Despite excellent bactericidal effect, dosing adjustment of polymyxin B for patients with renal insufficiency and polymyxin B-related nephrotoxicity is still a major concern to clinicians. The aim of this study was to compare the population pharmacokinetic (PK) properties of polymyxin B in Chinese patients with different renal function and to investigate the relationship between PK parameters and polymyxin B related-acute kidney injury (AKI). A total of 37 patients with normal renal function (creatinine clearance ≥ 80 mL/min) and 33 with renal insufficiency (creatinine clearance < 80 mL/min) were included. In the two-compartment population PK models, the Cl (2.19 L/h vs 1.58 L/h; P < 0.001) and Q (13.83 L/h vs 10.28 L/h; P < 0.001) values were significantly different between the two groups. The simulated AUCss,24h values for patients with normal renal function were higher than those for patients with renal insufficiency. However, the renal dosing adjustment of polymyxin B seemed not to be necessary. Besides, during the treatment, AKI occurred in 23 (32.86%) patients. The polymyxin B AUCss,24h in patients with AKI was significantly higher than that in patients without AKI (108.66 ± 70.10 mg⋅h/L vs 66.18 ± 34.79 mg⋅h/L; P = 0.001). Both the ROC curve and Logistic regression analysis showed AUCss,24h > 100 mg⋅h/L was a good predictor for the probability of nephrotoxicity.

Polymyxin B is used as a last therapeutic option for the treatment of multidrug-resistant Gram-negative bacterial infections. This study aimed to develop a population pharmacokinetic model and limited sampling strategy, a method to estimate the area under the concentration curve (AUC) by using a limited number of samples, to assist therapeutic drug monitoring of polymyxin B in Chinese patients. Population pharmacokinetic analysis was performed using Phoenix ® NLME with data obtained from 46 adult patients at steady state. Various demographic variables were investigated as potential covariates for population pharmacokinetic modeling. The limited sampling strategies based on the Bayesian approach and multiple linear regression were validated using the intraclass correlation coefficient and Bland-Altman analysis. As a result, the data was described by a two-compartment population pharmacokinetic model. Through the modeling, creatinine clearance was found to be a statistically significant covariate influencing polymyxin B clearance. The limited sampling strategies showed the twopoint model (C 0h and C 2h) could predict polymyxin B exposure with good linear relativity (r 2 > 0.98), and the four-point model (C 1h , C1 .5h , C 4h , and C 8h) performed best in predicting polymyxin B AUC (r 2 > 0.99). In conclusion, this study successfully developed a population pharmacokinetic model and limited sampling strategies that could be applied in clinical practice to assist in therapeutic drug monitoring of polymyxin B in Chinese patients.

Parkinson is the second common neurodegenerative disease. The characteristics of Parkinson's disease (PD) are the dopamin neurons loss caused by neuroinflammation responses. C alycosin, an isoflavone phytoestrogen isolated from Astragalus membranaceus, has multiple pharmacological activities, such as anti-inflammation, anti-tumor, and neuroprotective effects. However, it is unknown whether calycosin can mitigate PD symptoms. This study aims to explore whether calycosin can alleviate PD symptoms and the underlying mechanisms. PD was induced in mice by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) injection, and calycosin was given intracerebroventricularly to these mice. A cell model of nerve inflammation was established by BV2 microglia cells injected with lipopolysaccharide (LPS). The motor states were evaluated by stepping, whisker, and cylinder experiments. The states of dopaminergic neurons and microglia were detected by immunostainning of tyrosine hydroxylase and cluster of differentiation molecule 11b (CD11b). The expression levels of inflammatory factors were detected by qPCR. Toll-like receptor (TLR)/ nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways were investigated by western blot. We found that calycosin treatment mitigated the behavioral dysfunctions and inflammatory responses in MPTP-induced PD mice. The TLR/NF-κB and MAPK pathways in MPTP-induced PD mice were inhibited by calycosin treatment, which was coincident with experiments in LPS-induced BV2 cells. Above all, calycosin mitigates PD symptoms through TLR/NF-κB and MAPK pathways in mice and cell lines.KEYWORDS

No abstract