Effect of Itraconazole and Its Metabolite Hydroxyitraconazole on the Blood Concentrations of Cyclosporine and Tacrolimus in Lung Transplant Recipients.

Invasive Aspergillus infection is a major factor for poor prognosis in patients receiving lung transplantation (LT). An antifungal agent, itraconazole (ITCZ), that has antimicrobial activity against Aspergillus species, is used as a prophylactic agent against Aspergillus infection after LT. ITCZ and its metabolite, hydroxyitraconazole (OH-ITCZ), potently inhibit CYP3A and P-glycoprotein that metabolize or excrete calcineurin inhibitors (CNIs), which are the first-line immunosuppressants used after LT; thus, concomitant use of ITCZ and CNIs could induce an increase in the blood concentration of CNIs. However, no criteria for dose reduction of CNIs upon concomitant use with ITCZ in LT recipients have been defined. In this study, the effect of ITCZ and OH-ITCZ on the blood concentrations of two CNIs, tacrolimus and cyclosporine, after LT were retrospectively evaluated. A total of 39 patients who received LT were evaluated. Effects of ITCZ and OH-ITCZ on the concentration/dosage (C/D) ratio of tacrolimus and cyclosporine were analyzed using linear mixed-effects models. The plasma concentrations of OH-ITCZ were about 2.5-fold higher than those of ITCZ. Moreover, there was a significant correlation between the plasma concentrations of ITCZ and OH-ITCZ. Based on parameters obtained in the linear regression analysis, the C/D ratios of cyclosporine and tacrolimus increase by an average of 2.25- and 2.70-fold, respectively, when the total plasma concentration of ITCZ plus OH-ITCZ is 1000 ng/mL. In conclusion, the plasma levels of ITCZ and OH-ITCZ could be key factors in drawing up the criterion for dose reduction of CNIs.

A Minimal Physiologically-Based Pharmacokinetic Model for Tacrolimus in Living-Donor Liver Transplantation: Perspectives Related to Liver Regeneration and the cytochrome P450 3A5 (CYP3A5) Genotype.

In adult patients after living-donor liver transplantation, postoperative days and the cytochrome P450 3A5 (CYP3A5) genotype are known to affect tacrolimus pharmacokinetics. In this study, we constructed a physiologically-based pharmacokinetic model adapted to the clinical data and evaluated the contribution of liver regeneration as well as hepatic and intestine CYP3A5 genotypes on tacrolimus pharmacokinetics. As a result, liver function recovered immediately and affected the total body clearance of tacrolimus only during a limited period after living-donor liver transplantation. The clearance was about 1.35-fold higher in the recipients who had a liver with the CYP3A5*1 allele than in those with the CYP3A5*3/*3 genotype, whereas bioavailability was ~0.7-fold higher in the recipients who had intestines with the CYP3A5*1 allele than those with CYP3A5*3/*3. In conclusion, the constructed physiologically-based pharmacokinetic model clarified that the oral clearance of tacrolimus was affected by the CYP3A5 genotypes in both the liver and intestine to the same extent.

Novel mouse model of chronic inflammatory and overactive bladder by a single intravesical injection of hydrogen peroxide.

There is so far no generally accepted animal model of chronic cystitis by which potential therapies can be evaluated. In this study, we aimed to establish a new mouse model of cystitis based on the proinflammatory effects of reactive oxygen species. A single intravesical injection of 1.5% hydrogen peroxide (H2O2) significantly increased the numbers of voids by 1 day after injection in female mice, which lasted up to 7 days. The H2O2 injection rapidly increased the bladder weight by 3 h in parallel with the histological damage and hyperpermeability of urothelial barrier. Although the urothelial dysfunction was recovered to normal by 7 days, increase in bladder weight, edematous thickening of the submucosa, and vascular hyperpermeability were apparent even 7 days after injection. During the time course, massive infiltration of neutrophils and increased expression of inflammatory cytokines were observed in the bladder. An intraperitoneal administration of oxybutynin, amitriptyline, indomethacin, or morphine attenuated the H2O2-induced frequent urination. These findings suggest that an intravesical injection of H2O2 induces relatively long-lasting inflammatory and overactive bladder, compared with existing cystitis models. The intravesical H2O2 injection model may be a simple and useful tool in the pathological study and drug discovery for chronic cystitis.