title: C3435T polymorphism in the MDR1 gene affects the enterocyte expression level of CYP3A4 rather than Pgp in recipients of living-donor liver transplantation.
abstract: The bioavailability of structurally unrelated drugs is limited by active secretion via the multidrug resistance gene (MDR1) product P-glycoprotein (Pgp) from enterocyte into lumen as well as intestinal metabolism by cytochrome P450 IIIA4 (CYP3A4). In the present study, we analyzed whether genetic polymorphism of the MDR1 had some influence on the intestinal expression levels of Pgp and CYP3A4 and the tacrolimus concentration/dose ratio over the first postoperative days in recipients of living-donor liver transplantation (LDLT). Genotyping assays were performed for the major 10 polymorphisms in the MDR1 gene by the polymerase chain reaction-restriction enzyme length polymorphism method. The allele frequencies of variations at five positions were almost comparable with those in the former studies in Caucasians and Japanese, but there was no variation at the other five positions. Although no polymorphism correlated with the intestinal expression of MDR1 mRNA or the tacrolimus concentration/dose ratio in the LDLT recipients, the C3435T polymorphism significantly affected the intestinal expression level of CYP3A4 mRNA as follows; 3435C/C>3435C/T (P < 0.05 vs. 3435C/C)>3435T/T (P < 0.01 vs. 3435C/C). Therefore, the identified polymorphisms including C3435T in the MDR1 gene were indicated to have no influence on the intestinal expression level of Pgp or the tacrolimus concentration/dose ratio in the recipients of LDLT. On the other hand, the C3435T polymorphism of MDR1 was suggested to correlate with the enterocyte expression of CYP3A4 rather than Pgp linking unknown genetic variation in CYP3A4 gene.
authors.affiliation: Department of Pharmacy, Faculty of Medicine, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Goto
authors.forename: Satohiro
authors.initials: S
authors.lastname: Masuda
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Saito
authors.forename: Shinji
authors.initials: S
authors.lastname: Uemoto
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kiuchi
authors.forename: Koichi
authors.initials: K
authors.lastname: Tanaka
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Inui
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics* / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D020895:Enterocytes / Q000201:enzymology*; D005260:Female; D005787:Gene Frequency; D019450:Genes, MDR / Q000235:genetics*; D006801:Humans; D007166:Immunosuppressive Agents / Q000493:pharmacokinetics / Q000627:therapeutic use; D007223:Infant; D007413:Intestinal Mucosa / Q000378:metabolism; D016031:Liver Transplantation; D019520:Living Donors; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D011379:Prognosis; D012333:RNA, Messenger / Q000378:metabolism; D016559:Tacrolimus / Q000493:pharmacokinetics / Q000627:therapeutic use
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D017931:DNA Primers; D007166:Immunosuppressive Agents; D012333:RNA, Messenger; D003577:Cytochrome P-450 Enzyme System; C104464:CYP3A protein, human; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; D016559:Tacrolimus