Search results for "CYP3A5"

Pharmacogenetic considerations for optimizing tacrolimus dosing in liver and kidney transplant patients

2013

The introduction of tacrolimus in clinical practice has improved patient survival after organ transplant. However, despite the long use of tacrolimus in clinical practice, the best way to use this agent is still a matter of intense debate. The start of the genomic era has generated new research areas, such as pharmacogenetics, which studies the variability of drug response in relation to the genetic factors involved in the processes responsible for the pharmacokinetics and/or the action mechanism of a drug in the body. This variability seems to be correlated with the presence of genetic polymorphisms. Genotyping is an attractive option especially for the initiation of the dosing of tacrolim…

Genetics of the variable expression of CYP3A in humans.

2004

CYP3A isozymes participate in the metabolism of 45-60% of currently used drugs and of a variety of other compounds such as steroid hormones, toxins, and carcinogens. The CYP3A expression status is a major determinant of drug efficacy and safety, and it may also affect an individual's predisposition to certain cancers. The inter- and intraindividual expression of CYP3A is variable because of a complex interplay between genetic and environmental factors. Markers predictive of the individual CYP3A activity could improve therapies with CYP3A substrates by personalised dose adjustments, but their development has been slower than for other drug-metabolizing enzymes. Here we summarize the recent p…

Genetic signature consistent with selection against the CYP3A4*1B allele in non-African populations.

2005

Cytochrome P450 3A enzymes (CYP3A) play a major role in the metabolism of steroid hormones, drugs and other chemicals, including many carcinogens. The individually variable CYP3A expression, which remains mostly unexplained, has been suggested to affect clinical phenotypes. We investigated the CYP3A locus in five ethnic groups. The degree of linkage disequilibrium (LD) differed among ethnic groups, but the most common alleles of the conserved LD regions were remarkably similar. Non-African haplotypes are few; for example, only four haplotypes account for 80% of common European Caucasian alleles. Large LD blocks of high frequencies were suggestive of selection. Accordingly, European Caucasia…

Meta-analysis and systematic review of the effect of the donor and recipient CYP3A5 6986A>G genotype on tacrolimus dose requirements in liver tran…

2013

Objective A meta-analysis was carried out of publishedstudies on the effect of the CYP3A5 6986A>Gpolymorphism in liver donors and transplant recipientson tacrolimus pharmacokinetics.Methods Cohort studies that evaluated the relationshipbetween the CYP3A5 polymorphism in liver donors andtransplant recipients and tacrolimus, trough bloodconcentration normalized for the daily dose (C) perkilogram body weight (D) (C/D, ng/ml/mg/kg/day) up to1 year after transplantation, were included. Data were notrestricted by patient age or the language or journal ofpublication. A literature search was conducted using theCochrane Library, MEDLINE, EMBASE, and grey literature,and articles published up to 24 Ap…

Unusual high dose of tacrolimus in liver transplant patient, a case report.

2012

Case We describe the case of a liver transplant patient who had great difficulty in reaching the desired trough blood levels despite the use of high dose tacrolimus. The patient was homozygous for the CYP3A5*3 allele. However, the respective donor carried the wild-type CYP3A5*1/*1 genotype. Regarding ABCB1 SNPs at exon 21 and 26, the patient showed the 2677GT and 3435CC genotypes. For the corresponding donor we observed the 2677GG and 3435CC wild-type genotypes. One, two and three weeks after transplantation the patient received daily 0.219, 0.287 and 0.273 mg/kg of tacrolimus, respectively. However, the corresponding tacrolimus trough blood levels were of 4.6, 5.6 and 6.1 ng/mL. The tacrol…

THE EFFECT OF CYP3A5 AND ABCB1 SINGLE NUCLEOTIDE POLYMORPHISMS ON TACROLIMUS DOSE REQUIREMENTS IN CAUCASIAN LIVER TRANSPLANT PATIENTS

2008

The effect of CYP3A5 and ABCB1 single nucleotide polymorphisms on tacrolimus dose requirements in Caucasian liver transplant patients

2008

Background: Tacrolimus is a substrate of cytochrome P-450 (CYP) 3A enzyme and of the drug transporter ABCBl. We have investigated the effects of possible relevant CYP3A5 and ABCBl single nucleotide polymorphisms (SNPs) present in both donors and recipients on tacrolimus blood levels achieved in a population of 32 Caucasian liver transplant patients. Material/Methods: At 1, 3 and 6 months after transplantation, tacrolimus doses (mg/kg/day) and trough blood levels (C0) were determined. Polymerase chain reaction followed by restriction fragment length polymorphism analysis was used for gen-otyping CYP3A5*3 [6986A>G] as well as ABCBl at exons 21 [2677G>T] and 26 [3435C>T]. Results:87.5…

Pharmacogenetic Study of ABCB1 and CYP3A5 Genes During the First Year Following Heart Transplantation Regarding Tacrolimus or Cyclosporine Levels

2011

Pharmacogenetics explains part of the interindividual variability in drug responses. Many published works about the effects of single nucleotide polymorphisms (SNPs) on immunosuppressive drug blood levels present contradictory results. We evaluated the SNPs in ABCB1 (glycoprotein P) and CYP3A5 (metabolic enzyme) genes, seeking correlate them with tacrolimus or cyclosporine levels during the first year after heart transplantation. One blood sample was obtained from each of 41 patients: 26 treated with cyclosporine and 15 with tacrolimus. We characterize the SNPs rs1045642, 1128503, 2032582, 2235013, 2235033, 2229109, 3213619, 9282564 in ABCB1 and rs10264272, 776746 in CYP3A5 genes using the …

Impacto de la farmacogenética en la inmunosupresión con Tacrólimus en el trasplante hepático y renal

2017

Los trasplantes de órganos sólidos, en especial el trasplante hepático y renal, han permitido aumentar la supervivencia de la población, lo que se ha potenciado con el desarrollo de las técnicas quirúrgicas y de la inmunosupresión farmacológica, dentro de los que destaca la aparición de los inhibidores de la calcineurina (InC), especialmente tacrólimus. A pesar de estos avances, persisten cifras importantes de rechazo agudo y de toxicidad aguda y crónica precisamente por el uso de los InC que pueden dificultar la mejoría de la supervivencia y la calidad de vida de los pacientes trasplantados. Para reducir estos riesgos se han implementado intervenciones para mejorar la dosificación de los I…

2017

Abstract Background Results on the association between prenatal exposure to methylmercury (MeHg) and child neuropsychological development are heterogeneous. Underlying genetic differences across study populations could contribute to this varied response to MeHg. Studies in Drosophila have identified the cytochrome p 450 3A (CYP3A) family as candidate MeHg susceptibility genes. Objectives We evaluated whether genetic variation in CYP3A genes influences the association between prenatal exposure to MeHg and child neuropsychological development. Methods The study population included 2639 children from three birth cohort studies: two subcohorts in Seychelles (SCDS) (n = 1160, 20 and 30 months of…