Organic anion transporter 2 (OATP2) is an uptake transporter located on the basolateral membrane of human hepatocytes. It mediates the transportation of various organic solutes including bilirubin and impacts bilirubin metabolism. It is encoded by the gene of solute carrier organic anion transporter family member 1B1 and the gene variants that inhibit hepatic bilirubin uptake function may reduce the normal functional level of bilirubin elimination and result in neonatal hyperbilirubinemia. In recent years, some studies have indicated that variants of SLCO1B1 are associated with neonatal jaundice. This article reviews the research advance in SLCO1B1 with respect to the structure and function and the relationship between SLCO1B1 mutations and neonatal jaundice.
Glucosephosphate Dehydrogenase Deficiency ; genetics ; Humans ; Infant, Newborn ; Jaundice, Neonatal ; genetics ; Organic Anion Transporters ; genetics ; Polymorphism, Genetic ; Solute Carrier Organic Anion Transporter Family Member 1b1 ; genetics

BACKGROUND: Several studies have focused on the association between the lipid-lowering efficacy of statins and the SLCO1B1 c.521T>C polymorphism; however, the results are conflicting. The effects of statins show significant variability between individuals. This meta-analysis aimed to investigate the effects of the SLCO1B1 c.521T>C polymorphism on the lipid-lowering effects of statins. METHODS: We systematically searched PubMed and Web of Science to screen relevant studies. Meta-analysis was performed to identify the association between SLCO1B1 c.521 polymorphisms and the lipid-lowering effects of statinson the basis of the standard mean difference (SMD) and 95% confidence intervals (CIs). Additionally, we checked for heterogeneity (I 2) among studies and evidence of publication bias. We obtained eight studies including 2,012 wild genotype (T/T) and 526 variant genotype (T/C and C/C) cases. RESULTS: No significant difference was observed in the lipid-lowering efficacy of statins between the wildand variant genotypes of SLCO1B1, with a pooled SMD of 0.03 (95% CI: -0.07-0.13). Furthermore, there was no significant effect in the meta-analyses of the variant heterozygote, homozygote, and Chinese populations. Subgroup meta-analysis indicated that the timerequired for the statin to take effectdid notsignificantly affect the association between lipid-lowering efficacy of statins and SLCO1B1 c.521T>C polymorphism. However, thewild genotype improved the lipid-lowering efficacy of simvastatin with a pooled SMD of -0.26 (95% CI: -0.47- -0.05). CONCLUSIONS: No significant association was detected between the lipid-lowering efficacy of statins and the SLCO1B1 c.521T>C polymorphism, with the exception of simvastatin.
Alleles ; Databases, Factual ; Genotype ; Humans ; Hydroxymethylglutaryl-CoA Reductase Inhibitors/*therapeutic use ; Hyperlipidemias/drug therapy/genetics ; Polymorphism, Single Nucleotide ; Solute Carrier Organic Anion Transporter Family Member 1b1/*genetics

OBJECTIVEMultiple genetic and environmental factors contribute to the onset of many human diseases, such as neonatal hyperbilirubinemia. OATP 1B1 is an important polymorphism gene which transmembrane transports unconjugated bilirubin(UCB). Genetic polymorphisms that affect the functionality of the protein may potentially lead to altered transport characteristics. The T521C/A388G polymorphism of this gene has been reported to considerably reduce the transporting property of drugs like pravastatin, and may be involved in the membrane translocation of bilirubin. Some studies have shown that OATP 1B1 mediates bilirubin uptake from blood into the liver, and the OATP 1B1 polymorphism is a likely mechanism explaining the differences of bilirubin level in peripheral blood. The aim of this study was to evaluate the relationship between OATP 1B1 polymorphisms and neonatal hyperbilirubinemia.

METHODSA total of 220 newborn infants with hyperbilirubinemia were recruited from Hunan Children Hospital from November 2008 to December 2009 according to the diagnostic criteria. Age and sex matched control subjects comprised of 200 unrelated, hyperbilirubinemia-free newborns. Biochemical and clinical data were collected from the case history. One ml venous blood samples in EDTA vials were taken from each subject and DNA was isolated from peripheral leukocytes by standard methods, preserved in 4°C. 1 - 2 ml venous blood samples were also taken for detecting the serum total bilirubin and direct bilirubin level by chemical oxidation method. OATP 1B1 T521C/A388G polymorphisms were determined using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Allele and genotype frequencies were compared between patients and control. The gene polymorphism and risk of disease were also analyzed. Serum total bilirubin, conjugated bilirubin and unconjugated bilirubin levels were compared between different OATP 1B1 T521C/A388G genotypes.

RESULTSAllele frequencies in patients and control population were in Hardy-Weinberg equilibrium (P > 0.05). Allele and genotype frequencies of the OATP 1B1 T521C polymorphism in patients were significantly different from the controls. The OATP 1B1 521C allele frequency was only 8.2% in patients, while reached 14.0% in the control group which was very close to the frequency of common Chinese people. However, the proportion of wild type genotypes was significantly higher than those of the controls, reached 84.1%. The 521 C allele and genotypes carrying 521 C allele illustrated low risk for neonatal hyperbilirubinemia (OR = 0.530, 95%CI = 0.328 - 0.857; OR = 0.541, 95%CI = 0.344 - 0.851). However, the frequencies of alleles and genotypes of SLCO1B1 A388G did not differ significantly from those of the controls, and this polymorphism did not influence susceptibility to such disease. Among the three OATP 1B1 A388G genotypes, the level of total serum bilirubin (TSB), direct bilirubin (DB) and unconjugated bilirubin (UCB) were significantly different. Values of TSB, DB and UCB were the highest in wild type subjects, lower in heterozygotes, and the lowest in mutant homozygotes. TSB and UCB in patients with wild type genotypes reached 602.5 µmol/L and 585.0 µmol/L respectively, nearly twice the average value of homozygous patients. While the TSB and UCB in homozygotes were below the average value of all patients, only 351.7 µmol/L and 338.8 µmol/L respectively.

CONCLUSIONSOur findings indicated that OATP 1B1 A388G polymorphism has a notable influence on the serum bilirubin level in neonatal hyperbilirubinemia patients. The OATP 1B1 521T allele may be a potential risk factor of such disease. OATP 1B1 T521C/A388G was an important polymorphism gene which related with neonatal hyperbilirubinemia. Future study should involve other polymorphisms of OATP 1B1, more candidate genes and environmental risk factors. It is also necessary to investigate their association with the severity and prognosis of this disease in order to elucidate the genetic pathogenesis of neonatal hyperbilirubinemia as a complex disease. This study should be repeated in a larger population and different ethnic groups.

Bilirubin ; blood ; Case-Control Studies ; Female ; Humans ; Hyperbilirubinemia, Neonatal ; genetics ; Infant, Newborn ; Male ; Organic Anion Transporters ; genetics ; Polymorphism, Restriction Fragment Length ; Solute Carrier Organic Anion Transporter Family Member 1b1

OBJECTIVETo provide guidance for the high-dose methotrexate (HD-MTX) treatment of pediatric acute lymphoblastic leukemia (ALL), and to understand the impact of SLCO1B1c.521T>C (rs4149056) variant on methotrexate (MTX) pharmacokinetics and clinical outcome in children with ALL.

METHODEighty-two children with ALL in Division of Hematology of Wuhan Children's Hospital from January 2008 to February 2013 were enrolled. All patients were genotyped for rs4149056 single nucleotide polymorphism (SNP) into wild-type group (TT genotype) and variant group (TC/CC genotype). According to the ALL-BFM 2000 protocol, all patients received intravenous infusion of MTX every ten days at 3 to 5 g/m(2). Leucovorin rescue was performed after 36 hours of the MTX administration and its dose was adjusted according to the MTX plasma concentration at 48 hours. The concentrations of MTX and its metabolite at 24, 48 and 72 h were determined by high performance liquid chromatography with solid phase extraction. Population pharmacokinetic parameters were estimated by the NLME software. The pharmacokinetics, toxicity and leucovorin rescue was compared. The relapse rate within 5 years and event-free survival were followed up.

RESULTEighty-two pediatric patients were classified into two groups: variant group including 20 TC genotype carriers and one CC genotype carrier, wild-type group included 61 patients with TT genotype. Compared with wild-type group, plasma concentration of MTX at 48 and 72 h increased significantly [48 h: (1.00±1.41) vs.(0.34±0.17) µmol/L, t=2.131, P=0.046; 72 h: (0.31±0.26) vs.(0.08±0.04) µmol/L; t=3.995, P=0.001]. Area under the concentration time curve (AUC48-∝) of MTX significantly increased in variant group [(23.18±19.91) vs.(5.66±2.01) h·µmol/L] (t=4.025, P=0.001). Time above the MTX safety threshold (TC>0.1 µmol/L) increased significantly in variant group [(95.3±22.0) vs.(67.1±7.5) h, t=5.880, P<0.001]. Rescue dosage of leucovorin in variant group was higher than that in wild-type group [(312.7±287.8) vs.(140.6±27.5) mg/m2, t=2.614, P=0.017]. The children carrying rs4149056 C allele suffered from a higher frequency of serious adverse effect [gastrointestinal toxicity: 33% (7/21) vs. 5% (3/61);hepatic toxicity: 24% (5/21) vs. 2% (1/61)]. The difference was statistically significant (χ2=9.275, 8.289, all P<0.05). Hospital stay of variant group was significantly longer than that of wild-type [(4.95±1.43) vs. (4.05±0.22) d, t=2.881, P=0.009]. The relapse rate within 5 years of variant group and wild-type group were 9% (2/21) and 13% (8/61), respectively. There were no significant differences in the event-free survival between the two groups (χ2=0.001, P=0.971).

CONCLUSIONThe SLCO1B1 c.521T>C variant was an important determinant of MTX pharmacokinetics. An appropriate leucovorin dose raise in variant group was beneficial to reducing the serious toxicity and did not affect the long-term clinical outcome.

Alleles ; Antineoplastic Combined Chemotherapy Protocols ; Asparaginase ; Child ; Daunorubicin ; Disease-Free Survival ; Genotype ; Humans ; Leucovorin ; administration & dosage ; Methotrexate ; administration & dosage ; pharmacokinetics ; Organic Anion Transporters ; genetics ; Polymorphism, Genetic ; Polymorphism, Single Nucleotide ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; drug therapy ; genetics ; Prednisone ; Solute Carrier Organic Anion Transporter Family Member 1b1 ; Treatment Outcome ; Vincristine

This study is to report the effect of OATP1B1 gene mutation in the 521T --> C in Chinese human on the pharmacokinetics of rosuvastatin and guide the reasonable clinical application of rosuvastatin by the feature of genetic polymorphism of OATP1B1. Plasma samples were determined with LC-MS: the analyte and internal standard pitavastatin were both analyzed by MS in the ESI, m/z was 480.0 for rosuvastatin and 420.0 for the IS, separately. Genotyping of OATP1B1 was determined with the method of polymerase chain reaction--amplification refractory mutation system targeted at 40 healthy volunteers and showed that there were 7 subjects with 521T --> C mutant, accounting to 17.5% of total and wild type homozygote accounted to 82.5%. It was found that there were significant differences between OATP1B1 mutation in the 521T --> C and wild type homozygote for rosuvastatin pharmacokinetic process in Chinese human. In contrast to OATP1B1 wild type group, OATP1B1 mutation group's absorption degree increased, elimination process decreased. The OATP1B1 mutation should be noted for guiding the reasonable application of rosuvastatin during its clinical use.
Asian Continental Ancestry Group ; genetics ; Exons ; Fluorobenzenes ; blood ; pharmacokinetics ; Genotype ; Humans ; Hydroxymethylglutaryl-CoA Reductase Inhibitors ; blood ; pharmacokinetics ; Male ; Organic Anion Transporters ; genetics ; Point Mutation ; Polymorphism, Single Nucleotide ; Pyrimidines ; blood ; pharmacokinetics ; Rosuvastatin Calcium ; Solute Carrier Organic Anion Transporter Family Member 1b1 ; Sulfonamides ; blood ; pharmacokinetics