Optimal Trough Concentration of Tacrolimus in Pediatric Patients With Primary Nephrotic Syndrome

The trough concentration (C0) of tacrolimus in children with nephrotic syndrome (NS) has rarely been explored, so its target level was based on transplant research. This study aimed to determine the optimal tacrolimus C0 in NS children. Data from primary NS children treated with tacrolimus at Wuhan Children's Hospital in the last 10 years were retrospectively collected. According to the cutoff C0 analyzed by receiver-operator characteristics (ROC) analysis, patients were divided into very low- (< 4 ng/mL), low- (4-5 ng/mL), medium- (5-7 ng/mL), and high-concentration (7-10 ng/mL) groups. A total of 196 patients were enrolled for primary outcome analysis. Compared to medium-concentration group, only the very low-concentration group obtained significant inferior primary outcomes, including overall remission rate, relapse-free survival rate, and relapse rate at 6 months. For secondary outcomes, the very low-concentration group experienced more frequent treatment failure in 12 months, whereas the high-concentration group suffered a higher risk of adverse events than the medium-concentration group. For steroid-resistant NS, very low- and low-concentration groups required longer time to achieve remission compared to medium-concentration group. For steroid-sensitive NS, the very low-concentration group suffered a higher relapse frequency than medium-concentration group. Lastly, the dose of tacrolimus required for children with different CYP3A5 genotypes with or without Wuzhi capsules was analyzed. In conclusion, tacrolimus may be targeted to C0 of 4-7 ng/mL during the first 6 months in children with NS. For steroid-resistant NS, C0 of 5-7 ng/mL can achieve a rapid remission.

A joint population pharmacokinetic model to assess the high variability of whole-blood and intracellular tacrolimus in early adult renal transplant recipients

Tacrolimus (TAC) has high pharmacokinetic (PK) variability during the early transplantation period. The relationships between whole-blood and intracellular TAC concentrations and clinical outcomes remain controversial. This study identifies the factors affecting the PK variability of TAC and characterizes the relationships between whole-blood and intracellular TAC concentrations. Data regarding whole-blood TAC concentrations of 1,787 samples from 215 renal transplant recipients (<90 days postoperative) across two centers and intracellular TAC concentrations (648 samples) digitized from previous studies were analyzed using nonlinear mixed-effects modeling. The effects of potential covariates were screened, and the distribution of whole-blood to intracellular TAC concentration ratios (RWB:IC) was estimated. The final model was evaluated using bootstrap, goodness of fit, and prediction-corrected visual predictive checks. The optimal dosing regimens and target ranges for each type of immune cell subsets were determined using Monte Carlo simulations. A two-compartment model adequately described the data, and the estimated mean TAC CL/F was 23.6 L·h-1 (relative standard error: 11.5 %). The hematocrit level, CYP3A5*3 carrier status, co-administration with Wuzhi capsules, and tapering prednisolone dose may contribute to the high variability of TAC PK variability during the early post-transplant period. The estimated RWB:IC of all TAC concentrations in peripheral blood mononuclear cells (PBMCs) was 4940, and inter-center variability of PBMCs was observed. The simulated TAC target range in PBMCs was 20.2-85.9 pg·million cells-1. Inter-center variability in intracellular concentrations should be taken into account in further analyses. TAC dosage adjustments can be guided based on PK/PD variability and simulated intracellular concentrations.

Evidence of the interactions between immunosuppressive drugs used in autoimmune rheumatic diseases and Chinese herbal medicine: A scoping review

OBJECTIVES

Chinese herbal medicine (CHM) has been shown to be effective in autoimmune rheumatic diseases, but harmful herb-drug interactions might be inherent. We aim to review the evidence regarding herb-drug interactions between immunosuppressive drugs used in autoimmune rheumatic diseases and CHM.

METHODS

We searched PubMed, EMBASE and CINAHL from inception till 30 April 2023 using keywords that encompassed 'herb-drug interactions', 'herbs' and 'immunosuppressants'. Articles were included if they contained reports about interactions between immunosuppressive drugs used in the treatment of rheumatic diseases with CHM. Level of evidence for each pair of interaction was graded using the algorithm developed by Colalto.

RESULTS

A total of 65 articles and 44 unique pairs of interactions were identified. HDIs were reported for cyclophosphamide, cyclosporine, tacrolimus, methotrexate, mycophenolic acid, glucocorticoids, sulfasalazine, tofacitinib and biologic disease-modifying antirheumatic drugs. Among these, cyclosporine (n = 27, 41.5%) and tacrolimus (n = 19, 29.2%) had the highest number of documented interactions. Hypericum perforatum had the highest level of evidence of interaction with cyclosporine and tacrolimus. Consumption reduced the bioavailability and therapeutic effects of the drugs. Schisandra sphenanthera had the highest level of evidence of interaction with tacrolimus and increased the bioavailability of the drug. Majority of the articles were animal studies.

CONCLUSION

Overall level of evidence for the included studies were low, though interactions between cyclosporine, tacrolimus, Hypericum perforatum and Schisandra sphenanthera were the most and well-documented. Healthcare professionals should actively enquire about the concurrent use of CHM in patients, especially when drugs with a narrow therapeutic index are consumed.

Effects of WuZhi preparations on tacrolimus in pediatric and adult patients carrying the CYP3A5*1 allele of heart transplant during the early period after transplantation

AIM

Wuzhi preparations (WZP) are commonly administrated with tacrolimus (TAC) in China to improve the liver function and increase the exposure of TAC. This study aims to investigate the effects of WZP on TAC in pediatric heart transplantation (HTx) patients carrying the CYP3A5*1 allele during the early period after transplantation and also make a comparison with these effects in adult recipients.

METHODS

A total of 81 recipients with CYP3A5*1 allele were included and divided into the pediatric group (n = 29) and adult group (n = 52). The changes in TAC dose-corrected trough blood concentrations (C0 /D), dose requirement as well as intra-patient variability(IPV) of C0 /D after co-therapy with WZP were evaluated.

RESULTS

The TAC C0 /D was significantly increased 1.7 and 1.8 times after co-administration of WZP in the pediatric and adult groups, respectively. We further analyzed the pediatric patients, found that no statistical difference was observed in TAC C0 /D before and after co-therapy with WZP in children <6 years old. The changes of C0 /D increased with the dose of the active ingredient (Schisantherin A) in adult patients, but not in pediatric patients. TAC IPV was reduced by 10.5% in pediatric patients and 4.8% in adult patients when co-administrated with WZP. Furthermore, after taking WZP, the AST and TB were dramatically lowered in pediatric recipients.

CONCLUSION

Our study is the first attempt to demonstrate the effects of WZP on TAC in pediatric HTx recipients. By comparing these effects to those observed in adult recipients, valuable insights can be gained regarding the efficacy and potential benefits of WZP in the pediatric population.

Tissue-specific transcriptome and metabolome analyses reveal candidate genes for lignan biosynthesis in the medicinal plant Schisandra sphenanthera

Schisandra sphenanthera is an extremely important medicinal plant, and its main medicinal component is bioactive lignans. The S. sphenanthera fruit is preferred by the majority of consumers, and the root, stem, and leaf are not fully used. To better understand the lignan metabolic pathway, transcriptome and metabolome analyses were performed on the four major tissues of S. sphenanthera. A total of 167,972,229 transcripts and 91,215,760 unigenes with an average length of 752 bp were identified. Tissue-specific gene analysis revealed that the root had the highest abundance of unique unigenes (9703), and the leaves had the lowest (189). Transcription factor analysis showed that MYB-, bHLH- and ERF-transcription factors, which played important roles in the regulation of secondary metabolism, showed rich expression patterns and may be involved in the regulation of processes involved in lignan metabolism. In different tissues, lignans were preferentially enriched in fruit and roots by gene expression profiles related to lignan metabolism and relative lignan compound content. Furthermore, schisandrin B is an important compound in S. sphenanthera. According to weighted gene co-expression network analysis, PAL1, C4H-2, CAD1, CYB8, OMT27, OMT57, MYB18, bHLH3, and bHLH5 can be related to the accumulation of lignans in S. sphenanthera fruit, CCR5, SDH4, CYP8, CYP20, and ERF7 can be related to the accumulation of lignans in S. sphenanthera roots. In this study, transcriptome sequencing and targeted metabolic analysis of lignans will lay a foundation for the further study of their biosynthetic genes.

Effect of Wuzhi preparations on tacrolimus in CYP3A5 expressers during the early period after transplantation: A real-life experience from heart transplant recipients

BACKGROUND

Genetic polymorphisms and drug interactions are associated with tacrolimus exposure. This study aimed to evaluate the effect of Wuzhi (WZ) preparations on tacrolimus (TAC) concentration and dose requirements in heart transplant recipients with the CYP3A5*1 allele during the early period after transplantation.

METHODS

A total of 167 adult heart transplant recipients with the CYP3A5*1 allele were included and divided into the WZ group (n = 115) and the WZ-free group (n = 52). Blood trough concentrations of TAC were detected and the dose-adjusted concentration (C₀/D) and dose requirement for achieving the TAC therapeutic range were compared between the two groups. The change in C₀/D and dose of TAC were evaluated before and after co-administration with WZ preparations.

RESULTS

No significant differences in TAC C₀/D and dose requirement were observed between the WZ and WZ-free groups. However, the TAC C₀/D in the WZ group was significantly increased an average of 2.10-fold after co-administration of WZ. Moreover, the degree of elevation was related to the dose of the active ingredient (Schisantherin A). Furthermore, ALT, AST, and TB levels were significantly reduced after administration of WZ preparations.

CONCLUSION

Co-administration of the WZ/TAC preparation, in heart transplant recipients carrying the CYP3A5*1 allele, considerably increased TAC concentration (C₀/D) while decreased high levels of leading indicators in the liver function. More importantly, the effect of the WZ/TAC preparation on C₀/D was a dose-dependent event. However, our finding needs to be further confirmed in a larger sample size.

Interactions between natural products and cancer treatments: underlying mechanisms and clinical importance

Natural products, also referred to as dietary supplements, complementary and alternative medicines, and health or food supplements are widely used by people living with cancer. These products are predominantly self-selected and taken concurrently with cancer treatments with the intention of improving quality of life, immune function and reducing cancer symptoms and treatment side effects. Concerns have been raised that concurrent use may lead to interactions resulting in adverse effects and unintended treatment outcomes. This review provides an overview of the mechanisms by which these interactions can occur and the current evidence about specific clinically important natural product-drug interactions. Clinical studies investigating pharmacokinetic interactions provide evidence that negative treatment outcomes may occur when Hypericum perforatum, Grapefruit, Schisandra sphenanthera, Curcuma longa or Hydrastis canadensis are taken concurrently with common cancer treatments. Conversely, pharmacodynamic interactions between Hangeshashinto (TJ-14) and some cancer treatments have been shown to reduce the side effects of diarrhoea and oral mucositis. In summary, research in this area is limited and requires further investigation.

Potential profound fluctuation in tacrolimus concentration on consumption of pomegranate rind extract: A Pharmacokinetic Experiment

Background: Presently, varied case reports demonstrated an increase or decrease in blood concentration of diverse conventional drugs, often co-administered with edible fruits, spices, or vegetables. The overarching aim of this research is to elucidate the fluctuations in tacrolimus (TAC) blood concentration on the consumption of pomegranate rind extract (PRE). Methods: A pharmacokinetic (PK) study was conducted with two groups, vis-a-vis PRE + TAC (3 mg/kg) and TAC (3 mg/kg) alone groups. An experimental study was conducted in three different manners: Single-dose (S) PRE (200 mg/kg), 7-day repetitive (7-R) PRE (200 mg/kg) dosing, and multiple (M) PRE doses (100, 200, 400, and 800 mg/kg). All the blood samples (approximately 300 μl) were drawn at different time intervals, i.e., 30 min, 1, 2, 4, 8, and 12 h after oral administration of TAC (3 mg/kg). The estimation of TAC in rat plasma was done using the hyphenated technique LC-MS/MS where the mass spectrometer used was a triple-stage quadrupole in multiple-reaction monitoring (MRM) mode. Results: The findings depict that in comparison with the TAC (3 mg/kg) alone group with the 7-day repetitive (7-R) PRE (200 mg/kg) dosing, the Cmax was found to be 9.03 ± 1.21 ng/ml; AUC from time zero to infinity (AUC0-∞), 61.91 ± 17.37 ngh/ml, while the TAC (3 mg/kg) + PRE group exhibited an increase in PK parameters of TAC (Cmax 22.48 ± 3.07 ng/ml; AUC0-∞ 153.08 ± 13.24 ng h/ml). The authors further investigated in what manner the PRE affects the PK of TAC in animals. For this, docking studies with major phytoconstituents present in the PRE with CYP3A4 isoenzyme were carried out. Ellagitannins (dock score, -11.64) and punicalagin (dock score, -10.68) were again used for molecular simulation studies with TAC. To validate our findings, a CYP3A4 inhibitory in vitro assay was conducted. Conclusion: Based on the integrated in vivo and in silico studies, we concluded that pomegranate rind extract interacts strongly with CYP isoenzyme and is therefore responsible for the altered PK profile of TAC.

Controversial Interactions of Tacrolimus with Dietary Supplements, Herbs and Food

Tacrolimus is an immunosuppressive calcineurin inhibitor used to prevent rejection in allogeneic organ transplant recipients, such as kidney, liver, heart or lung. It is metabolized in the liver, involving the cytochrome P450 (CYP3A4) isoform CYP3A4, and is characterized by a narrow therapeutic window, dose-dependent toxicity and high inter-individual and intra-individual variability. In view of the abovementioned facts, the aim of the study is to present selected interactions between tacrolimus and the commonly used dietary supplements, herbs and food. The review was based on the available scientific literature found in the PubMed, Scopus and Cochrane databases. An increase in the serum concentration of tacrolimus can be caused by CYP3A4 inhibitors, such as grapefruit, pomelo, clementine, pomegranate, ginger and turmeric, revealing the side effects of this drug, particularly nephrotoxicity. In contrast, CYP3A4 inducers, such as St. John’s Wort, may result in a lack of therapeutic effect by reducing the drug concentration. Additionally, the use of Panax ginseng, green tea, Schisandra sphenanthera and melatonin in patients receiving tacrolimus is highly controversial. Therefore, since alternative medicine constitutes an attractive treatment option for patients, modern healthcare should emphasize the potential interactions between herbal medicines and synthetic drugs. In fact, each drug or herbal supplement should be reported by the patient to the physician (concordance) if it is taken in the course of immunosuppressive therapy, since it may affect the pharmacokinetic and pharmacodynamic parameters of other preparations.

A modified LC-MS/MS method for the detection of whole blood tacrolimus and its clinical value in Chinese kidney transplant patients

Background

For patients who treated with tacrolimus after kidney transplant, therapeutic drug monitoring is essential to improve their prognosis. However, previous detection methods have limitations, such as the overestimation and unacceptable bias in the immunoassays. Precision medicine has been challenged. The liquid chromatography-tandem mass spectrometry (LC-MS/MS) method is recognized as the gold standard due to its accuracy and specificity, but lack of throughput and complex process limits its clinical application. Therefore, an accurate, simple and high throughput method for tacrolimus monitoring is needed for clinical practice.

Methods

A modified LC-MS/MS method was introduced and validated. Whole blood samples were prepared by a one-step protein precipitation method. Chromatographic separation was achieved using a Phenomenex Kinetex 2.6 μm XB-C18 2.1 × 50 mm column with a total run time of 3.5 min to avoid matrix effect. An electrospray ionization source (ESI) was used in positive ion multiple reaction monitoring (MRM) mode for mass spectrometric detection. In order to protect the mass spectrometer, only part of the sample after LC separation was allowed to enter the mass spectrum, through a two HPLC systems coupled one mass spectrometry design. In this way, the instrument throughput is also improved and realizing the detection of 2 samples within 3.5 min and carried out a shorter analyzing time for each sample of 1.75 min. Additionally, we calculated tacrolimus-intrapatient variant (Tac-IPV) based on this modified method and assessed the prognostic value of Tac-IPV in Chinese kidney transplant patients.

Results

The LC-MS/MS was modified by streamlining the procedure and increasing the throughput. The method proved to be accurate and reproducible with all performance parameters suitably meeting the clinical requirements over a calibration ranged from 0.37 to 42.90 ng/mL. Parameters such as linearity, limit of quantification (LoQ) and dilution integrity were validated with a clinical reportable range from 0.37 to 343.20 ng/mL, which was particularly useful for high drug concentrations patients (rare but very serious). Both cross-contamination and matrix effects were negligible. Clinical data of 83 patients showed that Tac-IPV was associated with poor kidney transplant outcome in Chinese (Hazard Ratio (HR) = 3.96, 4.75; 95% Cl: 1.10–14.21, 1.23–18.36; P < 0.05).

Conclusions

This modified LC-MS/MS method possessed high throughput and simple sample preparation, allowing it to meet daily clinical needs. At the same time, Tac-IPV based on this modified LC-MS/MS had excellent prognostic value in kidney transplantation. These advantages have great significance for the individualized treatment of Chinese kidney transplant patients and broad application of Tac-IPV.

Population pharmacokinetics and dosage optimization of tacrolimus coadministration with Wuzhi capsule in adult liver transplant patients

1. This study aimed to establish a population pharmacokinetic model of tacrolimus coadministration with Wuzhi capsule and optimize the dosage regimen in adult liver transplant patients.2. Totally 1327 tacrolimus trough concentrations from 116 adult liver transplant patients were obtained for model development. A one-compartment model with first-order absorption and elimination was used to analyse the data, and the final model was internally verified using a goodness-of-fit diagnostic plot, bootstrap methods, and visual prediction test. A total of 29 patients with 250 tacrolimus trough concentrations was used for external validation via prediction-based diagnostics. Additionally, the simulation was used to optimize the recommended dose of tacrolimus and Wuzhi capsules.3. The estimated apparent clearance and volume of the distribution of tacrolimus were 15.4 L/h and 1210 L, respectively. The tacrolimus daily dose, Wuzhi capsule daily dose, postoperative time, alanine transaminase, haemoglobin, total bilirubin, direct bilirubin, estimated glomerular filtration rate, and urea, concomitant with voriconazole and fluconazole, were identified as significant covariates affecting the pharmacokinetic parameters. Internal and external validation showed that the final model was stable and reliable for predicting performance.4. The final model could provide guidance for dosage optimization of tacrolimus coadministered with Wuzhi capsules in adult liver transplantation patients.

A Comprehensive Review of the Main Lignan Components of Schisandra chinensis (North Wu Wei Zi) and Schisandra sphenanthera (South Wu Wei Zi) and the Lignan-Induced Drug-Drug Interactions Based on the Inhibition of Cytochrome P450 and P-Glycoprotein Activities

Wu Wei Zi is the dried fruit of Schisandra chinensis (Turcz.) Baill. or Schisandra sphenanthera Rehd. et Wils. (family Magnoliaceae). As a homology of medicine and food, it has been widely used in China for thousands of years, to tonify the kidney, and ameliorate neurological, cardiovascular, liver, and gastrointestinal disorders. As its increasing health benefits and pharmacological value, many literatures have reported that the combination of Wu Wei Zi in patients has led to fluctuations in the blood level of the combined drug. Therefore, it is extremely important to evaluate its safety concern such as drug-drug interactions (DDIs) when patients are under the poly-therapeutic conditions. This review summarized the effects of Wu Wei Zi extract and its major lignan components on cytochrome P450 and P-glycoprotein activities, the change of which could induce metabolic DDIs. Our review also elaborated on the differences of the major lignan components of the two Schisandra species, as well as the absorption, distribution, metabolism, and elimination of the major lignans. In conclusion, these results would enhance our understanding of the DDI mechanisms involving Wu Wei Zi, and may potentially untangle some differing and conflicting results in the future.

Research Progress on the Pharmacological Action of Schisantherin A

Schisantherin A (Sch A) is a dibenzocyclooctadiene lignan monomer isolated from the fruit of Schisandra chinensis (Turcz.) Baill. (S. chinensis). At present, many studies have shown that Sch A has a wide range of pharmacological effects, including its anti-Parkinson and anti-inflammatory effects and ability to protect the liver, protect against ischemia-reperfusion (I/R) injury, suppress osteoclast formation, and improve learning and memory. Its mechanism may be related to the antioxidant, anti-inflammatory, and antiapoptotic properties of Sch A through the MAPK, NF-κB, AKT/GSK3β, and PI3K/AKT pathways. This is the first review of the recent studies on the pharmacological mechanism of Sch A.

A comprehensive review of ethnopharmacology, phytochemistry, pharmacology, and pharmacokinetics of Schisandra chinensis (Turcz.) Baill. and Schisandra sphenanthera Rehd. et Wils

ETHNOPHARMACOLOGICAL RELEVANCE

Schisandra chinensis (called bei-wuweizi in Chinese, S. chinensis) and Schisandra sphenanthera (called nan-wuweizi in Chinese, S. sphenanthera) are two highly similar plants in the Magnoliaceae family. Their dried ripe fruits are commonly used as traditional Chinese medicine in the treatment of coughs, palpitation, spermatorrhea, and insomnia. They also are traditionally used as tonics in Russia, Japan, and Korea.

AIM OF THE REVIEW

S. chinensis and S. sphenanthera are similar in appearance, traditional applications, ingredient compositions, and therapeutic effects. This review, therefore, aims to provide a systematic insight into the botanical background, ethnopharmacology, phytochemistry, pharmacology, pharmacokinetics, quality control, and toxicology of S. chinensis and S. sphenanthera, and to explore and present the similarities and differences between S. chinensis and S. sphenanthera.

MATERIALS AND METHODS

A comprehensive literature search regarding S. chinensis and S. sphenanthera was collected by using electronic databases including PubMed, SciFinder, Science Direct, Web of Science, CNKI, and the online ethnobotanical database.

RESULTS

In the 2020 Edition of Chinese Pharmacopoeia (ChP), there were 100 prescriptions containing S. chinensis, while only 11 contained S. sphenanthera. Totally, 306 and 238 compounds have been isolated and identified from S. chinensis and S. sphenanthera, respectively. Among these compounds, lignans, triterpenoids, essential oils, phenolic acid, flavonoids, phytosterols are the major composition. Through investigation of pharmacological activities, S. chinensis and S. sphenanthera have similar therapeutic effects including hepatoprotection, neuroprotection, cardioprotection, anticancer, antioxidation, anti-inflammation, and hypoglycemic effect. Besides, S. chinensis turns out to have more effects including reproductive regulation and immunomodulatory, antimicrobial, antitussive and antiasthmatic, anti-fatigue, antiarthritic, and bone remodeling effects. Both S. chinensis and S. sphenanthera have inhibitory effects on CYP3A and P-gp, which can mediate metabolism or efflux of substrates, and therefore interact with many drugs.

CONCLUSIONS

S. chinensis and S. sphenanthera have great similarities. Dibenzocyclooctadiene lignans are regarded to contribute to most of the bioactivities. Schisandrin A-C, schisandrol A-B, and schisantherin A, existing in both S. chinensis and S. sphenanthera but differing in the amount, are the main active components, which may contribute to the similarities and differences. Study corresponding to the traditional use is needed to reveal the deep connotation of the use of S. chinensis and S. sphenanthera as traditional Chinese medicine. In addition, a joint study of S. chinensis and S. sphenanthera can better show the difference between them, which can provide a reference for clinical application. It is worth mentioning that the inhibition of S. chinensis and S. sphenanthera on CYP3A and P-gp may lead to undesirable drug-drug interactions.

Schisandra sphenanthera: A Comprehensive Review of its Botany, Phytochemistry, Pharmacology, and Clinical Applications

Schisandra sphenanthera Rehd. et Wils (S. sphenanthera) is a single species of Schisandra genus, Magnoliaceae family, and it is a famous medicinal herb mostly growing in southern China, China Taiwan and Vietnam. S. sphenanthera is usually used for the treatments of hepatitis, Alzheimer's disease, renal transplantation, osteoporosis, and insomnia. In present studies, approximately 310 natural constituents have been isolated from S. sphenanthera, including lignans, triterpenes, volatile oils, and polysaccharides, which were mainly obtained from the fruits and stems of S. sphenanthera. Pharmocological studies have shown that the extracts and monomeric compounds of S. sphenanthera possessed wide-range bioactivities, such as antitumor, anti-oxidant, anti-inflammatory, osteoblastic, immune regulation, neuroprotective, kidney protection, hepatoprotective, and antiviral activities. However, resource availability, quality control measures, in-depth in vivo pharmacological study, and clinical application are still insufficient and deserve further studies. This review systematically summarized literatures on the botany, phytochemistry, pharmacology, development utilization, and clinical application of S. sphenanthera, in hopes of provide a useful reference for researchers for further studies of this plant.

Natural products: potential treatments for cisplatin-induced nephrotoxicity

Cisplatin is a clinically advanced and highly effective anticancer drug used in the treatment of a wide variety of malignancies, such as head and neck, lung, testis, ovary, breast cancer, etc. However, it has only a limited use in clinical practice due to its severe adverse effects, particularly nephrotoxicity; 20%–35% of patients develop acute kidney injury (AKI) after cisplatin administration. The nephrotoxic effect of cisplatin is cumulative and dose dependent and often necessitates dose reduction or withdrawal. Recurrent episodes of AKI result in impaired renal tubular function and acute renal failure, chronic kidney disease, uremia, and hypertensive nephropathy. The pathophysiology of cisplatin-induced AKI involves proximal tubular injury, apoptosis, oxidative stress, inflammation, and vascular injury in the kidneys. At present, there are no effective drugs or methods for cisplatin-induced kidney injury. Recent in vitro and in vivo studies show that numerous natural products (flavonoids, saponins, alkaloids, polysaccharide, phenylpropanoids, etc.) have specific antioxidant, anti-inflammatory, and anti-apoptotic properties that regulate the pathways associated with cisplatin-induced kidney damage. In this review we describe the molecular mechanisms of cisplatin-induced nephrotoxicity and summarize recent findings in the field of natural products that undermine these mechanisms to protect against cisplatin-induced kidney damage and provide potential strategies for AKI treatment.

Beneficial effects of Wuzhi Capsule on tacrolimus blood concentrations in liver transplant patients with different donor-recipient CYP3A5 genotypes

WHAT IS KNOWN AND OBJECTIVE

Tacrolimus (Tac) is an immunosuppressant that is widely used to prevent allograft rejection in patients after liver transplantation. Its metabolism mainly depends on the cytochrome P450 3A5 (CYP3A5), which has genetic polymorphisms. Recently, a Chinese herbal medicine known as Wuzhi Capsule (WZC) was shown to increase Tac blood concentrations by inhibiting the activity of CYP3A in animal studies in rats. To date, it remains unexplored whether WZC can be efficiently used to enhance the blood concentration of Tac in liver transplant patients with different donor-recipient CYP3A5 genotypes.

METHODS

A total of 185 liver transplant patients were enrolled and two-way ANOVA was carried out, then they were divided into four groups according to the combinations of donor-recipient CYP3A5 phenotypes. WZC was given to patients when the dose of Tac was ≥4 mg, and the dose-adjusted C₀ (C₀ /D) of Tac measured twice in succession was ≤1 ng/ml/mg. The blood trough concentration of Tac (C₀ ), C₀ /D, and dose- and body weight-adjusted C₀ (C₀ /D/W) was analysed on days 7 and 14 after liver transplantation.

RESULTS

The genotypes of donor and recipient or WZC had significant effects on C0, C0/D and C0/D/W. There were significant differences in the Tac blood concentrations between the groups. The recipient expression (*1)/donor expression (*1) (R+/D+) group had the lowest C₀ , C₀ /D and C₀ /D/W among the four groups. Furthermore, a larger proportion of patients in the CYP3A5 expression groups required Tac dose adjustment to achieve a therapeutic effect and were given Tac with WZC. Notably, the use of WZC significantly increased the blood concentrations of Tac in the CYP3A5 expression groups and greater increases in the C₀ /D and C₀ /D/W were significantly associated with higher doses of WZC in the CYP3A5 expression groups. What is more, WZC reduced the hospitalization cost of patients to a certain extent.

WHAT IS NEW AND CONCLUSION

WZC significantly increased the C₀ , C₀ /D and C₀ /D/W in the CYP3A5 expression groups and reduced the hospitalization expenses of patients to a certain extent. What is more, greater increases in the C₀ /D and C₀ /D/W were significantly associated with higher doses of WZC.

Functional CYP3A variants affecting tacrolimus trough blood concentrations in Chinese renal transplant recipients

The aim of this study was to identify novel genetic variants affecting tacrolimus trough blood concentrations. We analyzed the association between 58 single nucleotide polymorphisms (SNPs) across the CYP3A gene cluster and the log-transformed tacrolimus concentration/dose ratio (log (C₀/D)) in 819 renal transplant recipients (Discovery cohort). Multivariate linear regression was used to test for associations between tacrolimus log (C₀/D) and clinical factors. Luciferase reporter gene assays were used to evaluate the functions of select SNPs. Associations of putative functional SNPs with log (C₀/D) were further tested in 631 renal transplant recipients (Replication cohort). Nine SNPs were significantly associated with tacrolimus log (C₀/D) after adjustment for CYP3A5*3 and clinical factors. Dual luciferase reporter assays indicated that the rs4646450 G allele and rs3823812 T allele were significantly associated with increased normalized luciferase activity ratios (p < 0.01). Moreover, CYP3A7*2 was associated with higher TAC log(C₀/D) in the group of CYP3A5 expressers. Age, serum creatinine and hematocrit were significantly associated with tacrolimus log (C₀/D). CYP3A7*2, rs4646450, and rs3823812 are proposed as functional SNPs affecting tacrolimus trough blood concentrations in Chinese renal transplant recipients. Clinical factors also significantly affect tacrolimus metabolism.

Preoperative Management of Surgical Patients Using Dietary Supplements: Society for Perioperative Assessment and Quality Improvement (SPAQI) Consensus Statement

The widespread use of complementary products poses a challenge to clinicians in the perioperative period and may increase perioperative risk. Because dietary supplements are regulated differently from traditional pharmaceuticals and guidance is often lacking, the Society for Perioperative Assessment and Quality Improvement convened a group of experts to review available literature and create a set of consensus recommendations for the perioperative management of these supplements. Using a modified Delphi method, the authors developed recommendations for perioperative management of 83 dietary supplements. We have made our recommendations to discontinue or continue a dietary supplement based on the principle that without a demonstrated benefit, or with a demonstrated lack of harm, there is little downside in temporarily discontinuing an herbal supplement before surgery. Discussion with patients in the preoperative visit is a crucial time to educate patients as well as gather vital information. Patients should be specifically asked about use of dietary supplements and cannabinoids, as many will not volunteer this information. The preoperative clinic visit provides the best opportunity to educate patients about the perioperative management of various supplements as this visit is typically scheduled at least 2 weeks before the planned procedure.

Population pharmacokinetic analysis and dosing guidelines for tacrolimus co-administration with Wuzhi capsule in Chinese renal transplant recipients

WHAT IS KNOWN AND OBJECTIVES

Tacrolimus (TAC) is a first-line immunosuppressant which is used to prevent transplant rejection after solid organ transplantation (SOT). However, it has a narrow therapeutic index and high individual variability in pharmacokinetics (PK) and pharmacogenomics (PG). It has been reported that the metabolism of TAC can be affected by genetic factors, leading to different rates of metabolism in different subjects. Wuzhi Capsule (WZC) is a commonly used TAC-sparing agent in Chinese SOT to reduce TAC dosing due to its inhibitory effect on TAC metabolism by enzymes of the CYP3A subfamily. The aims of this study were to assess the effect of TAC+WZC co-administration and genetic polymorphism on the pharmacokinetics of TAC, by using a population pharmacokinetic (PPK) model. A dosing guideline for individualized TAC dosing is proposed based on the PPK study.

METHODS

The medical records of 165 adult patients with kidney transplant and their 824 TAC concentrations from two kidney transplantation centres were reviewed. The genotypes of four single-nucleotide polymorphisms (SNPs) in CYP3A5*3 and ABCB1 (rs1128503, rs2032582 and rs1045642) were tested by MASSARRAY. A PPK model was constructed by nonlinear mixed effect model (NONMEM^® , Version 7.3). Finally, Monte Carlo simulations were employed to design initial dosing regimens based on the final model.

RESULTS AND DISCUSSION

The one-compartmental PPK model with first-order absorption and elimination of TAC was established in kidney transplant recipients (KTRs). CYP3A5*3 had significant impact on the PPK model. The haematocrit (HCT), postoperative time (POD) and CYP3A5*3 genotypes had a significant influence on TAC clearance when combined with WZC. The model was expressed as 23.4 × (HCT/0.3)^-0.729  × 0.837 (combination with WZC) × e^{-0.0875(POD/12.6)} ×1.18 (CYP3A5 expressors). For patients carrying the CYP3A5*3/*3 allele and with 30% HCT, the required TAC dose to achieve target trough concentrations of 10-15 ng/ml was 4 mg twice daily (q12h). For patients with the CYP3A5*3/*3 allele, the required dose was 3 mg TAC q12h when combined with WZC, and for patients with the CYP3A5*1/*1 or *1/*3 allele, the required dose was 4 mg of TAC q12h when co-administered with WZC.

WHAT IS NEW AND CONCLUSION

Wuzhi Capsule co-administration and CYP3A5 variants affect the PK of TAC Dosing guidelines are made based on the PPK model to allow individualized administration of TAC, especially when co-administered with WZC.

Important considerations for drugs, nutritional, and herbal supplements in pediatric solid organ transplant recipients

Pediatric transplant recipients are on multiple prescription and non-prescription drugs. Many patients also use dietary, nutritional, and herbal supplements. This manuscript researched formulations of immunosuppressive drugs currently available and presents information on generic immunosuppressive drugs, commonly used non-prescription medications, dietary supplements, and herbal supplements. Immunosuppressive drugs are available in various formulations. Not all formulations are interchangeable. A number of FDA-approved generic formulations are available commercially in the United States. Generally generic formulations produce similar blood concentration vs time profiles compared to brand name products in adults and are considered to be bioequivalent. NSAID should be avoided in transplant patients due to potential drug interactions and increased risk associated with NSAID use; and appropriate doses of acetaminophen should be used for treatment of pain. Over-the-counter medications, such as guaifenesin and dextromethorphan, antihistamine medications, including diphenhydramine, loratadine, cetirizine, and fexofenadine, can be safely used in pediatric solid organ transplant population. Many safe and effective over-the-counter options exist for stool softening and as laxative. Diarrhea can lead to an increase in calcineurin inhibitor levels. Food can alter the absorption of immunosuppressive drugs. Several herbal products can alter immune status of the patients or alter the blood concentration of immunosuppressive drugs or may produce renal or hepatic toxicities and should be avoided in pediatric transplant recipients. It is important to educate pediatric transplant recipients and their families about not only immunosuppressive drug therapy but also about non-prescription drugs, dietary, and herbal supplement use.

Co-administration of Wuzhi tablet (Schisandra sphenanthera extract) alters tacrolimus pharmacokinetics in a dose- and time-dependent manner in rats

ETHNOPHARMACOLOGY RELEVANCE

Tacrolimus is a well-known potent but expensive immunosuppressant. We previously clarified the herb-drug interaction between tacrolimus and Wuzhi tablet (WZ), a prescribed drug of ethanol extract of Schisandra sphenanthera, and showed the ideal effect of WZ on maintaining therapeutic level of tacrolimus and reducing the total drug expense. However, WZ possesses a biphasic effect on regulating CYP3A (the major metabolizing enzyme of tacrolimus), which could induce the mRNA and protein expression after long-term treatment while transiently inhibit the activity of CYP3A. In clinic, clinicians are confused about the relationship between the blood concentration of tacrolimus and the dose and the duration of pretreatment of WZ. Therefore, the effects of the pretreatment time and the dose of WZ on the pharmacokinetics of tacrolimus is urgently needed to be clarified to better combine the use of WZ and tacrolimus in clinic.

AIM OF THE STUDY AND METHOD

This study aimed to investigate the effects of the pretreatment time and the dose of WZ on the pharmacokinetics of tacrolimus in rats.

RESULTS AND CONCLUSIONS

After pretreated rats with WZ for 0, 0.5, 2, 6, 12 or 24 h, the area under the curve (AUC) of tacrolimus was 2.27 ± 0.59, 1.87 ± 1.14, 2.86 ± 0.64, 1.62 ± 0.70, 1.54 ± 1.06 and 1.12 ± 0.69-fold of that of the tacrolimus alone group, respectively. The ratio of AUC of tacrolimus to that of the co-administration group with 0, 62.5, 125, 250, 500 or 750 mg/kg of WZ was 1.00: 1.07: 1.44: 2.60: 2.32: 2.42, respectively. These findings suggested that WZ increased tacrolimus AUC in a pretreatment time- and dose-dependent manner. In line with the in vivo findings, WZ extract inhibited CYP3A activity in a pre-treatment time- and concentration-dependent manner in human liver microsomes. In conclusion, the pharmacokinetics of tacrolimus was significantly affected by the pretreatment time and the dose of WZ. Oral pretreatment with WZ for 0-2 h or co-dosing of 250 mg/kg of WZ most significantly increased the blood concentration of tacrolimus. These findings would be helpful for guiding the reasonable use of WZ and tacrolimus in clinic.

Potential for pharmacokinetic interactions between Schisandra sphenanthera and bosutinib, but not imatinib: in vitro metabolism study combined with a physiologically-based pharmacokinetic modelling approach

AIMS

This study aimed to investigate the potential interaction between Schisandra sphenanthera, imatinib and bosutinib combining in vitro and in silico methods.

METHODS

In vitro metabolism of imatinib and bosutinib using recombinant enzymes and human liver microsomes were investigated in the presence and absence of Schisandra lignans. Physiologically-based pharmacokinetic (PBPK) models for the lignans accounting for reversible and mechanism-based inhibitions and induction of CYP3A enzymes were built in the Simcyp Simulator (version 17) and evaluated for their capability to predict interactions with midazolam and tacrolimus. Their potential effect on systemic exposures of imatinib and bosutinib were predicted using PBPK in silico simulations.

RESULTS

Schisantherin A and schisandrol B, but not schisandrin A, potently inhibited CYP3A4-mediated metabolism of imatinib and bosutinib. All three compounds showed a strong reversible inhibition on CYP2C8 enzyme with k_i of less than 0.5 μmol L^-1 . The verified PBPK models were able to describe the increase in systemic exposure of midazolam and tacrolimus due to co-administration of S. sphenanthera, consistent with the reported changes in the corresponding clinical interaction study (AUC ratio of 2.0 vs 2.1 and 2.4 vs 2.1, respectively). The PBPK simulation predicted that at recommended dosing regimens of S. sphenanthera, co-administration would result in an increase in bosutinib exposure (AUC ratio 3.0) but not in imatinib exposure.

CONCLUSION

PBPK models for Schisandra lignans were successfully developed. Interaction between imatinib and Schisandra lignans was unlikely to be of clinical importance. Conversely, S. sphenanthera at a clinically-relevant dose results in a predicted three-fold increase in bosutinib systemic exposure.

Risk factors and clinical characteristics of tacrolimus-induced acute nephrotoxicity in children with nephrotic syndrome: a retrospective case-control study

PURPOSE

Acute nephrotoxicity is a common adverse reaction of tacrolimus therapy; however, its risk factors in pediatric nephrotic syndrome (NS) remain to be evaluated. The objective of this study was to investigate the risk factors and characteristics of tacrolimus-induced acute nephrotoxicity in children with NS.

METHODS

Past records of children with NS admitted to our hospital from 2014 to 2018 were reviewed. The incidence and characteristics of nephrotoxicity were analyzed. Multivariate logistic regression analysis was used to identify the risk factors of nephrotoxicity. A clinically applicable risk score was developed and validated.

RESULTS

Tacrolimus-induced nephrotoxicity occurred in 25 of 129 patients, 13 patients were grade 1, and the renal function was recovered in 22 patients. Multivariate regression analysis showed that the maximum trough concentrations (C_12h) of tacrolimus (OR, 1.48; 95% CI, 1.16 to 1.88; P < 0.001), huaiqihuang granules (OR, 0.095; 95% CI, 0.014 to 0.66; P = 0.017), and diarrhea (OR, 22.00; 95% CI, 1.58 to 306.92; P = 0.022) were independently associated with tacrolimus-induced nephrotoxicity. The maximum C_12h were significantly higher in patients with nephrotoxicity (median 9.0 ng/ml) and the cut-off value for acute nephrotoxicity was 6.5 ng/ml. The area under the receiver operating characteristic curve was 0.821 for the proposed model based on the observations used to create the model and 0.817 obtained from k-fold cross-validation.

CONCLUSIONS

High trough concentration of tacrolimus and diarrhea can potentiate the risk of tacrolimus-induced acute nephrotoxicity in children with NS, while huaiqihuang granules can protect this condition.

Intrapatient Variability of Tacrolimus Exposure in Solid Organ Transplantation: A Novel Marker for Clinical Outcome

The calcineurin-inhibitor tacrolimus (Tac) provides an acceptable balance between prevention of allograft rejection and drug-related adverse effects, making it the standard of care in all types of solid organ transplantation for the last 2 decades. Recent data have demonstrated that high intrapatient variability (IPV) in Tac predose trough concentrations has deleterious effects on allograft survival. The underlying mechanisms by which a high Tac IPV shortens allograft survival are acute and chronic rejection, donor-specific anti-HLA antibodies, and progressive fibrotic damage to the graft. Modifiable causes of high Tac IPV include medication nonadherence (MNA), drug interactions, nutritional interferences, and concurrent diseases. Recognizing high Tac IPV as an important prognostic risk factor after solid organ transplantation requires understanding of the definitions, the use of correct diagnostic metrics, and methodology. Therapeutic interventions aimed at reducing Tac IPV are targeted on improving MNA, avoiding or adjusting drug interactions, drug dosing assists, and educational support of recipients.

Natural product drug delivery: A special challenge?

Natural products have a long-standing and critical role in drug development and medical use. The structural and physicochemical properties of natural products, while derived evolutionarily to be effective in living systems, may create challenges in translation to a pharmaceutical product. Molecular complexity, low solubility, functional group reactivity and general instability are among the challenges that typically need to be overcome. This review looks at some of the ways that natural products have been formulated and delivered to enable the successful application of these vitally important medicines to patients.

Prediction of tacrolimus dosage in the early period after heart transplantation: a population pharmacokinetic approach

Aim: The aim of this study was to evaluate tacrolimus population pharmacokinetics and investigate factors that explain tacrolimus variability in adult heart transplant patients. Methods: A total of 707 tacrolimus concentrations from 107 adult heart transplant patients were included in model development. The effects of demographic, clinical factors and CYP3A5 genotype on tacrolimus clearance were evaluated using a nonlinear mixed-effects modeling. 24 patients with 106 tacrolimus concentrations were used for external validation. Results: The pharmacokinetic data were adequately described by a one-compartment model with first-order absorption and elimination. The estimated apparent clearance and volume of distribution of tacrolimus were 13.7 l/h and 791 l, respectively. Tacrolimus apparent clearance was significantly reduced in CYP3A5 nonexpressers (CYP3A5*3/*3), concomitant with azole antifungal drugs and Wuzhi capsule (WZ). A predictive performance was further confirmed in an external validation by Bayesian estimation. Recommended dose regimens were obtained by simulations based on the established model. Conclusion: This is the first population pharmacokinetic study conducted in Chinese heart transplant recipients. These findings are of great importance with regards to tacrolimus dose optimization in heart transplantation patients.