Impact of intra-patient variability of tacrolimus on allograft function and CD4 + /CD8 + ratio in kidney transplant recipients: a retrospective single-center study.

BACKGROUND: Tacrolimus is a critical component of immunosuppressive therapy for kidney transplant recipients. Intra-patient variation (IPV) of tacrolimus levels affects the function of transplanted kidney. AIM: This study aimed to investigate the impact of tacrolimus IPV on kidney function, examine its association with post-transplant duration, and assess its effect on the immune status of transplant recipients. METHOD: This retrospective study was conducted from January 2016 to February 2022. IPV was evaluated using the coefficient of variation (CV) of tacrolimus trough levels from 6 to 48 months after transplantation. Patients were divided into low- and high-IPV groups based on the median CV. Significant differences in kidney function, CD4 + /CD8 + ratio, and post-transplant duration between these groups were analyzed. RESULTS: Among 189 patients, tacrolimus IPV showed a strong correlation with serum creatinine clearance rate (Ccr) and estimated glomerular filtration rate (eGFR) (p < 0.05). Tacrolimus IPV was significantly correlated with post-transplant duration in only two patients (p < 0.05). Using a median CV of 15.4% to categorize patients, the high IPV group, compared to the low IPV group, exhibited significantly higher eGFR at 6-9 months (p < 0.05), lower Ccr at 9-12 months (p < 0.05), and reduced Ccr and eGFR at 15-18 months (p < 0.05). Six months after transplantation, the high IPV group had a significantly lower CD4 + /CD8 + ratio than the low IPV group (p < 0.05). CONCLUSION: This study highlights the significant impact of tacrolimus IPV on transplant kidney function and immune status in transplant patients at various post-transplantation intervals.

Factors influencing methotrexate pharmacokinetics highlight the need for individualized dose adjustment: a systematic review.

PURPOSE: To develop a population pharmacokinetic (PPK) model for methotrexate (MTX) dosage for all ages, assess the association between concentration and clearance, and determine covariates affecting MTX disposition. METHODS: We compared MTX PK profiles among neonates, children, and adults by performing a systematic literature search for published population MTX models and conducted a Monte Carlo-based meta-analysis. Subsequently, we evaluated study quality and covariates significantly affecting dosage regimens and compared LDMTX and HDMTX PK profiles. RESULTS: Of the total 40 studies included, 34 were HDMTX, and six were LDMTX studies. For HDMTX, three studies involving neonates reported estimated apparent clearances (median, range) of 0.53 (0.27-0.77) L/kg/h; for 14 studies involving children, 0.23 (0.07-0.23) L/kg/h; and for 13 involving adults, 0.11 (0.03-0.22) L/kg/h. Neonates had a higher volume of distribution than children and adults. For LDMTX studies, apparent clearance was 0.085 (0.05-1.68) L/kg/h, and volume of distribution was 0.25 (0.018-0.47) L/kg, lower than those of HDMTX studies, with large between-subject variability. Bodyweight significantly influenced apparent clearance and volume of distribution, whereas renal function mainly influenced clearance. Mutations in certain genes reduced MTX clearance by 8-35.3%, whereas those in others increased it by 15-48%. Body surface area (BSA) significantly influenced apparent clearance with a median reduction of 51% when BSA increased in pediatric patients. CONCLUSIONS: Methotrexate dosage regimens were primarily based on body surface area and renal function. Further studies are needed to evaluate MTX pharmacokinetics and pharmacodynamics in both children (especially infants) and adults.

Validation and evaluation of a newly developed time-resolved fluoroimmunoassay for cyclosporine quantitative analysis in human whole blood.

Various immunoassay methods have been developed and used for the therapeutic drug monitoring (TDM) of cyclosporine (CsA). However, there is no report on the application of a time-resolved fluoroimmunoassay (TRFIA) in routine CsA TDM. The aim of this study was to evaluate the feasibility and validate the performance of a newly developed TRFIA method for CsA analysis in human whole blood. The TRFIA method was then compared with the method of chemiluminescent microparticle immunoassay (CMIA). The calibration range of the CsA-TRFIA method was 0-1000 ng/mL. The linear range and correlation coefficients were 30-1000 ng/mL and more than 0.990, respectively. The accuracy, precision, and inter-batch range were 90.0%-110.0%, less than 10%, and no more than 15%, respectively. The lowest limit of detection was less than 10 ng/mL. The linear regression equation was YCMIA = 0.961XTRFIA + 3.357, which showed that the measurements of CMIA and TRFIA were strongly correlated (r = 0.980). The results demonstrate that TRFIA is a precise and reproducible method for detecting the CsA concentration and can be used for routinely CsA TDM.

Dynamic Alterations in the Gut Microbiota of Collagen-Induced Arthritis Rats Following the Prolonged Administration of Total Glucosides of Paeony.

Rheumatoid arthritis (RA) is a common autoimmune disease linked to chronic inflammation. Dysbiosis of the gut microbiota has been proposed to contribute to the risk of RA, and a large number of researchers have investigated the gut-joint axis hypothesis using the collagen-induced arthritis (CIA) rats. However, previous studies mainly involved short-term experiments; very few used the CIA model to investigate changes in gut microbiota over time. Moreover, previous research failed to use the CIA model to carry out detailed investigations of the effects of drug treatments upon inflammation in the joints, hyperplasia of the synovium, imbalance in the ratios of Th1/Th2 and Th17/Treg cells, intestinal cytokines and the gut microbiota following long-term intervention. In the present study, we carried out a 16-week experiment to investigate changes in the gut microbiota of CIA rats, and evaluated the modulatory effect of total glucosides of paeony (TGP), an immunomodulatory agent widely used in the treatment of RA, after 12 weeks of administration. We found that taxonomic differences developed in the microbial structure between the CIA group and the Control group. Furthermore, the administration of TGP was able to correct 78% of these taxonomic differences, while also increase the relative abundance of certain forms of beneficial symbiotic bacteria. By the end of the experiment, TGP had reduced body weight, thymus index and inflammatory cell infiltration in the ankle joint of CIA rats. Furthermore, the administration of TGP had down-regulated the synovial content of VEGF and the levels of Th1 cells and Th17 cells in CIA rats, and up-regulated the levels of Th2 cells and Treg cells. The administration of TGP also inhibited the levels of intestinal cytokines, secretory immunoglobulin A (SIgA) and Interferon-γ (IFN-γ). In conclusion, the influence of TGP on dynamic changes in gut microbiota, along with the observed improvement of indicators related to CIA symptoms during 12 weeks of administration, supported the hypothesis that the microbiome may play a role in TGP-mediated therapeutic effects in CIA rats. The present study also indicated that the mechanism underlying these effects may be related to the regulation of intestinal mucosal immunity remains unknown and deserves further research attention.

A sample processing method for immunoassay of whole blood tacrolimus.

Current sample processing (SP) methods for tacrolimus (FK506) immunoassays are mainly based on extraction of drug by organic solvent and divalent metal ions. Although these methods are effective for drug extraction and interference elimination, they suffer from drawbacks including inconvenience for operation, difficulties for automation and potential measurement bias. To overcome these limitations, this study describes a new SP reagent for blood cell lysis and protein denaturation. A TRFIA (time-resolved fluorescence immunoassay) was developed by using this SP reagent for whole blood FK506 quantification. Results show that blood samples could be turned into homogeneous solution after being treated by this SP reagent, and so could be directly applied to immunoassays without centrifugation. The analytical sensitivity of the FK506-TRFIA was 0.57 ng/mL, the within-run and between-run coefficient of variations (CVs) were both less than 10%. The FK506 values of 126 samples obtained by FK506-TRFIA correlated excellently with that obtained by ABBOTT FK506-CMIA (R2 = 0.982). Comparison studies also show that the FK506-TRFIA was highly resistant to endogenous interferences. These results suggest that the present SP method is a more promising chose for FK506 immunoassay, and in the meantime, its simplicity makes the whole-process immunoassay automation more feasible by obviating the necessary for centrifugation.

Simultaneous Quantification of Five Sesquiterpene Components after Ultrasound Extraction in Artemisia annua L. by an Accurate and Rapid UPLC⁻PDA Assay.

Objective: To develop an accurate and rapid ultra-performance liquid chromatography (UPLC) coupled with a photodiode array (PDA) method for the simultaneous determination of artemisinin (Art), arteannuin B (Art B), arteannuin C (Art C), dihydroartemisinic acid (DHAA) and artemisinic acid (AA) in Artemisia annua L. Methodology: Chromatography separation was performed on an ACQUITY UPLC BEH C18 Column with isocratic elution; the mobile phase was 0.1% formic acid aqueous solution (A) and acetonitrile (B) (A:B = 40:60, v/v). Data were recorded at an ultraviolet (UV) wavelength of 191 nm for Art, Art C, DHAA and AA, and 206 nm for Art B. Results: The calibration curves of the five sesquiterpene components were all linear with correlation coefficients more than 0.9990. The linear ranges were 31.44-1572 µg/mL, 25.48-1274 µg/mL, 40.56-2028 µg/mL, 31.44-1572 µg/mL and 26.88-1396 µg/mL for Art, Art B, Art C, DHAA and AA, respectively. The precision ranged from 0.08% to 2.88%, the stability was from 0.96% to 1.66%, and the repeatability was all within 2.42% and had a mean extraction recovery of 96.5% to 100.6%. Conclusion: The established UPLC-PDA method would be valuable for improving the quantitative analysis of sesquiterpene components in Artemisia annua L.

Switching Immunosuppression From Cyclosporine to Tacrolimus in Kidney Transplant Recipients Based on CYP3A5 Genotyping.

BACKGROUND: Kidney transplant recipients on long-term cyclosporine (CsA) therapy may develop multiple adverse drug events, and immunosuppression conversion from CsA to tacrolimus (Tac) is an option. Genetic variations, especially cytochrome P450 (CYP) 3A5*3, affects Tac dosing. However, little information is available to guide the conversion with regards to patients' pharmacogenomics. We aimed to investigate whether CYP3A5, CYP3A4, and ABCB1 genotyping could contribute to a more precise and individualized initial dosing of Tac at the time of immunosuppressant conversion. METHODS: Genotypes of 5 candidate genes (CYP3A5*3, CYP3A4*1G, ABCB1C1236T, ABCB1C3435T, and ABCB1G2677T/A) were investigated by polymerase chain reaction and restriction fragment-length polymorphism methods in 46 adult kidney transplant recipients requiring immunosuppressant conversion from CsA to TAC. Associations between these functional genetic polymorphisms and the dose-adjusted trough concentrations of CsA and Tac were evaluated, retrospectively. RESULTS: Based on the linear regression analysis, CYP3A5 expressers (*1/*1 and *1/*3) had lower Tac dose-adjusted trough concentrations on days 7, 14, 21, and 28, and they required 1.40- to 1.75-fold higher daily dose to reach the target concentration compared with nonexpressers (*3/*3) on day 28 [0.07 (0.06-0.09) mg/kg/d versus 0.05 (0.02-0.06) mg/kg/d, P = 0.001]. CYP3A4*1G or ABCB1 genetic polymorphisms had no effect on the Tac dose-adjusted trough concentrations. CONCLUSIONS: Our preliminary study supports the use of CYP3A5 genotyping to guide the initial dosing of Tac when converting the immunosuppression therapy from CsA to Tac.