TaqMan genotyping versus Sanger sequencing). Each validation step is described from the pharmacogenetic point of view, as well as acceptance criteria for both DNA extraction [i.e. concentration relative SD (RSD) below 25%, verified purity, and no DNA in blank samples] and genotyping assay (i.e. specificity and diagnostic sensitivity, RSD of mean threshold cycle below 15%, no amplification in blank samples).

RESULTS

Concerning CYP3A5 genotyping following a DNA extraction described as an example, validation criteria were met, allowing routine use of this analytical process. Cost estimation of the overall validation procedure was approximately 290 euros, concerning reagents and consumables.

CONCLUSION

This work aims to provide a reference for method validation for pharmacogenetic analysis using real-time PCR to detect single nucleotide polymorphisms, in accordance with ISO15189:2012.

Mammalian Target of Rapamycin Inhibitors and Wound Healing Complications in Kidney Transplantation: Old Myths and New Realities

Mammalian target of rapamycin inhibitors (mTOR-I) lacks nephrotoxicity, has antineoplastic effects, and reduces viral infections in kidney transplant recipients. Earlier studies reported a significant incidence of wound healing complications and lymphocele. This resulted in the uncomfortable willingness of transplant clinicians to use these agents in the immediate posttransplant period. As evidence and experience evolved over time, much useful information became available about the optimal use of these agents. Understandably, mTOR-I effects wound healing through their antiproliferative properties. However, there are a lot of other immunological and nonimmunological factors which can also contribute to wound healing complications. These risk factors include obesity, uremia, increasing age, diabetes, smoking, alcoholism, and protein-energy malnutrition. Except for age, the rest of all these risk factors are modifiable. At the same time, mycophenolic acid derivatives, steroids, and antithymocyte globulin (ATG) have also been implicated in wound healing complications. A lot has been learnt about the optimal dose of mTOR-I and their trough levels, its combinations with other immunosuppressive medications, and patients' profile, enabling clinicians to use these agents appropriately for maximum benefits. Recent randomized control trials have further increased the confidence of clinicians to use these agents in immediate posttransplant periods.

Population pharmacokinetics of sirolimus in Chinese adult liver transplant recipients: a retrospective study

Considering the significant interindividual variability and a narrow therapeutic index, we aimed to determine the population pharmacokinetics (PPK) of sirolimus and identify the factors in Chinese adult liver transplant recipients.Data were retrospectively extracted from adult liver transplant recipients receiving sirolimus in our hospital. The trough blood concentration data, obtained from traditional therapeutic drug monitoring-based dose adjustments, were used to develop a population pharmacokinetic model by non-linear mixed-effects modelling (NONMEM). The effect of demographic features, biological characteristics and concomitant medications was measured. The final model was verified by visual prediction check (VPC), bootstrap, and simulation.One hundred and sixteen blood concentrations from 63 patients were analysed. The PPK of sirolimus could be described by a one-compartment model with first-order absorption. Covariate analysis indicated that voriconazole co-therapy significantly decreased the oral clearance (CL) of sirolimus. The results of VPC and Bootstrap demonstrated that the final pharmacokinetic model adequately predicted observed concentrations. The simulation results showed that the dosage regimen of sirolimus should be reduced to 0.25 ∼ 0.45 mg/day for adult liver transplant recipients co-administered with voriconazole. The present study developed and validated a sirolimus PPK model for Chinese adult liver transplant recipients, and voriconazole co-therapy was found to be a significant covariate in the model. These results provide important information for clinicians to optimise the treatment regimens of sirolimus in Chinese adult liver transplant recipients.

Immunosuppressive Drugs

Immunosuppressant is a class of medicines that inhibit or decrease the intensity of the immune response in the body. Most of these medications are used to allow the body less likely to resist a transplanted organ. In solid organ transplantation, immunosuppressive agents are needed for the activation of early-stage immunosuppression, the management of late-stage immunosuppression or for the maintenance of organ rejection. The emergence of novel agents and improvements in immunosuppression regimens after transplantation are significant factors leading to this progress. However, these drugs also increase the risk of infection, cancers and specific adverse side effects specific to each agent in patients particularly in pregnant women and fertility issues. Corona virus disease being hot topic of debate is has given positive outcome to immunosuppressive drugs however need more attention in future. Transplant centers across the world utilize multiple immunosuppression protocols; nevertheless, each patient can require an individually formulated immunosuppression regimen to manage the advantages and possible damage of treatment thus eliminating the likelihood of their primary disease recurrence.

Adoptive Cell Transfer of Allogeneic Epstein–Barr Virus-Specific T Lymphocytes for Treatment of Refractory EBV-Associated Posttransplant Smooth Muscle Tumors: A Case Report

Posttransplant smooth muscle tumors (PTSMTs) are rare Epstein–Barr virus (EBV)-associated neoplasms, mostly occurring after solid organ transplantation. Current therapeutic strategies include surgery and reduction of immunosuppressive medication. We describe for the first time a novel treatment approach for PTSMT by adoptive cell transfer (ACT) of EBV-specific T cells to a 20-year-old patient with a medical history of cardiac transplantation, posttransplant lymphoproliferative disease, and multilocular PTSMT. During ACT, mild cytokine release syndrome occurred, while no unexpected safety signals were recorded. We observed in vivo expansion of EBV-specific T cells and reduction of EBV viremia. Best response was stable disease after 4 months with reduction of EBV viremia and normalization of lactate dehydrogenase levels. ACT with EBV-specific T cells may be a safe and efficacious therapeutic option for PTSMT that warrants further exploration.

Preclinical evidence to support repurposing everolimus for craving reduction during protracted drug withdrawal

Cue-elicited drug-craving is a cardinal feature of addiction that intensifies (incubates) during protracted withdrawal. In a rat model, these addiction-related behavioral pathologies are mediated, respectively, by time-dependent increases in PI3K/Akt1 signaling and reduced Group 1 metabotropic glutamate receptor (mGlu) expression, within the ventromedial prefrontal cortex (vmPFC). Herein, we examined the capacity of single oral dosing with everolimus, an FDA-approved inhibitor of the PI3K/Akt effector mTOR, to reduce incubated cocaine-craving and reverse incubation-associated changes in vmPFC kinase activity and mGlu expression. Rats were trained to lever-press for intravenous infusions of cocaine or delivery of sucrose pellets and then subjected to tests for cue-reinforced responding during early (3 days) or late (30-46 days) withdrawal. Rats were gavage-infused with everolimus (0-1.0 mg/kg), either prior to testing to examine for effects upon reinforcer-seeking behavior, or immediately following testing to probe effects upon the consolidation of extinction learning. Single oral dosing with everolimus dose-dependently blocked cocaine-seeking during late withdrawal and the effect lasted at least 24 h. No everolimus effects were observed for cue-elicited sucrose-seeking or cocaine-seeking in early withdrawal. In addition, everolimus treatment, following initial cue-testing, reduced subsequent cue hyper-responsivity exhibited observed during late withdrawal, arguing a facilitation of extinction memory consolidation. everolimus' "anti-incubation" effect was associated with a reversal of withdrawal-induced changes in indices of PI3K/Akt1/mTOR activity, as well as Homer protein and mGlu1/5 expression, within the prelimbic (PL) subregion of the prefrontal cortex. Our results indicate mTOR inhibition as a viable strategy for interrupting heightened cocaine-craving and facilitating addiction recovery during protracted withdrawal.

Immunosuppressant Management in Renal Transplant Patients with COVID-19

The coronavirus disease 2019 (COVID-19) pandemic poses a special risk for both immunosuppressed patients, especially transplant recipients. Although the knowledge about this infection is growing, many uncertainties remain, particularly regarding the kidney. Kidney transplant recipients (KDRs) should be considered immunocompromised hosts since a potential risk for infection, comorbidity, and immunosuppression exposure exists. Additionally, the management of immunosuppressive agents in KDRs remains challenging. Potential drug interactions with immunosuppressive treatment escalated the risk of unwanted side effects. In this review, we aimed to attain an augmented awareness and improved management immunosuppressant for COVID-19 KDRs.

Polymorphisms in the CYP3A5 gene significantly affect the pharmacokinetics of sirolimus after kidney transplantation

Aim: Sirolimus (SIR) is an immunosuppressant with limitations, including a narrow treatment window, multiple adverse reactions and large differences within and among individuals. Objective: The correlation between numerous SNPs and SIR in terms of trough concentration in the early stage after kidney transplantation was analyzed. Materials & methods: A retrospective cohort study involving 69 kidney transplantation recipients was designed. Blood samples were collected to extract total DNAs, and trough SIR concentrations were measured. Logistic regression was used to analyze the association between SNPs and SIR trough concentrations. Results: At 7 days, 1 month and 3 months, the mean SIR trough concentration of patients in the CYP3A5 rs4646453-CC group was significantly higher than that in the CYP3A5 rs4646453-AA and CYP3A5 rs4646453-CA groups (p < 0.001) and CYP3A5 rs15524-AA group was significantly higher than that in the CYP3A5 rs15524-AG and CYP3A5 rs15524-GG groups (p < 0.001). Conclusion: Our study indicated that both CYP3A5 rs4646453 and CYP3A5 rs15524 had a certain influence on SIR trough concentration at 7 days, 1 month and 3 months.

What Therapeutic Regimen Will Be Optimal for Initial Clinical Trials of Pig Organ Transplantation?

We discuss what therapeutic regimen might be acceptable/successful in the first clinical trial of genetically engineered pig kidney or heart transplantation. As regimens based on a calcineurin inhibitor or CTLA4-Ig have proved unsuccessful, the regimen we administer to baboons is based on induction therapy with antithymocyte globulin, an anti-CD20 mAb (Rituximab), and cobra venom factor, with maintenance therapy based on blockade of the CD40/CD154 costimulation pathway (with an anti-CD40 mAb), with rapamycin, and a corticosteroid. An anti-inflammatory agent (etanercept) is administered for the first 2 wk, and adjuvant therapy includes prophylaxis against thrombotic complications, anemia, cytomegalovirus, and pneumocystis. Using this regimen, although antibody-mediated rejection certainly can occur, we have documented no definite evidence of an adaptive immune response to the pig xenograft. This regimen could also form the basis for the first clinical trial, except that cobra venom factor will be replaced by a clinically approved agent, for example, a C1-esterase inhibitor. However, none of the agents that block the CD40/CD154 pathway are yet approved for clinical use, and so this hurdle remains to be overcome. The role of anti-inflammatory agents remains unproven. The major difference between this suggested regimen and those used in allotransplantation is the replacement of a calcineurin inhibitor with a costimulation blockade agent, but this does not appear to increase the complications of the regimen.

Analysis of Immunosuppressant Drugs in Whole Blood by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Immunosuppressant medications help suppress the immune system response through inhibition of various checkpoints in the regulatory biochemical pathway. This is useful in prevention of organ rejection in transplantation or in the treatment of autoimmune diseases such as lupus or rheumatoid arthritis. Quantification of immunosuppressive drugs in blood is needed clinically for optimization of treatment and to avoid toxicity or unwanted side effects. Here, we describe a quantitative method to determine the concentration of cyclosprine A, tacrolimus, sirolimus, and everolimus in whole blood. This method has been used for many years clinically to support patient care. © 2020 by John Wiley & Sons, Inc.

Efficacy and safety of oral sirolimus for high-flow vascular malformations in real clinical practice

BACKGROUND

Vascular malformations are a complex pathology with few treatment options. In previously published studies, oral sirolimus (rapamycin) has shown promising results in the treatment of low-flow vascular malformations, but its usefulness in high-flow vascular malformations is controversial.

AIM

To evaluate the efficacy and safety of sirolimus for the treatment of high-flow vascular malformations in real-life practice.

METHODS

In a unit specializing in vascular anomalies, patients treated with oral sirolimus for high-flow vascular malformations were located by consulting the drug dispensations. Reviewing the electronic medical records, data on patient demographics, vascular malformation characteristics, treatments, toxicity and clinical course were collected and statistically analysed.

RESULTS

Nine patients with vascular malformations were included: eight had arteriovenous malformation and one had arteriovenous fistula. Six of these malformations were isolated while three were part of a syndrome. Sirolimus was initiated at a dosage of 1-4 mg/day to be taken as a single dose. Partial response was observed in eight of the nine patients (88.9%) with high-flow vascular malformation, while worsening was observed in the remaining patient. The treatment was well tolerated and at the most recent follow-up, five patients remained on treatment with oral sirolimus.

CONCLUSION

Our results show that oral sirolimus is a well-tolerated therapeutic option, with an excellent safety profile, which can be useful in the long-term stabilization of patients with high-flow vascular malformations. Single-daily dosage may improve long-term adherence to treatment without worsening its effectiveness.

Model-informed precision dosing to optimise immunosuppressive therapy in renal transplantation

Immunosuppressive therapy is pivotal for sustained allograft and patient survival after renal transplantation. However, optimally balanced immunosuppressive therapy is challenged by between-patient and within-patient pharmacokinetic (PK) variability. This could warrant the application of personalised dosing strategies to optimise individual patient outcomes. Pharmacometrics, the science that investigates the xenobiotic-biotic interplay using computer-aided mathematical modelling, provides options to describe and quantify this PK variability and enables identification of patient characteristics affecting immunosuppressant PK and treatment outcomes. Here, we review and critically appraise the available pharmacometric model-informed dosing solutions for the typical immunosuppressants in modern renal transplantation, to guide their initial and subsequent dosing.

Significance of Ethnic Factors in Immunosuppressive Therapy Management After Organ Transplantation

Clinical outcomes after organ transplantation have greatly improved in the past 2 decades with the discovery and development of immunosuppressive drugs such as calcineurin inhibitors, antiproliferative agents, and mammalian target of rapamycin inhibitors. However, individualized dosage regimens have not yet been fully established for these drugs except for therapeutic drug monitoring-based dosage modification because of extensive interindividual variations in immunosuppressive drug pharmacokinetics. The variations in immunosuppressive drug pharmacokinetics are attributed to interindividual variations in the functional activity of cytochrome P450 enzymes, UDP-glucuronosyltransferases, and ATP-binding cassette subfamily B member 1 (known as P-glycoprotein or multidrug resistance 1) in the liver and small intestine. Some genetic variations have been found to be involved to at least some degree in pharmacokinetic variations in post-transplant immunosuppressive therapy. It is well known that the frequencies and effect size of minor alleles vary greatly between different races. Thus, ethnic considerations might provide useful information for optimizing individualized immunosuppressive therapy after organ transplantation. Here, we review ethnic factors affecting the pharmacokinetics of immunosuppressive drugs requiring therapeutic drug monitoring, including tacrolimus, cyclosporine, mycophenolate mofetil, sirolimus, and everolimus.

Everolimus, an mTORC1/2 inhibitor, in ART-suppressed individuals who received solid organ transplantation: A prospective study

Pharmacologic inhibition of the mammalian target of rapamycin (mTOR) in the setting of renal transplantation has previously been associated with lower human immunodeficiency virus 1 (HIV-1) DNA burden, and in vitro studies suggest that mTOR inhibition may lead to HIV transcriptional silencing. Because prospective clinical trials are lacking, we conducted an open-label, single-arm study to determine the impact of the broad mTOR inhibitor, everolimus, on residual HIV burden, transcriptional gene expression profiles, and immune responses in HIV-infected adult solid organ transplant (SOT) recipients on antiretroviral therapy. Whereas everolimus therapy did not have an overall effect on cell-associated HIV-1 DNA and RNA levels in the entire cohort, participants who maintained everolimus time-averaged trough levels >5 ng/mL during the first 2 months of therapy had significantly lower RNA levels up to 6 months after the cessation of study drug. Time-averaged everolimus trough levels significantly correlated with greater inhibition of mTOR gene pathway transcriptional activity. Everolimus treatment also led to decreased PD-1 expression on certain T cell subsets. These data support the rationale for further study of the effects of mTOR inhibition on HIV transcriptional silencing in non-SOT populations, either alone or in combination with other strategies. Trial Registration: ClinicalTrials.gov NCT02429869.

A narrative review of the role of sirolimus in the treatment of congenital vascular malformations

OBJECTIVE

Vascular malformations arise from defects in the morphologic development of the vascular system and can have an impact on quality of life and/or lead to severe complications. To date, vascular malformations are frequently managed by invasive techniques, after which recurrence is common. Sirolimus, a downstream inhibitor of the phosphatidylinositol 3 kinase/AKT pathway and best known for its immunosuppressive effect, has been used off-label for lesions for which approved therapies were associated with unsatisfactory results or recurrence. The aim of this study was to review the available data on the effect of sirolimus on the size and symptoms of different types of malformations and to summarize the main safety issues.

METHODS

A literature search in Pubmed, Embase, Web of Science, and SCOPUS was performed. Case reports, case series, and clinical trials evaluating the effect of sirolimus in vascular malformations were eligible for this review. Fully terminated studies published between January 2010 and May 2019 reporting an evaluable response on size and/or symptoms were included. Relevant data on lesion size, symptoms, side effects and duration of treatment were extracted as reported in the study. Additionally, we reported 10 unpublished cases who were treated in UZ Leuven.

RESULTS

The literature review included 68 articles, describing 324 patients. The median duration of therapy was 12 months (range, 1-60 months). After 6 months of treatment, the size of the malformation had at least decreased in 67% of patients with common venous malformations (VM), in 93% of patients with blue rubber bleb nevus syndrome and in all patients with verrucous VM. The size of lymphatic malformations improved in more than 80% of the patients, even in the case of extensive involvement such as in Gorham-Stout disease and generalized lymphatic anomaly. In addition, the majority of patients with syndromic vascular malformations experienced a decrease in size and reported symptoms improved in almost all patients, regardless of the type of malformation. Side effects were common (53%) but usually mild; mucositis and bone marrow suppression were the most common. Regrowth or recurrence of symptoms occurred in 49% of patients who discontinued treatment. Comparable effects were seen in our own patients.

CONCLUSIONS

This review shows that sirolimus is effective in decreasing the size and/or symptoms of particularly lymphatic malformations as well as VMs. Although common, side effects were usually mild. Nevertheless, clinical trials are needed to confirm the safety and effectivity of sirolimus and to identify the required serum levels and duration of treatment.

The Effects of Continual Consumption of Origanum vulgare on Liver Transcriptomics

Simple Summary

The use of phytogenic products has entered mainstream use in the livestock industry as an antibiotic alternative. These products, often based on herbs and spices with established antimicrobial properties, are generally considered as safe and natural, however, they are often administered in high doses and frequency. The direct effects of these products on the livestock animals remains under-reported. Using a transcriptomics, we show that supplementing 2% oregano in feed has direct effects on gene expression in the livers of broilers with a potential range of beneficial and negative side effects.

Abstract

Pathogen control is re-emerging as a significant challenge to the health of both humans and animals. The livestock industry is in the process of massively replacing in-feed antibiotics with organic production friendly plant-based products. Nutrigenomics as a science of the effects of food constituents on gene expression is shedding more light on both benefits and detrimental side-effects of feed additive prolonged consumption on the host, indicating the need to understand the feed-host interactions and their influence on the host disease profile. In this study, we investigated the effects of 2% oregano powder supplementation on the liver gene expression in healthy male broilers from the hatch to 6 weeks of age. Deep RNAseq was performed on average 113.3 million paired and quality trimmed sequences per sample and four samples for the control and treatment each. The results demonstrate the severity of oregano effect on liver gene expression with substantial modifications in steroid hormone regulation, fat and carbohydrate metabolism alterations and strong influence on the host disease and function profile. Oregano supplementation was able to interfere with the transcriptional effects of a range of registered drugs and to significantly transcriptionally inhibit a range of cancer disease categories including liver cancer, and to modify fat and carbohydrate metabolism.

Characteristics of Lymphedema in Patients Treated with Mammalian Target of Rapamycin Inhibitors

Purpose: To investigate the characteristics of lymphedema in patients treated with mammalian target of rapamycin (mTOR) inhibitors and delineate complex decongestive therapy (CDT) outcomes. Methods and Results: We retrospectively analyzed 24 patients with mTOR inhibitor-induced lymphedema and 7 lymphedema patients (control) not treated with mTOR inhibitors, who visited the lymphedema clinic of the department of rehabilitation medicine from March 2016 to December 2019. We comprehensively reviewed clinical features, medication history, associated diseases, lymphoscintigraphy, lower extremity computed tomography venography (LE CTV), and the effect of CDT. By using ImageJ program, we measured the cross-sectional area (CSA) of muscle and subcutaneous fat of mid-thigh image in LE CTV and compared them to a control group not treated with mTOR inhibitors. Seventeen patients on sirolimus and seven patients on everolimus were included, with an approximately equal distribution of stages 2 and 3 lymphedema, and most with pitting edema. Ten patients had breast or gynecological cancer and underwent lymph node dissection. Lymphedema developed after mTOR inhibitor initiation, not postoperatively. Lymphoscintigraphy revealed decreased lymph node uptake and dermal backflow. LE CTV revealed subcutaneous honeycomb-shaped trabecular areas in the affected limbs of seven patients. Patients treated with mTOR inhibitors had a larger mean subcutaneous fat CSA and a smaller mean muscular CSA than controls. Lymphedema improved or remained unchanged after initial CDT. Daily CDT adequately controlled 11 cases, but exacerbation occurred in 5 of 7 poorly compliant patients, and cellulitis occurred in 6 patients. Conclusion: Physicians should identify mTOR inhibitor-related lymphedema early and discuss medication alternatives and CDT with patients.

Receptor tyrosine kinases-instructed release of its inhibitor from hydrogel to delay ovarian aging

Premature ovarian failure (POF) is the most frequently occurred disease in ovary. Direct inhibition of mammalian target of rapamycin (mTOR) activity can treat woman POF but brings adverse effects to women. Herein, by rational design of a hydrogelator Nap-Phe-Phe-Asp-Arg-Leu-Tyr-OH (Y) and co-assembling Y with an inhibitor of receptor tyrosine kinase (RTK, an upstream kinase of mTOR), Ala-Glu-Ala-Ala-Leu-Tyr-Lys-Asn-Leu-Leu-His-Ser-OH (Inh), to form hydrogel Gel Y + Inh, we develop a "smart" strategy of RTK-responsive disassembly of the hydrogel to release Inh. Release of Inh moderately inhibits the activity of mTOR and therefore delays ovarian aging. Oocyte and zygote experiments show that Gel Y + Inh improves both meiotic maturation of the oocytes and early embryonic development of the zygotes. In vivo animal experiments indicate that Gel Y + Inh effectively delays ovarian aging in aged mice by down regulation of mTOR activity, stimulation of ovaries to secrete estrogen and progesterone, and development of more antral follicles for reproduction. We expect that our new hydrogel Gel Y + Inh could be applied to treat woman POF, as well as delay ovarian aging, in clinic in the near future.

An update on current treatment strategies for managing bronchiolitis obliterans syndrome after lung transplantation

INTRODUCTION

Bronchiolitis obliterans syndrome (BOS), a subtype of chronic lung allograft dysfunction, is quite common, with up to half of all lung recipients developing BOS within 5 years of transplantation. Preventive efforts are aimed at alleviating known risk factors of BOS development, while the primary goal of treatment is to delay the irreversible, fibrotic airway changes, and progressive loss of lung function.

AREAS COVERED

This narrative review will briefly discuss the updated definition, clinical presentation, pathogenesis, risk factors, and survival after BOS while paying particular attention to the salient evidence for optimal preventive strategies and treatments based on investigations in the modern era.

EXPERT OPINION

Future translational research focused on further characterizing the complex interplay between immune and nonimmune mechanisms mediating chronic lung rejection is the first step toward mitigating risk of allograft injury, improving early disease detection with noninvasive biomarkers, and ultimately, developing an effective, targeted therapy that can extend the life of the lung allograft.

Diagnosis and management of oral ulcerations associated with mycophenolate mofetil in kidney transplantation

AIMS

The final diagnosis of oral mucosal ulcerations in solid organ transplant recipients represents a challenge. We describe a unique case of oral ulceration related to mycophenolate mofetil (MMF) toxicity, 11 years after kidney transplantation, whose dose reduction was sufficient to resolve it.

METHODS AND RESULTS

A 54-year-old female patient, who underwent kidney transplantation 11 years ago, presents multiple ulcers on the buccal mucosa bilaterally, soft palate and tongue dorsum, for 8 months, with moderate pain. The diagnosis of oral ulcerations associated with MMF therapy was assumed by excluding infection and malignancy diagnosis. After MMF dose reduction, the oral ulcers healed utterly.

CONCLUSIONS

MMF toxicity manifested as oral ulcers. Reduction or discontinuation of MMF therapy should be considered in a patient with refractory oral ulcers and a negative workup for other causes.

MRP4 is responsible for the efflux transport of mycophenolic acid β-d glucuronide (MPAG) from hepatocytes to blood

Mycophenolic acid (MPA) has become a cornerstone of immunosuppressive therapy, in particular for transplant patients. In the gastrointestinal tract, the liver and the kidney, MPA is mainly metabolized into phenyl-β-d glucuronide (MPAG). Knowledge about the interactions between MPA/MPAG and membrane transporters is still fragmented. The aim of the present study was to explore these interactions with the basolateral hepatic MRP4 transporter. The inhibition of the MRP4-driven transport by various drugs which can be concomitantly prescribed was also evaluated. In vitro experiments using vesicles overexpressing MRP4 showed an ATP-dependent transport of MPAG driven by MRP4 (Michaelis-Menten constant of 233.9 ± 32.8 µM). MPA was not effluxed by MRP4. MRP4-mediated transport of MPAG was inhibited (from -43% to -84%) by ibuprofen, cefazolin, cefotaxime and micafungin. An in silico approach based on molecular docking and molecular dynamics simulations rationalized the mode of binding of MPAG to MRP4. The presence of the glucuronide moiety in MPAG was highlighted as key, being prone to make electrostatic and H-bond interactions with specific residues of the MRP4 protein chamber. This explains why MPAG is a substrate of MRP4 whereas MPA is not.

Time-dependent lymphocyte count after transplantation is associated with higher risk of graft failure and death

The transplantation field requires the identification of specific risk factors associated with the level of immunosuppression. Here, our aim was to analyze the association between the number of circulating lymphocytes, monitored routinely by complete blood cell counts during outpatient visits, and patient and graft survival. In total, 2,999 kidney or combined kidney-pancreas recipients transplanted between 2000 and 2016, from two University hospitals, were enrolled. We investigated the etiological relationship between time-dependent lymphocyte count beyond one year after transplantation and patient and graft survival, viral infection and cancer risk using time-dependent multivariate Cox models. Model 1 considered kidney function at one year and model 2 as time-dependent variable. At the time of inclusion (one year after transplantation), 584 patients (19.4%) had deep lymphopenia (under 750 /mm³) and 1,072 (35.7%) had a normal count (over 1,500 /mm³). A patient with deep lymphopenia at a given follow-up time had significantly higher risks of graft failure, death and viral infection than comparable patients with a normal lymphocyte count at the same time point. Thus, after the first year of transplantation, the occurrence of deep lymphopenia within a patient's follow-up is a risk factor for long-term graft failure, death and viral infection.

COVID-19 in Kidney Transplantation: Outcomes, Immunosuppression Management, and Operational Challenges

The coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2, has led to the death of hundreds of thousands of people worldwide. If infected, older individuals and those with diabetes, hypertension, cardiovascular disease, and compromised immune systems are at higher risk for unfavorable outcomes. These comorbidities are prevalent in patients with kidney disease, hence the significant burden of COVID-19 on kidney transplant programs. Multiple case series of kidney transplant recipients with COVID-19 have shown increased mortality compared to nontransplant patients. To date, we do not have high-level evidence to inform immunosuppression minimization strategies in infected transplant recipients. Most centers however have adopted early antimetabolite withdrawal in addition to other interventions. This review summarizes the published COVID-19 literature as it relates to outcomes and immunosuppression management in kidney transplant recipients. It also discusses challenges pertaining to pretransplant evaluation and wait-listed patients.

MASS SPECTROMETRY-BASED PERSONALIZED DRUG THERAPY

Personalized drug therapy aims to provide tailored treatment for individual patient. Mass spectrometry (MS) is revolutionarily involved in this area because MS is a rapid, customizable, cost-effective, and easy to be used high-throughput method with high sensitivity, specificity, and accuracy. It is driving the formation of a new field, MS-based personalized drug therapy, which currently mainly includes five subfields: therapeutic drug monitoring (TDM), pharmacogenomics (PGx), pharmacomicrobiomics, pharmacoepigenomics, and immunopeptidomics. Gas chromatography-MS (GC-MS) and liquid chromatography-MS (LC-MS) are considered as the gold standard for TDM, which can be used to optimize drug dosage. Matrix-assisted laser desorption ionization-time of flight-MS (MALDI-TOF-MS) significantly improves the capability of detecting biomacromolecule, and largely promotes the application of MS in PGx. It is becoming an indispensable tool for genotyping, which is used to discover and validate genetic biomarkers. In addition, MALDI-TOF-MS also plays important roles in identity of human microbiome whose diversity can explain interindividual differences of drug response. Pharmacoepigenetics is to study the role of epigenetic factors in individualized drug treatment. MS can be used to discover and validate pharmacoepigenetic markers (DNA methylation, histone modification, and noncoding RNA). For the emerging cancer immunotherapy, personalized cancer vaccine has effective immunotherapeutic activity in the clinic. MS-based immunopeptidomics can effectively discover and screen neoantigens. This article systematically reviewed MS-based personalized drug therapy in the above mentioned five subfields. © 2020 John Wiley & Sons Ltd. Mass Spec Rev.

Rapamycin-based graft-versus-host disease prophylaxis increases the immunosuppressivity of myeloid-derived suppressor cells without affecting T cells and anti-tumor cytotoxicity

The immunosuppressant rapamycin (RAPA) inhibits mammalian target of rapamycin (mTOR) functions and is applied after allogeneic bone marrow transplantation (BMT) to attenuate the development of graft‐versus‐host disease (GVHD), although the cellular targets of RAPA treatment are not well defined. Allogeneic T cells are the main drivers of GVHD, while immunoregulatory myeloid‐derived suppressor cells (MDSCs) were recently identified as potent disease inhibitors. In this study, we analyzed whether RAPA prevents the deleterious effects of allogeneic T cells or supports the immunosuppressive functions of MDSCs in a BMT model with major histocompatibility complex (MHC) classes I and II disparities. RAPA treatment efficiently attenuated clinical and histological GVHD and strongly decreased disease‐induced mortality. Although splenocyte numbers increased during RAPA treatment, the ratio of effector T cells to MDSCs was unaltered. However, RAPA treatment induced massive changes in the genomic landscape of MDSCs preferentially up‐regulating genes responsible for uptake or signal transduction of lipopeptides and lipoproteins. Most importantly, MDSCs from RAPA‐treated mice exhibited increased immunosuppressive potential, which was primarily inducible nitric oxide synthase (iNOS)‐dependent. Surprisingly, RAPA treatment had no impact on the genomic landscape of T cells, which was reflected by unchanged expression of activation and exhaustion markers and cytokine profiles in T cells from RAPA‐treated and untreated mice. Similarly, T cell cytotoxicity and the graft‐versus‐tumor effect were maintained as co‐transplanted tumor cells were efficiently eradicated, indicating that the immunosuppressant RAPA might be an attractive approach to strengthen the immunosuppressive function of MDSCs without affecting T cell immunity.

Flucloxacillin decreases tacrolimus blood trough levels: a single-center retrospective cohort study

Purpose

Tacrolimus and everolimus are widely used to prevent allograft rejection. Both are metabolized by the hepatic cytochrome P450 (CYP) enzyme CYP3A4 and are substrate for P-glycoprotein (P-gp). Drugs influencing the activity or expression of CYP enzymes and P-gp can cause clinically relevant changes in the metabolism of immunosuppressants. Several case reports have reported that flucloxacillin appeared to decrease levels of drugs metabolized by CYP3A4 and P-gp. The magnitude of this decrease has not been reported yet.

Methods

In this single-center retrospective cohort study, we compared the tacrolimus and everolimus blood trough levels (corrected for the dose) before, during, and after flucloxacillin treatment in eleven transplant patients (tacrolimus n = 11 patients, everolimus n = 1 patient, flucloxacillin n = 11 patients).

Results

The median tacrolimus blood trough level decreased by 37.5% (interquartile range, IQR 26.4–49.7%) during flucloxacillin treatment. After discontinuation of flucloxacillin, the tacrolimus blood trough levels increased by a median of 33.7% (IQR 22.5–51.4%). A Wilcoxon signed-rank test showed statistically significantly lower tacrolimus trough levels during treatment with flucloxacillin compared with before (p = 0.009) and after flucloxacillin treatment (p = 0.010). In the only available case with concomitant everolimus and flucloxacillin treatment, the same pattern was observed.

Conclusions

Flucloxacillin decreases tacrolimus trough levels, possibly through a CYP3A4 and/or P-gp-inducing effect. It is strongly recommended to closely monitor tacrolimus and everolimus trough levels during flucloxacillin treatment and up to 2 weeks after discontinuation of flucloxacillin.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02968-z) contains supplementary material, which is available to authorized users.

Sirolimus-Eluting Electrospun-Produced Matrices as Coatings for Vascular Stents: Dependence of Drug Release on Matrix Structure and Composition of the External Environment

Although a number of drug-eluting coatings for vascular stents (VSs) have been developed and are in commercial use, more efficient stent coatings and drug delivery systems are needed. Sirolimus (SRL) is a clinically important drug with antiproliferative and immunosuppressive activities that is widely used for coating stents. Here, we characterized SRL-enriched matrices, intended for coating vascular stents, that were produced by electrospinning (ES) on a drum collector from a solution of polycaprolactone (PCL) and human serum albumin (HSA), 1,1,1,3,3,3-hexafluoroisopropanol (HFIP), dimethyl sulfoxide (DMSO), and SRL. The release of tritium-labeled SRL (³H-SRL) from matrices in phosphate-buffered saline (PBS) or human blood plasma (BP) was studied. The introduction of DMSO in the ES blend decreased SRL release. The use of BP significantly accelerated SRL release through binding with serum biomolecules. The exchange of PBS or BP after every time point also increased SRL release. The maximum SRL release in BP was observed at 3 days. The matrices produced from the ES solution with DMSO and HSA released no more than 80% SRL after 27 days in BP, even under medium exchange conditions. Therefore, PCL-based matrices containing HSA, SRL, and DMSO can be used for coating VSs with prolonged SRL delivery.

The advantage of Sirolimus in amplifying regulatory B cells and regulatory T cells in liver transplant patients

Sirolimus has been shown to ameliorate steroid-resistant rejection and induce long-term immune tolerance among liver transplant patients. However, the detailed mechanism of how Sirolimus achieve these advantages is still lacking. This study attempts to reveal some possible mechanisms by investigating regulatory B cells (Bregs), regulatory T cells (Tregs) and some cytokines in liver transplant recipients whose Tacrolimus was partially converted to Sirolimus. The results showed that CD19⁺CD24⁺CD38⁺Bregs and CD4⁺CD25⁺FoxP3⁺Tregs increased significantly during the first month after drug conversion (P < 0.01 and P < 0.05). The percentages of IL-10⁺Bregs and TGF-β₁⁺Bregs were also elevated (P < 0.05 and P < 0.01), and the same trend was observed in the levels of IL-10 and TGF-β₁ (P < 0.01 and P < 0.01). However, in the observation period, these investigated lymphocyte subsets and cytokines didn't change significantly in patients without Sirolimus usage. The incidence of biliary stenosis in the conversion group were significantly lower than that in the control group (P < 0.05). At the same time, in vitro experiments showed that Sirolimus could significantly amplify Bregs and Tregs (P < 0.01 and P < 0.01) while Tacrolimus did not show the amplifications effects. Sirolimus' function of amplifying Bregs was weakened, and its function of amplifying Tregs even disappeared after IL-10 and TGF-β₁ were neutralized. In conclusion, Sirolimus could amplify Bregs and Tregs among liver transplant recipient, which might be benefit to mitigate the immune response, decrease chances of rejection and alleviate biliary complication. IL-10 and TGF-β₁ may play important roles during this process.