Clinical Pharmacokinetic Characteristics And The Mechanism Of Voriconazole Induced Liver Injury Under Inflammatory State

Drug-induced liver injury is the most common cause of acute liver failure(ALF).Except for acetaminophen overdose,most of the drug-induced liver injuries encountered in clinical practice are heterogeneous.Voriconazole,a broad-spectrum triazole antifungal agent,has attracted much attention in recent years due to frequent adverse reactions such as hepatotoxicity and drug withdrawal events.Firstly,a population pharmacokinetic(PPK)model of voriconazole was established in this study.According to the clinical data and serum trough concentration of patients taking voriconazole,PPK analysis was conducted to investigate the influence of various factors on the pharmacokinetic characteristics of voriconazole.The model was verified by goodness of fit plotting method,non-parametric bootstrap-up method,visual prediction test(VPC)and normalized prediction distribution error(NPDES).PPK analysis showed that VCZ and its metabolite VNO were characterized by one-compartment model with first-order absorption and nonlinear elimination,and CYP2C19 genotype was a significant factor affecting VCZ clearance.The pharmacokinetic parameters of VCZ and VNO in children were obtained by Bayesian feedback method,including the trough concentration,peak concentration,AUC of VCZ and VNO,and the ratio of the metabolite VNO.The final model demonstrated that the prediction of VCZ and VNO concentration is accurate.Through the construction of PPK model,we predicted the steady-state plasma concentrations of VCZ and VNO in patients.According to the clinical data,the correlation between the drug exposure of voriconazole and its main metabolite VNO and liver injury was investigated.The results showed that there were no significant correlation between liver injury and the steady peak concentration,steady trough concentration or the ratio of the metabolite VNO.These results indicated that although CYP2C19 affected the drug exposure of voriconazole,there was no correlation between the exposure of voriconazole and liver injury,suggesting that drug-induced liver injury caused by VCZ was related to other potential factors.As such,we analyzed the clinical data,and explored the relationship between inflammation and liver injury caused by VCZ based on logistic regression model.The results showed that there was a correlation between elevated CRP index and liver injury.In addition,a total number of 22 metabolites were identified and the metabolic pathways include oxidation,reduction,dehydration,cracking,methylation and glucose aldehyde acidification,etc.These findings enrich the current understanding of voriconazole metabolic pathways provide a newidea for adverse reactions of voriconazole such as liver injury.In order to further study the detailed mechanisms of liver injury caused by VCZ under inflammatory state,liver injury model using wild type and TLR4 gene knockout mice was constructed.12 wild type C57 mice along with 12 TLR4 gene knockout mice were divided into two groups: LPS and LPS + VCZ groups.LPS group was first given LPS solution,and injected again at 22 hours,then given normal saline at 24 hours.The LPS+VCZ group was the same as the LPS group,but only the normal saline was replaced with VCZ solution.The plasma samples of 6h,12 h,24h,gallbladder and liver of mice were collected.The liver biochemical indexes were determined,the pathological changes of liver tissue sections were observed,and the gene and protein levels of the upstream and downstream molecules of the possible pathway were detected by Western-blot and real-time fluorescence quantitative PCR.The results show that the proinflammatory cytokines,IL-6,IL-1β and TNF-α of LPS group of wild type mice significant higher than that of type knockout mice.LPS is a component of the cell wall of Gram-negative bacteria while TLR4 is a receptor for LPS.When the function of TLR4 in the knockout mice was deficient,LPS could not bind to TLR4 to activate the inflammatory pathway,indicating that the inflammatory modeling of the wild-type mice was successful.Compared with wild type mice of LPS + VCZ group,Plasma levels of liver function biochemical indexes ALT,AST,AKP,TBA were increased.Liver tissue pathological sections showed hepatocyte damage,while bile acid transporters BSEP and MRP2 were significantly down-regulated,and NTCP,CYP7A1 were significantly up-regulated,as well as nuclear receptor FXR expression was decreased,suggesting that voriconazole may induce hepatotoxicity in wild-type mice under inflammatory state.TLR4 mice did not showed obvious inflammation and liver damage.These results suggested that VCZ-induced liver injury may be related to TLR4-mediated inflammatory signaling pathway.In conclusion,CYP2C19 gene polymorphism was related to the exposure of VCZ and VNO.Correlation analysis showed that drug exposure had no correlation with liver injury caused by VCZ,while inflammation has a certain correlation with liver injury.In addition,the identification of voriconazole metabolites enriches the metabolic pathway of VCZ and provides new research ideas for its adverse reactions such as hepatotoxicity.Animal experiments showed that VCZ induced liver damage in mice under inflammatory state.The possible mechanism is that LPS binds to TLR4,activates the inflammatory signaling pathway,and increases the release of pro-inflammatory cytokines IL-6,IL-1β and TNF-α,which lowers the liver injury threshold of voriconazole.Proinflammatory cytokines induced drug-induced liver injury by inhibiting the activity of nuclear receptor FXR,followed by increasing synthesis of bile acids and inhibition of efflux of bile acids.