ABCB1
ATP-dependent translocase ABCB1 (ATP-binding cassette sub-family B member 1) (Multidrug resistance protein 1) (EC 7.6.2.2) (P-glycoprotein 1) (Phospholipid transporter ABCB1) (EC 7.6.2.1) (CD243 antigen) [MDR1] [PGY1]
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Whether age and inter-individual variability of pharmacogenetics are risk factors for paclitaxel-induced peripheral neuropathy (PIPN) is inconclusive. This study was conducted to evaluate the influence of previously investigated single nucleotide polymorphisms (SNPs) and age, using genotype data from a prospective study of paclitaxel-related toxicity in Japanese patients with breast cancer. Peripheral blood mononuclear cells from 127 Japanese women with breast cancer who received weekly adjuvant paclitaxel were used to genotypes SLCO1B3 T334G (rs4149117), CYP2C8 A1196G (rs10509681), ABCB1 C1236T (rs1128503), ABCB1 G2677T/A (rs2032582), and ABCB1 C3435T (rs1045642). Genotypic and clinical factors were investigated for associations with PIPN. Of the five SNPs evaluated, no SNPs were significantly associated with grade 2 or higher PIPN. However, ABCB1 1236 TT showed a trend to associate with grade 2 or higher PIPN compared to ABCB1 CT/CC (odds ratio 2.1, 95% CI 0.991-4.548, p = 0.051). In subgroup analysis, patients ≥60 years old with an ABCB1 1236 TT had a higher incidence of ≥grade 2 PIPN compared to patients with CT or CC genotype (p = 0.027). On multivariable analysis, age ≥60 years and the ABCB1 1236 TT showed a significant association with ≥grade 2 PIPN (p = 0.005 and p = 0.034, respectively). ABCB1 1236 TT genotype and older age might be a predictor of PIPN, which diminishes quality of life of cancer survivors.
MeSH Terms
- ATP Binding Cassette Transporter, Subfamily B
- Adult
- Aged
- Aging
- Antineoplastic Agents, Phytogenic
- Asian Continental Ancestry Group
- Breast Neoplasms
- Cytochrome P-450 CYP2C8
- Female
- Genotype
- Humans
- Incidence
- Middle Aged
- Organic Anion Transporters, Sodium-Independent
- Paclitaxel
- Peripheral Nervous System Diseases
- Pharmacogenetics
- Polymorphism, Single Nucleotide
- Predictive Value of Tests
- Prospective Studies
- Sensory Receptor Cells
- Solute Carrier Organic Anion Transporter Family Member 1B3
Keywords
- ABCB1
- CYP2C8
- Older age
- Paclitaxel-induced peripheral neuropathy
- SLCO1B3
The activity of several key enzymes involved in the metabolism of many drugs is subject to change closely related to the age of patients. This possibility must also be considered in the case of tacrolimus, the most important calcineurins inhibitor, which is widely used in pediatric kidney transplantation. As well as in the liver and intestine, some of the enzymes involved in the metabolism of tacrolimus were also isolated in the peripheral blood mononuclear cells (PBMCs), where also appear to play an important regulatory action. Therefore, the influence of some external factors on the expression of specific mRNA can be determined noninvasively. The correlation between the levels of mRNA specific for key enzymes SXR, CYP3A and ABCB1 involved in the metabolism of tacrolimus was evaluated in PBMCs obtained from a selected population of 29 young kidney transplant recipients. A possible correlation between the expression of these specific mRNAs and tacrolimus pharmacokinetics was also investigated. The patients' age and their blood concentrations of SXR mRNA were directly correlated with the expression of CYP3A4, CYP3A5 mRNAs, but not of ABCB1 mRNA in the PBMCs. tacrolimus-normalized daily dose was strongly correlated with patient's age and multivariable regression indicates the CYP3A4-specific mRNA as the sole independent variable influencing tacrolimus concentration-to-dose ratio. Aging and SXR mRNA significantly affect the expression of CYP3A4- and CYP3A5-specific mRNA as measured by their concentration in PBMC.
MeSH Terms
- ATP Binding Cassette Transporter, Subfamily B
- Adolescent
- Aging
- Cytochrome P-450 CYP3A
- Female
- Humans
- Immunosuppressive Agents
- Kidney Transplantation
- Male
- Monocytes
- Pregnane X Receptor
- RNA, Messenger
- Receptors, Steroid
- Tacrolimus
Keywords
- ABCB1
- CYP3A4
- CYP3A5
- SXR
- mRNA
- pediatric kidney transplant
- peripheral blood mononuclear cells
- tacrolimus
ATP-binding cassette (ABC) transporters play an increasing role in the understanding of pathologic peptide deposition in neurodegenerative diseases (NDs), such as Alzheimer's and Parkinson's. To describe the location of the most important ABC transporters for NDs in human brain tissue, we investigated ABCB1 and ABCC1 immunohistologically in the adult human brain and pituitary. Both transporters have similar but not identical expression patterns. In brain regions with an established blood-brain barrier (BBB), ABCB1 and ABCC1 were ubiquitously expressed in endothelial cells of the microvasculature and in a subset of larger blood vessels (mostly venules). Remarkably, both transporters were also found in fenestrated capillaries in circumventricular organs where the BBB is absent. Moreover, ABCB1 and ABCC1 were also expressed in various non-endothelia cells such as pericytes, astrocytes, choroid plexus epithelia, ventricle ependymal cells, and neurons. With regard to their neuronal expression it was shown that both transporters are located in specific nerve cell populations, which are also immunopositive for three putative cell markers of purinergic cell signalling, namely 5'-nucleotidase, adenosine deaminase and nucleoside triphosphate diphosphohydrolase-2. Therefore, we speculate that neuronal expression of ABCB1 and ABCC1 might be linked to adenosinergic/purinergic neuromodulation. Lastly, both transporters were observed in multiple adenohypophyseal cells.
MeSH Terms
- ATP Binding Cassette Transporter, Subfamily B
- Adult
- Aging
- Blood-Brain Barrier
- Female
- Gene Expression Regulation
- Humans
- Male
- Middle Aged
- Multidrug Resistance-Associated Proteins
- Nerve Tissue Proteins
- Pituitary Gland
Keywords
- ABC transporters
- ATP-binding cassette sub-family B member 1 (ABCB1)
- ATP-binding cassette sub-family C member 1 (ABCC1)
- Blood–brain barrier
- Circumventricular organs
- Human brain
- Human pituitary
- Neurons
- Purinergic signalling
Tacrolimus is one of the commonly used immunosuppressive drugs for pediatric heart transplants. Large variation exists in pharmacokinetics during the direct post-transplant period, resulting in an increased risk of adverse events. Limited data are available on the interaction of age, CYP3A5 and ABCB1 genotype, and disease severity on the variation in disposition and outcome in pediatric heart transplant recipients. We studied the relationship between age and CYP3A5 and ABCB1 genotype and the Pediatric Risk of Mortality (PRISM) score on tacrolimus dose (mg/kg), steady-state trough concentrations, and concentration/dose ratio, as well as rejection and renal function for 14 days after heart transplant in children. Tacrolimus was administered to 39 children (median age, 6.0 years) after transplant. A correlation was found between the age at the time of transplant and the tacrolimus dosing requirements (r(s) = -0.447, p = 0.004) and the concentration/dose ratio (r(s) = 0.351, p = 0.029). CYP3A5 expressors required median (interquartile range) higher doses of tacrolimus (0.14 [0.09] vs 0.06 [0.04] mg/kg/12 hours, p = 0.001), and had lower concentration/dose ratios (45.34 [44.54] vs 177.78 [145.38] ng/ml per mg/kg/12 hours, p < 0.0001). This relationship was not seen with the ABCB1 genotype. Age and CYP3A5 genotype predicted the tacrolimus dosing requirements as well as the concentration/dose ratio (R(2) = 0.351, p = 0.001 and R(2) = 0.521, p < 0.001). No relationship was found between any of the CYP3A5 or ABCB1 genotypes and the estimated glomerular filtration rate. Younger age and CYP3A5 expressor genotype were independently associated with higher dosing requirements and lower tacrolimus concentration/dose ratios.
MeSH Terms
- ATP Binding Cassette Transporter, Subfamily B
- ATP Binding Cassette Transporter, Subfamily B, Member 1
- Aging
- Child
- Cytochrome P-450 CYP3A
- Dose-Response Relationship, Drug
- Female
- Genotype
- Glomerular Filtration Rate
- Graft Rejection
- Heart Transplantation
- Humans
- Immunosuppressive Agents
- Kidney
- Male
- Retrospective Studies
- Severity of Illness Index
- Tacrolimus
- Time Factors
- Treatment Outcome
Variation in the ATP-binding cassette, subfamily B, member 1 transporter (ABCB1) (multidrug-resistance gene 1) gene has been investigated as a predictor of response to treatment with a variety of medications such as antiarrhythmics, chemotherapeutic agents, anti-HIV medications, and some psychotropics. The ABCB1 gene product, P-glycoprotein, affects the transport of drugs out of many cell types, including endothelial cells at the blood-brain barrier. We sought to determine if ABCB1 polymorphisms predict response to antidepressant treatment in geriatric patients. We compared the effects of ABCB1 genetic variation on the therapeutic response to paroxetine, a P-glycoprotein substrate, and to mirtazapine, which is not thought to be transported by ABCB1, in a sample of 246 elderly patients with major depression treated in a clinical trial setting. A total of 15 single nucleotide polymorphisms in the ABCB1 gene were assessed in each patient. Two of these ABCB1 single nucleotide polymorphisms were earlier reported to predict treatment response in patients prescribed with P-glycoprotein substrate antidepressants. The two earlier identified ABCB1 markers for antidepressant response predicted time to remission in our paroxetine-treated patients, but not in the mirtazapine-treated patients. These results replicate the published findings of others. If a Bonferroni correction for type I error is made, our results do not reach the criteria for statistical significance. However, the Bonferroni correction may be too conservative given the strong linkage disequilibrium among some of the markers and our aim to replicate the earlier published findings. Our study provides confirmation that certain ABCB1 polymorphisms predict response to substrate medications in geriatric patients.
MeSH Terms
- ATP Binding Cassette Transporter, Subfamily B
- ATP Binding Cassette Transporter, Subfamily B, Member 1
- Aged
- Aging
- Antidepressive Agents
- Depression
- Female
- Genotype
- Humans
- Japan
- Male
- Paroxetine
- Polymorphism, Single Nucleotide
- Survival Analysis
- Treatment Outcome
Epilepsy drug-resistance may depend on the metabolism of antiepileptic drugs (AEDs), transport to the epileptic focus and/or target sensitivity. Furthermore, drug response depends on multiple characteristics of the patient, the epilepsy, and the antiepileptic drugs used. We have investigated the association between polymorphisms related to antiepileptic drug metabolism (CYP2C9, CYP2C19, and UGT), transport (ABCB1), and targets (SCN1A) both in a crude analysis and after adjusting by clinical factors associated with drug-resistance, and stratifying by patient age or aetiology of epilepsy. Caucasian outpatients (N=289), children (N=80) and adolescent-adults (N=209), with idiopathic (N=69), cryptogenic (N=97) or symptomatic epilepsies (N=123) were selected when they had either drug-resistance (with at least four seizures over the previous year after treatment with more than three appropriate AEDs at appropriate doses) or drug responsiveness (without seizures for at least a year). Samples were genotyped by allelic discrimination using TaqMan probes. No significant association between polymorphisms and drug-resistance was found either in the crude analysis or in the adjusted analysis. However, adults with the ABCB1_3435TT or 2677TT genotypes had a lower risk of drug-resistance than those with the CC or the GG genotypes. Furthermore, patients with symptomatic epilepsies with the ABCB1_3435CT or TT genotypes had a lower risk of drug-resistance than those with the CC genotype. An opposite but insignificant tendency was found in children and in idiopathic epilepsies. Although replication studies will be needed to confirm our results, they suggest that stratification by patient age and by the aetiology of epilepsy could contribute to unmask the association between ABCB1 polymorphisms and drug-resistance of epilepsy.
MeSH Terms
- ATP Binding Cassette Transporter, Subfamily B
- ATP Binding Cassette Transporter, Subfamily B, Member 1
- Adolescent
- Adult
- Aging
- Anticonvulsants
- Aryl Hydrocarbon Hydroxylases
- Child
- Child, Preschool
- Cytochrome P-450 CYP2C19
- Cytochrome P-450 CYP2C9
- Drug Resistance
- Epilepsy
- Female
- Gene Frequency
- Genetic Predisposition to Disease
- Genotype
- Glucuronosyltransferase
- Humans
- Male
- Middle Aged
- NAV1.1 Voltage-Gated Sodium Channel
- Nerve Tissue Proteins
- Odds Ratio
- Polymorphism, Single Nucleotide
- Sodium Channels
- Young Adult
The T cell branch of the immune system has been extensively studied in the elderly and it is known that the elderly have impaired immune function, mainly due to the chronic antigenic load that ultimately causes shrinkage of the T cell repertoire and filling of the immunologic space with memory T cells. In the present paper, we describe the IgD(-)CD27(-) double-negative B cell population which (as we have recently described) is higher in the elderly. Most of these cells were IgG( ). Evaluation of the telomere length and expression of the ABCB1 transporter and anti-apoptotic molecule, Bcl2, shows that they have the markers of memory B cells. We also show that these cells do not act as antigen presenting cells, as indicated by the low levels of CD80 and DR, nor do they express significant levels of the CD40 molecule necessary to interact with T lymphocytes through the ligand, CD154. Hence, we hypothesize that these expanded cells are late memory or exhausted cells that have down-modulated the expression of CD27 and filled the immunologic space in the elderly. These cells might be the age-related manifestation of time-enduring stimulation or dysregulation of the immune system.
MeSH Terms
- ATP Binding Cassette Transporter, Subfamily B
- ATP Binding Cassette Transporter, Subfamily B, Member 1
- Adult
- Age Factors
- Aged
- Aged, 80 and over
- Aging
- Antigens, CD19
- B-Lymphocyte Subsets
- B7-1 Antigen
- CD40 Antigens
- Cells, Cultured
- Flow Cytometry
- HLA-DR Antigens
- Humans
- Immunoglobulin D
- Immunologic Memory
- Ki-67 Antigen
- Middle Aged
- Proto-Oncogene Proteins c-bcl-2
- Telomere
- Tumor Necrosis Factor Receptor Superfamily, Member 7
- Young Adult
Evaluation of: Fanta S, Niemi M, Jönsson S et al.: Pharmacogenetics of cyclosporine in children suggests an age-dependent influence of ABCB1polymorphisms. Pharmacogenet. Genomics 18(2), 77-90 (2008). The clinical use of the immunosuppressive agent cyclosporine is complicated by its toxicity, narrow therapeutic window and highly variable pharmacokinetics between individuals. In adults, genetic polymorphisms in the genes encoding the cyclosporine-metabolizing enzymes CYP3A4 and CYP3A5, as well as the ABCB1 gene, which encodes the efflux-pump P-glycoprotein, seem to have a limited effect, if any, on cyclosporine pharmacokinetics. However, the authors have now reported for the first time an association between cyclosporine oral bioavailability and the ABCB1 c.1236C>T and c.2677G>T polymorphisms, as well as the related haplotype c.1199G-c.1236C-c.2677G-c.3435C, in children with end-stage renal disease older than 8 years of age. Carriers of the variant alleles had a cyclosporine oral bioavailability that was around 1.5-times higher compared with noncarriers. This association was not observed in children younger than 8 years of age. In addition, no relation between cyclosporine disposition and genetic variation in the CYP3A4, CYP3A5, ABCC2, SLCO1B1 and NR1I2 genes was observed. These data suggest that the effect of ABCB1 polymorphisms on cyclosporine pharmacokinetics is related to age, and thus developmental stage. Although further study is necessary to establish the predictive value of ABCB1 genotyping for individualization of cyclosporine therapy in children older than 8 years, an important step towards further personalized immunosuppressive drug therapy has been made.
MeSH Terms
- ATP Binding Cassette Transporter, Subfamily B
- ATP Binding Cassette Transporter, Subfamily B, Member 1
- Adult
- Aging
- Child
- Cyclosporine
- Humans
- Immunosuppressive Agents
- Inactivation, Metabolic
- Kidney Transplantation
- Pharmacogenetics
- Polymorphism, Single Nucleotide
Aging modifies a number of functional and phenotypic parameters of cells from the immune system. In this study, the activities of two members of the superfamily of ATP-binding cassette (ABC) transport proteins, ABCB1 and ABCC (measured by rhodamine 123 efflux and Fluo-3 efflux respectively), were compared in murine bone marrow cells and thymocytes of young (3-4 weeks old), adult (2-3 months old) and old (18 months old) mice. ABCB1 activity was shown to be age regulated in murine bone marrow mononuclear cells and thymocytes. In the bone marrow, the increased amount of cells with ABCB1 activity observed in old mice was restricted to the c-kit(-)Sca-1( ) and c-kit( )Sca-1( ) subpopulations. Only a small percentage of c-kit( ) cells in the thymus had ABCB1 activity, and this subpopulation increased with age. In the thymus, old age augmented this activity in the CD4(-) CD8(-) double-negative cells and in the CD4( ) and CD8( ) single-positive populations. The activity of another ABC transporter, the ABCC-related activity, was also modified by age in the bone marrow. However, the age-related increase was observed in the subpopulations were ABCB1 was not modified, namely the non-progenitor population (c-kit(-)Sca-1(-)cells) and c-kit( )Sca-1(-) cells. Nearly, all thymocytes expressed the ABCC1 molecule in an active form and aging did not affect this pattern. This study demonstrates an independent upregulation of ABCB1 and ABCC activities during the aging process. The increases were observed in different subsets of cells but followed a developmentally regulated pattern. The functions played by these transporters and alterations in aging are discussed.
MeSH Terms
- ATP Binding Cassette Transporter, Subfamily B
- ATP Binding Cassette Transporter, Subfamily B, Member 1
- ATP-Binding Cassette Transporters
- Aging
- Animals
- Bone Marrow Cells
- Cells, Cultured
- Hematopoietic Stem Cells
- Leukocytes, Mononuclear
- Male
- Mice
- Mice, Inbred C57BL
- Multidrug Resistance-Associated Proteins
- Thymus Gland
Risperidone (R) is metabolized to 9-hydroxyrisperidone (9-OHR) by cytochrome P450 2D6 (CYP2D6). The main objective of this naturalistic study was to investigate the variables associated with two plasma ratios: the plasma R:9-OHR concentration ratio and the total concentration-to-dose (C:D) ratio. These ratios were studied as continuous measures by linear regression analyses and as three dichotomous variables in logistic regression analyses: R:9-OHR ratio >1 (indicative of lack of CYP2D6 activity), C:D ratio >14 (indicative of diminished R elimination), and C:D ratio <3.5 (indicative of increased R elimination). Plasma R levels; genotypes for CYP2D6, CYP3A5; and ABCB1 genes, and co-medication, including CYP inhibitors and CYP3A inducers, were studied in 277 patients. Almost all CYP2D6 poor metabolizers (PMs) had an inverted R:9-OHR ratio (>1). Having a CYP2D6 PM phenotype was strongly associated with a C:D ratio >14 (OR=8.2; 95% confidence interval [CI]=2.0-32.7), indicating diminished R elimination. CYP2D6 ultrarapid metabolizers (UMs) did not exhibit an increased R elimination. Some ABCB1 (or MDR1) variants were significantly associated with increased R:9-OHR ratios and decreased C:D ratios, but the results were neither consistent nor robust. Taking CYP inhibitors was significantly associated with a C:D ratio >14 (OR=3.8; CI=1.7-8.7) and with an inverted R:9-OHR ratio. Taking CYP3A inducers was significantly associated with a C:D ratio <3.5 (OR=41.8; CI=12.7-138), indicating increased R elimination. Female gender and old age appeared to be associated with a lower R elimination. Our study indicated that the CYP2D6 PM phenotype may have a major role in personalizing R doses, whereas the CYP3A5 PM phenotype probably has no role. CYP inducers and inhibitors appear to be relevant to R dosing. New studies are needed, particularly to further assess the role of the CYP2D6 UM phenotype and ABCB1 variants in R pharmacokinetics.
MeSH Terms
- ATP Binding Cassette Transporter, Subfamily B
- ATP Binding Cassette Transporter, Subfamily B, Member 1
- Adult
- Aging
- Antipsychotic Agents
- Cytochrome P-450 CYP2D6
- Cytochrome P-450 CYP2D6 Inhibitors
- Cytochrome P-450 CYP3A
- Cytochrome P-450 Enzyme Inhibitors
- Cytochrome P-450 Enzyme System
- Drug Interactions
- Enzyme Induction
- Female
- Humans
- Isoxazoles
- Linear Models
- Male
- Middle Aged
- Organic Anion Transporters
- Paliperidone Palmitate
- Pyrimidines
- Risperidone
- Sex Factors
The family of adenosine triphosphate (ATP)-binding cassette (ABC) transporters is the largest gene family known. While some ABC transporters translocate single substances across membranes with high specificity, others transport a wide variety of different lipophilic compounds. They are responsible for many physiological processes and are also implicated in a number of diseases. The present review focuses on ABC transporter genes which are involved in ageing and age-related diseases. Expression of ABCB1 (MDR1, P-glycoprotein) increases with age in CD4( ) and CD8( ) T-lymphocytes indicating that P-glycoprotein may be involved in the secretion of cytokines, growth factors, and cytotoxic molecules. As T cells in aged individuals are hyporesponsive leading to a reduced immunodefence capability, a role of ABCB1 in age-related immunological processes is presumed. The ABCA1 (ABC1) gene product translocates intracellular cholesterol and phospholipids out of macrophages. Genetic aberrations in ABCA1 cause perturbations in lipoprotein metabolism and contribute to atherosclerosis. ABCA4 (ABCR) represents a retina-specific ABC transporter expressed in rod photoreceptor cells. The ABCA4 gene product translocates retinyl-derivatives. Mutations in the ABCA4 gene contribute to age-related macular degeneration. Polymorphisms in the sulfonylurea receptor gene (ABCC8, SUR1) are associated with non-insulin-dependent diabetes mellitus (NIDDM). Sulfonylureas inhibit potassium conductance and are used to treat NIDDM by stimulation of insulin secretion across ATP-sensitive potassium channels in pancreatic beta-cell membranes. Possible diagnostic and therapeutic implications of ABC transporters for age-related diseases are discussed.
MeSH Terms
- ATP-Binding Cassette Transporters
- Aging
- Animals
- Arteriosclerosis
- Diabetes Mellitus, Type 2
- Gene Expression Regulation
- Humans
- Macular Degeneration