Cytochrome P450 3A4 activity and genetic variants as predictors of liver failure in patients with obstructive jaundice.

Liver failure in patients with obstructive jaundice is a significant contributor to mortality within this patient cohort. The exact mechanism and triggers of this occurrence are yet to be fully understood. With this in mind, our study aimed to assess the correlation between the urinary 6 ß-OHC/C ratio and various biochemical parameters of liver function. Furthermore, we conducted genotyping of CYP3A4*22 (rs35599367), CYP3A5*3 (rs776746) polymorphic markers to investigate the potential effects of their variants on the probability of liver failure in obstructive jaundice. Our study included 75 patients diagnosed with severe obstructive jaundice. All test subjects underwent functional liver tests, and control blood tests were administered on the seventh day following biliary decompression. Patients were categorized into two groups: group 1 - patients without liver failure (n = 60) and group 2 - patients with liver failure (n = 15). Laboratory indexes such as 6 ß -OHC concentration and 6 ß- OHC/cortisol ratio can serve as significant predictors of liver failure in patients with moderate and severe degree obstructive jaundice after biliary decompression. Based on the study of "wild" and polymorphic variants of CYP3A4*22 (CC and CT) and polymorphism of CYP3A5*3A6986G (GG, GA, AA), it was discovered that liver failure in the CYP3A4*22 variant may be associated with the CC genotype, and in the CYP3A5*3 variant - with the GA genotype. Hence, the determination of 6ß- OHC concentration and 6ß- OHC/C ratio, as well as the analysis of polymorphic and "wild" variants of CYP3A4*22 (CC and CT) and CYP3A5*3 polymorphism A6986G (GG, GA, AA), may play a crucial role in predicting liver failure in patients with obstructive jaundice.

Comparative polymyxin B pharmacokinetics in patients receiving extracorporeal membrane oxygenation.

OBJECTIVES: To describe polymyxin B pharmacokinetics in patients receiving veno-venous extracorporeal membrane oxygenation (ECMO) in comparison with critically ill patients without ECMO support and to explore potential covariates that could affect the pharmacokinetics in this group of patients. PATIENTS AND METHODS: In 13 critically ill patients on ECMO and in 21 critically ill patients without ECMO support, 6-8 blood samples were collected during 12 h intervals after reaching steady state. Polymyxin B concentration in serum was determined using a previously developed ELISA. Protein binding was assessed by rapid equilibrium dialysis. RESULTS: In 13 critically ill patients on ECMO who received polymyxin B, the median area under the concentration-time curve over 12 h (AUC0-12h) was 48.38 mg/h/L for the total drug and 14.08 mg/h/L for the free drug. The unbound fraction was 0.35. Total body clearance was 1.16 L/h. In non-ECMO patients, the median AUC0-12h was 34.7 mg/h/L and the median CL was 1.76 L/h. The volume of distribution was significantly lower in ECMO patients (19.7 versus 30.4 L, respectively). We found a moderate negative correlation between the ECMO blood flow rate and AUC0-12h, a strong negative correlation between SOFA score and polymyxin B clearance and a moderate correlation between polymyxin B clearance and renal function in ECMO patients. CONCLUSIONS: Currently recommended polymyxin B dosage regimens are sufficient for patients receiving ECMO and no dosage increase is required. In our study, polymyxin B exposure was higher in ECMO patients compared with the control group.

MicroRNAs as novel biomarkers for rivaroxaban therapeutic drug monitoring.

OBJECTIVES: The aim of this study is to assess micro-RNAs miR-142 and miR-39 as potential biomarkers for drug-monitoring of rivaroxaban among elderly patients with atrial fibrillation. METHODS: The study involved 57 patients with median (ME) age 87 years [80-94 years old] with nonvalvular atrial fibrillation admitted to a multidisciplinary hospital in Moscow. High-performance liquid chromatography with mass-spectrometry detection (HPLC-MS) was carried out to measure rivaroxaban concentrations. Carriership of CYP3A4 and ABCB1 was detected. MiRNA expression levels were measured. The activity of CYP3A4 isoenzyme was measured as the ratio of the concentrations of 6ß-hydroxycortisol and cortisol. RESULTS: The miR-142 expression levels of patients with CC allelic variant polymorphism ABCB1 3435 C>T (rs1045642) were significantly higher compared to CT and TT variants 31.69 ± 1.60 vs. 34.06 ± 1.66 vs. 33.16 ± 1.77 (p=0.021). Carriers of TT allelic variant polymorphism ABCB1 rs4148738 had a higher concentration of the 6-beta-hydroxycortisol in urine compared to CC and CT variants 3,467.35 ± 1,055.53 vs. 3,453.52 ± 1,516.89 vs. 2,593.30 ± 1,172.52 (p=0.029). As for CYP3A4*22, the carriers of CC allelic variant had higher prothrombin time 14.10 ± 2.17 vs. 11.87 ± 0.60 and INR 1.31 ± 0.20 vs. 1.1 ± 0.06 but lower Quick's value 74.52 ± 16.84 vs. 97.55 ± 10.54 (p=0.059). A positive correlation between the Ct miR-142 and the aPTT p=0.019 was noted. Also miR-142 has a correlation with Quick's value p=0.095. There is no statistically significant connection between miR-142 and miR-39 expression levels and the plasma concentration of rivaroxaban (b coefficient=-2.055, SE 3.952, p=0.605 and b coefficient=1.546, SE 9.887, p=0.876 in the linear regression model respectively). CONCLUSIONS: This study has assessed new potential biomarkers for rivaroxaban therapeutic drug monitoring: miR-142 and miR-39.

MicroRNAs as novel biomarkers for rivaroxaban therapeutic drug monitoring.

OBJECTIVES: The aim of this study is to assess micro-RNAs miR-142 and miR-39 as potential biomarkers for drug-monitoring of rivaroxaban among elderly patients with atrial fibrillation. METHODS: The study involved 57 patients with median (ME) age 87 years [80-94 years old] with nonvalvular atrial fibrillation admitted to a multidisciplinary hospital in Moscow. High-performance liquid chromatography with mass-spectrometry detection (HPLC-MS) was carried out to measure rivaroxaban concentrations. Carriership of CYP3A4 and ABCB1 was detected. MiRNA expression levels were measured. The activity of CYP3A4 isoenzyme was measured as the ratio of the concentrations of 6ß-hydroxycortisol and cortisol. RESULTS: The miR-142 expression levels of patients with CC allelic variant polymorphism ABCB1 3435 C>T (rs1045642) were significantly higher compared to CT and TT variants 31.69 ± 1.60 vs. 34.06 ± 1.66 vs. 33.16 ± 1.77 (p=0.021). Carriers of TT allelic variant polymorphism ABCB1 rs4148738 had a higher concentration of the 6-beta-hydroxycortisol in urine compared to CC and CT variants 3,467.35 ± 1,055.53 vs. 3,453.52 ± 1,516.89 vs. 2,593.30 ± 1,172.52 (p=0.029). As for CYP3A4*22, the carriers of CC allelic variant had higher prothrombin time 14.10 ± 2.17 vs. 11.87 ± 0.60 and INR 1.31 ± 0.20 vs. 1.1 ± 0.06 but lower Quick's value 74.52 ± 16.84 vs. 97.55 ± 10.54 (p=0.059). A positive correlation between the Ct miR-142 and the aPTT p=0.019 was noted. Also miR-142 has a correlation with Quick's value p=0.095. There is no statistically significant connection between miR-142 and miR-39 expression levels and the plasma concentration of rivaroxaban (b coefficient=-2.055, SE 3.952, p=0.605 and b coefficient=1.546, SE 9.887, p=0.876 in the linear regression model respectively). CONCLUSIONS: This study has assessed new potential biomarkers for rivaroxaban therapeutic drug monitoring: miR-142 and miR-39.