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Fexofenadine is useful in various allergic disease treatment.However,the pharmacokinetic variability information and quantitative factor identification of fexofenadine are very lacking.This study aimed to verify the validity of previously proposed genetic factors through fexofenadine population pharmaco-kinetic modeling and to explore the quantitative correlations affecting the pharmacokinetic variability.Polymorphisms of the organic-anion-transporting-polypeptide(OATP)1B1 and 2B1 have been proposed to be closely related to fexofenadine pharmacokinetic diversity.Therefore,modeling was performed using fexofenadine oral exposure data according to the OATP1B1-and 2B1-polymorphisms.OATP1B1 and 2B1 were identified as effective covariates of clearance(CL/F)and distribution volume(V/F)-CL/F,respectively,in fexofenadine pharmacokinetic variability.CL/F and average steady-state plasma con-centration of fexofenadine differed by up to 2.17-and 2.20-folds,respectively,depending on the OATP1B1 polymorphism.Among the individuals with different OATP2B1 polymorphisms,the CL/F and V/F differed by up to 1.73-and 2.00-folds,respectively.Ratio of the areas under the curves following single-and multiple-administrations,and the cumulative ratio were significantly different between OATP1B1-and 2B1-polymorphism groups.Based on quantitative prediction comparison through a model-based approach,OATP1B1 was confirmed to be relatively more important than 2B1 regarding the degree of effect on fexofenadine pharmacokinetic variability.Based on the established pharmacokinetic-pharmacodynamic relationship,the difference in fexofenadine efficacy according to genetic poly-morphisms of OATP1B1 and 2B1 was 1.25-and 0.87-times,respectively,and genetic consideration of OATP1B1 was expected to be important in the pharmacodynamics area as well.This population phar-macometrics study will be a very useful starting point for fexofenadine precision medicine.
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Fibrates are a class ofmedication that mainly lowers theblood triglyceride levels. Theyreduce the LDL andincrease the levels of HDL C, in the blood.Clofibrate,the first member to bediscovered in 1962, and introduced in USA in 1967, is withdrawnin 2002, due to unexplained hepatomegaly,hepato-toxicity and possible risk of hepatic cancer. Other fibrates are introduced in the late 1970s and early1980s, such as gemfibrozil in the United States and bezafibrate and ciprofibrate in Europe. Their lipid lowering effects are found to decrease CVS risk , progression of atherosclerosis and metabolic syndrome, macrovascular and microvascular diabetic complications like stroke, myocardial infarction, peripheral vascular diseaseand diabeticretinopathy .Various clinical trials like VA-HIT trial (Veterans Affairs High-Density LipoproteinCholesterol Intervention Trial) , FIELD trail. (the Fenofibrate Intervention and Event Lowering in Diabetes) Helsinki Heart Study,ACCORD -Lipid trial (The lipid component of the Action to Control Cardiovascular Risk in Diabetes trial ) and BIP (Bezafibrate Infarction Prevention Study) trial andangiography trials, like LOCAT(LopidCoronary Angiography Trial) and BECLAIT(Bezafibrate Coronary Atherosclerosis Intervention Trial)demonstrated thebeneficial effects of gemfibrozil and fenofibrate.Their mechanism of action remained obscure for three decades,ie till 1990s, when theirmode of actionwas found. The Mechanism of action of fibrates include limitation of substrate availability for triglyceride synthesis in the liver, promotion of the action of lipoprotein lipase, (LPL)modulation of low density lipoprotein receptor/ligand interaction and stimulation of reverse cholesterol transport The biochemical and molecular mechanisms involvingthevariousenzymes like LCAT (Lecithin-cholesterol acyl transferase)andCYP7A1 etc. (cholesterol 7-alpha-monooxygenase or cytochromeP450 7A1 (CYP7A1)) , transporters like ABC , CETP (ATP-binding cassette transporter, Cholesterol ester binding protein) and NTCP,OATP (Na+-dependent taurocholate transporter/ organic anion transporters) . These are the.) andnuclear factors like LXR, PPAR alfa etc. (liver orphan receptorα , and peroxisome proliferative nuclear factor) , in relation to the mechanismsof action of fibrates are discussed . Areas of current interests in literature are briefed.
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The incidence of polypharmacy-which can result in drug-drug interactions-has increased in recent years. Drug-metabolizing enzymes and drug transporters are important polypharmacy modulators. In this study, the effects of bosentan and rifampin on the expression and activities of organic anion-transporting peptide (OATP) and cytochrome P450 (CYP450) 2C9 and CYP3A4 were investigated in vitro. HEK293 cells and primary human hepatocytes overexpressing the target genes were treated with bosentan and various concentrations of rifampin, which decreased the uptake activities of OATP transporters in a dose-dependent manner. In primary human hepatocytes, CYP2C9 and CYP3A4 gene expression and activities decreased upon treatment with 20 μM bosentan+200 μM rifampin. Rifampin also reduced gene expression of OATP1B1, OATP1B3, and OATP2B1 transporter, and inhibited bosentan influx in human hepatocytes at increasing concentrations. These results confirm rifampin- and bosentan-induced interactions between OATP transporters and CYP450.
Subject(s)
Humans , Cytochrome P-450 CYP2C9 , Cytochrome P-450 CYP3A , Cytochrome P-450 Enzyme System , Cytochromes , Gene Expression , HEK293 Cells , Hepatocytes , In Vitro Techniques , Incidence , Organic Anion Transporters , Polypharmacy , RifampinABSTRACT
Objective: To explore the effect of arecoline hydrobromide (AH) on the expression of rat hepatic and renal transporters. Methods: The effect of AH on the mRNA expression of 13 hepatic and renal transporters was studied after orally giver AH (0.8, 4, and 20 mg/kg/d) to rats for 21 d. Results: The results from the real-time PCR indicated that, AH treatment at low dose significantly decreased the mRNA levels of hepatic MRP2 and MDR1A, while significantly increased renal MRP5 mRNA level. On the other hand, AH treatment at high dose significantly inhibited the mRNA expression of hepatic OCT2, OAT2, OCTN2, OATP1A1, OATP1A4, OATP2B1, MRP2, and MDR1A, as well as renal MRP2, BCRP, and MDR1A. However, the mRNA expression of renal OCTN2, OATP1A1, OATP1A4, and MRP5 were significantly up-regulated following the treatment of high dose of AH. And the AH-induced effect on the above transporters was dose dependent in some extent. Conclusion: Due to the drug interaction caused by the alteration in expression and function of hepatic and renal transporters, it is suggested that the betel nut addicts should be paid more attention in case of adverse drug interactions.
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The study was designed to explore the drug-drug interactions mechanisms mediated by OATP1B1 between traditional Chinese medicine Danshensu and rosuvastatin. First, the changes of rosuvastatin pharmacokinetics were investigated in presence of Danshensu in rats. Then, the primary rat hepatocytes model was established to explore the effects of Danshensu on the uptake of rosuvastatin by hepatocytes. Finally, HEK293T cells with overexpression of OATP1B1*1a and OATP1B1*5 were established using a lentiviral delivery system to explore the effects of Danshensu on the uptake of rosuvastatin. Rosuvastatin pharmacokinetic parameters of Cmax, AUC0-t, AUC0-∞ were increased about 123%, 194% and 195%, by Danshensu in rats, while the CLz/F value was decreased by 60%. Uptake of rosuvastatin in the primary rat hepatocytes was decreased by 3.13%, 41.15% and 74.62%, respectively in the presence of 20, 40 and 80 μmol·L-1 Danshensu. The IC50 parameters was (53.04 ± 2.43) μmol·L-1. The inhibitory effect of Danshensu on OATP1B1 mediated transport of rosuvastatin was related to the OATP1B1 gene type. In OATP1B1*5-HEK293T mutant cells, transport of rosuvastatin were reduced by (39.11 ± 4.94) % and (63.61 ± 3.94) %, respectively, by Danshensu at 1 and 10 μmol·L-1. While transport of rosuvastatin was reduced by (8.22 ± 2.40) % and (11.56 ± 3.04) % and in OATP1B1*1a cells, respectively. Danshensu significantly altered the pharmacokinetics of rosuvastatin in rats, which was related to competitive inhibition of transport by OATP1B1. Danshensu exhibited a significant activity in the inhibition of rosuvastatin transport by OATP1B1*5-HEK293T, but not by OATP1B1*1a, suggesting a dependence on OATP1B1 sequence.
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MicroRNAs (miRNAs) are a family of non-coding RNA that are able to adjust the expression of many proteins, including ATP-binding cassette transporter and organic cation transporter. We sought to evaluate the effect of miR-511 on the regulation of OATP1B1 expression by free fatty acids. When using free fatty acids to stimulate Chang liver cells, we found that the expression of miR-511 increased significantly while the expression of OATP1B1 decreased. We also proved that SLCO1B1 is the target gene of miR-511 with a bioinformatics analysis and using the dual luciferase reporter assay. Furthermore, the expressions of SLCO1B1 and OATP1B1 decreased if transfecting Chang liver cells with miR-511, but did not increase when transfecting the inhibitors of miR-511 into steatosis cells. Our study indicates that miR-511 may play an important role in the regulation of OATP1B1 expression by free fatty acids.
Subject(s)
Humans , Computational Biology , Fatty Acids, Nonesterified , Liver , Luciferases , MicroRNAs , RNA, UntranslatedABSTRACT
Objective To establish a patient-derived gastric cancer xenograft( PDX) model in nude mice and to in-vestigate the application of near infrared fluorescent ( NIRF) dye IR-783 in in vivo imaging of gastric cancer xenograft mod-els.Methods Fresh human gastric cancer tissue was taken and transplanted into the subrenal capsule of nude mice to es-tablish the xenograft model.When the transplanted tumors grew,took part of the tumor tissue to do HE staining and compare the structural characteristics with the primary tumor.Another portion of the tumor was xenografted into nude mice subcutane-ously.Twenty days later,the tumor-bearing mice were injected intraperitoneally with IR-783 dye (10μM) in a dose of 100 mg/20 g.The intensity of the tumor image was monitored by optical NIRF imaging.The correction between tumor volume and fluorescence intensity was analyzed.Finally,the expression of OATP1B3 and HIF1αin the xenografted tumor tissue was detected by immunohistochemistry.Results We successfully established three patient-derived xenograft ( PDH) models of human gastric cancer.The transplanted tumor tissues maintained the histological characteristics of the primary tumor well.NIRF signal can be detec ted in subrenal capsule of the xenografted nude mice.The correlation between tumor size and fluorescence intensity in the PDX models reached higher than 98%.Strong positive expressions of HIF1αand OATP1B3 in the tumor tissues were detected.Conclusions NIRF dye IR-783 can be specifically accumulated at the tumor site,therefore, can be used to detect PDX in vivo early.The tumor targeting property may be related to the expression of OATP1B3 and HIF1α.
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Objective To study the relationship between the OATP1B1 521T ＞ C genetic polymorphism and essential hypertension.Methods 164 essential hypertension subjects and 159 normotensive subjects were detected by the TaqMan-MGB probe real-time fluorescence quantitative PCR,and the results were compared with those of DNA sequencing.Results The frequencies of T/C genotype and C allele of OATP1B1 521T ＞ C gene of the essential hypertension subjects were obviously lower than those of the normotensive subjects(T/C genotype:0.16 vs 0.25,P ＜0.05 ;C allele:0.10 vs 0.17,P ＜0.05),The difference was significant.Binary logistic stepwise regression analysis was used for evaluatine the risk factors of essential hypertension,there was significant relationship between OATP1 B1 52IT ＞ C gene polymorphism and essential hypertension.Conclusion The SLCO1 B1 521T ＞ C variant was common in Chinese essential hypertension population,but the difference of frequency of SLCO1B1 52IT ＞ Cmuton between the essential hypertension patients and the normotensive controls was of obviously statistical significance,which indicates that the SLCO1B1521T ＞ C variant maybe associate with essential hypertension.
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Thyroid hormones play important roles in growth, development, and metabolism of various cells and tissues. It has been assumed for a long time that thyroid hormones are lipophilic and enter cells by passive diffusion, but it has become increasingly clear that cellular uptake and efflux of thyroid hormones are mediated by transporters. The discovery of these thyroid hormone transporters will lead to a better understanding of the tissuespecific regulation of thyroid hormones.
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Objectives: This study aimed to determine the prevalence of four variants of organic anion transporter polypeptide 2 (OATP2) gene, and their association with severe hyperbilirubinemia. Design: Observational study. Setting: A tertiary university unit. Patients: Term infants of Chinese descent. Methods: 175 infants, consisting of 65 admitted for treatment of severe hyperbilirubinemia (with serum bilirubin levels > 250 mmol/L at age 1-2 days or > 300 μmol/L at age ≥ 3 days) and 110 randomly selected inborn infants without severe hyperbilirubinemia during their fi rst month of life, were recruited. Their blood samples were subjected to sequencing analysis of exon 4 and exon 5 of OATP2 gene for detection of c.388A>G, c.521T>C, c.571T>C and c.597C>T variants. Results: The c.388A>G variant was the most common, and the c.521 T>C was least common, being present in 90.9% and 26.9% of the infants, respectively. Forward logistic regression analysis showed that the only signifi cant risk factors associated with severe hyperbilirubinemia among these Chinese infants were: exclusive breast feeding (adjusted odds ratio (OR) = 12.5, 95% C.I.: 2.9, 53.4; p=0.001), infants with homozygous 211 variant of the UDPG 1A1 gene (adjusted OR = 37.7, 95% C.I.: 4.4, 324.1; p=0.001), and G6PD enzyme level <8.5 IU/g Hb (adjusted OR = 7.3, 95% C.I.: 3.1, 17.5; p<0.00001). Gestational age, G6PD mutation status, actual G6PD enzyme level, and the 4 variants of the OATP2 gene mutation were not signifi cant risk factors. Conclusion: Variants of OATP2 gene were not signifi cant risk factors associated with severe hyperbilirubinemia in Malaysian Chinese infants.
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Objective To investigate the expression variation of kidney OATP-3 in rats relating to rocuronium metabolism in anhepatic phase and to primarily explain the reason of extrahepatic metabolism characters of rocuronium. Methods Twelve rats were distributed to 2 groups randomly with 6 in each: Group A (control group) and Group B in which the hepatic portal devascularization was performed for 60 min. Kidney tissues of the rats were taken. oatp-3 mRNA was detected by RT-PCR and OATP-3 protein by Western blotting. Results The expression levels of kidney OATP-3 mRNA and protein in Group B were significantly higher than those in Group A(P