title: Pharmacokinetics and response to pravastatin in paediatric patients with familial hypercholesterolaemia and in paediatric cardiac transplant recipients in relation to polymorphisms of the SLCO1B1 and ABCB1 genes.
abstract: OBJECTIVE
  Our aim was to investigate associations between the single nucleotide polymorphisms (SNPs) in the SLCO1B1 (encoding OATP1B1) and ABCB1 (encoding P-glycoprotein) genes with the pharmacokinetics and efficacy of pravastatin in children with heterozygous familial hypercholesterolaemia (HeFH) and in paediatric cardiac transplant recipients.
  
  
  METHODS
  Twenty children with HeFH (aged 4.9-15.6 years) and 12 cardiac transplant recipients (aged 4.4-18.7 years and receiving triple immunosuppressive medication) who had participated in previous pharmacokinetic and pharmacodynamic studies with pravastatin were genotyped for the -11187G > A and 521T > C SNPs in the SLCO1B1 gene and for the 2677G > T/A and 3435C > T SNPs in the ABCB1 gene.
  
  
  RESULTS
  Two HeFH patients with the -11187GA genotype had a 81% lower peak plasma pravastatin concentration (Cmax) (difference in means -13.9 ng ml(-1), 95% CI -21.1, -6.7; P < 0.001) and a 74% smaller area under the plasma concentration-time curve (AUC0, infinity) (-25.3 ng ml(-1) h, 95% CI -35.6, -15.0; P < 0.0001) and significantly greater increase in high density lipoprotein (HDL) cholesterol after 2 months treatment with pravastatin than patients with the reference genotype. No significant differences were seen in the pharmacokinetics or effects of pravastatin between HeFH patients with the SLCO1B1 521TC and 521TT genotypes. The cardiac transplant recipients with the SLCO1B1 521TC genotype (n = 3) had a 46% lower Cmax (-67.7 ng ml(-1), 95% CI -135.7, 0.3; P = 0.055) and 62% lower AUC(0,24 h) (-228.5 ng ml(-1) h, 95% CI -402.7, -54.3; P = 0.016) and a shorter half-life (t1/2) (0.9 +/- 0.1 vs. 1.3 +/- 0.4 h, P = 0.015) of pravastatin than those with the reference genotype. Decreases in total and low-density lipoprotein cholesterol by pravastatin were significantly smaller, and the increase in HDL-cholesterol was greater in the transplant recipients with the 521TC genotype compared with patients with the 521TT reference genotype.
  
  
  CONCLUSIONS
  In children with HeFH and in paediatric cardiac transplant recipients receiving immunosuppressive medication, the -11187G > A and SLCO1B1 521T > C SNPs were associated with decreased plasma concentrations of pravastatin. These differences are opposite to those seen previously in healthy adults. The mechanisms underlying these phenomena are unclear and warrant further study.
authors.affiliation: Hospital for Children and Adolescents, University of Helsinki, Helsinki, Finland.
authors.forename: Mia
authors.initials: M
authors.lastname: Hedman
authors.forename: Marjatta
authors.initials: M
authors.lastname: Antikainen
authors.forename: Christer
authors.initials: C
authors.lastname: Holmberg
authors.forename: Mikko
authors.initials: M
authors.lastname: Neuvonen
authors.forename: Michel
authors.initials: M
authors.lastname: Eichelbaum
authors.forename: Kari T
authors.initials: KT
authors.lastname: Kivistö
authors.forename: Pertti J
authors.initials: PJ
authors.lastname: Neuvonen
authors.forename: Mikko
authors.initials: M
authors.lastname: Niemi
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D005838:Genotype; D016027:Heart Transplantation; D006801:Humans; D006938:Hyperlipoproteinemia Type II / Q000188:drug therapy* / Q000235:genetics; D027381:Liver-Specific Organic Anion Transporter 1; D008297:Male; D027361:Organic Anion Transporters / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics; D017035:Pravastatin / Q000493:pharmacokinetics / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D027381:Liver-Specific Organic Anion Transporter 1; D027361:Organic Anion Transporters; C503999:SLCO1B1 protein, human; D017035:Pravastatin