[Show abstract][Hide abstract] ABSTRACT: Cholesterol-lowering therapy has been related with several pleiotropic effects including anti-inflammatory action in vascular endothelium; however their influence on monocyte adhesion molecules is poorly described.
To investigate the effect of inhibitors of synthesis (statins) and absorption (ezetimibe) of cholesterol on expression of adhesion molecules L-selectin, PSGL-1, VLA-4, LFA-1 and Mac-1 in mononuclear cells in vivo and in vitro using THP-1.
The influence of simvastatin (10 mg/day), ezetimibe (10 mg/day) and their combination (10 mg each/day) on mRNA expression of adhesion molecules was analyzed in peripheral blood mononuclear cells (PBMC) from hypercholesterolemics. The effects of atorvastatin, simvastatin and ezetimibe on mRNA and protein expression of adhesion molecules were also evaluated in THP-1 cells.
Simvastatin/ezetimibe combination, but not the monotherapies, reduced the mRNA expression of the PSGL-1, LFA-1 and Mac-1 genes in PBMC from hypercholesterolemics. Total and LDL cholesterol in serum correlated with PSGL-1 mRNA expression, whereas HDL cholesterol negatively correlated with mRNA levels of L-selectin and VLA-4 genes (p<0.05). Plasma hsCRP was also correlated with mRNA levels of VLA-4, LFA-1 and Mac-1 (p<0.05). Atorvastatin and simvastatin at 10 μM reduced mRNA and protein expression of L-Selectin, PSGL-1 and VLA-4 in THP-1 cells (p<0.05).
Cholesterol-lowering therapy modulates gene expression of adhesion molecules in PBMC from hypercholesterolemics and THP-1 cells. Simvastatin/ezetimibe combination gives more benefits by reducing to a larger extent the expression of adhesion molecules in mononuclear cells. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: The aim of the study was to investigate whether adiposity and metabolic markers, such as leptin, glucose, and lipids, are influenced by leptin (LEP) and leptin receptor (LEPR) gene polymorphisms in a sample of our population.
A group of 326 individuals of Caucasian-European descent, aged 30 to 80 years, 87 men and 239 women, 148 obese and 178 non-obese, was randomly selected at two clinical hospitals in the city of Sao Paulo, Brazil. All individuals declared their ethnic group as white during the initial interview. Anthropometric measurements, body mass index (BMI), and fat mass were evaluated. Blood samples were drawn for DNA extraction and measurements of leptin, soluble leptin receptor, glucose, and lipids. LEP -2548G>A and LEPR Lys109Arg (c.326A>G), Gln233Arg (c.668A>G) and Lys656Asn (c.1968G>C) polymorphisms were detected by PCR-RFLP.
Increased leptin and serum lipids, and LEPR Arg223Arg (GG genotype) were associated with higher risk for obesity (p < 0.05), while reduced risk was found in LEPR Arg109Arg (GG genotype) carriers (OR: 0.38, 95%CI: 0.19-0.77, p = 0.007). Multiple linear regression analysis showed a relationship between LEPR 223Arg, increased waist circumference, and leptinemia (p < 0.05), while LEPR 109Arg was associated with high total cholesterol and triglycerides (p < 0.05). LEPR haplotype 3 (AGG: 109Lys/233Arg/656Lys) carriers have increased risk for obesity (OR: 2.56, 95% CI: 1.19-5.49, p = 0.017). Moreover, this haplotype was associated with increased BMI, waist circumference, and leptinemia (p < 0.05).
LEPR polymorphisms are associated with obesity, hyperleptinemia, and atherogenic lipid profile, suggesting their potential role for leptin resistance and cardiovascular risk. Moreover, LEPR haplotype 3 confers susceptibility to adiposity and hyperleptinemia in our population.
Full-text · Article · Dec 2013 · Arquivos brasileiros de endocrinologia e metabologia
[Show abstract][Hide abstract] ABSTRACT: Reverse cholesterol transport (RCT) has been inversely related to atherosclerosis and cardiovascular risk. The influence of menopause in the RCT process is poorly understood and the effects of cholesterol-lowering interventions, including statins and hormone therapy (HT), on genes controlling the RCT in postmenopausal women are also unknown.
The effects on serum lipids and expression profile of genes involved in RCT -APOA1, ABCA1, ABCG1, SCARB1 and LXRA- were evaluated by TaqMan(®) quantitative PCRin peripheral blood mononuclear cells (PBMC) from 87 postmenopausal hypercholesterolemic women treated with atorvastatin (AT, n=17), estrogen or estrogen plus progestagen (HT, n=34) and estrogen or estrogen plus progestagen associated with atorvastatin (HT+AT, n=36).
Atorvastatin and HT treatments reduced the mRNA levels of APOA1 and SCARB1, respectively, whereas ABCA1 expression was reduced after all treatments. Although the expression of LXRA, an important transcription factor controlling the expression of genes involved in RCT, was not modified after any treatment, it was correlated with ABCA1, APOA1 and SCARB1 RNAm values before and after treatments, however no correlation with ABCG1 was observed. In a linear regression analysis, HT was related to an increase in apoAI levels after treatment when compared to atorvastatin and, moreover, higher SCARB1 and ABCA1 basal expression were also associated with decreased apoAI levels after treatments.
ABCA1 mRNA levels are decreased by atorvastatin and HT, however these treatments have a differential effect on APOA1 and SCARB1 expression in PBMC from postmenopausal women. Basal ABCA1 and SCARB1 expression profile could be helpful markers in predicting the effect of atorvastatin and HT on RCT, according to the changes in apoAI levels in this sample population.
Full-text · Article · Sep 2013 · The Journal of steroid biochemistry and molecular biology
[Show abstract][Hide abstract] ABSTRACT: Background:
Variability of response to statins has been related to polymorphisms in genes involved in cholesterol homeostasis and statin metabolism, such as CYP3A4 and CYP3A5. We investigated the effects of atorvastatin on CYP3A4 and CYP3A5 mRNA expression in mononuclear cells and on CYP3A activity and their interactions with common variants.
Unrelated individuals (n=121) with hypercholesterolemia (HC) were treated with atorvastatin (10 mg/day/4 weeks). Ninety-two normolipidemic (NL) subjects were selected as a control group. Genotype analysis of CYP3A4*1B (rs2740574), CYP3A4*22 (rs35599367), CYP3A5*3C (rs776746), and CYP3A5*1D (rs15524) and mRNA levels in peripheral blood mononuclear cells (PBMCs) were estimated. CYP3A activity was phenotyped by the urinary cortisol to 6-beta-hydroxy-cortisol ratio.
LDL cholesterol reduction in response to atorvastatin was positively correlated with change in CYP3A4 (R(2)=0.039, p=0.037) and CYP3A5 (R(2)=0.047, p=0.019) mRNA levels and negatively correlated with CYP3A activity (R(2)=0.071, p=0.022). CYP3A5*3C (AGT haplotype) was associated to lower basal CYP3A5 mRNA expression in HC (p<0.045), however none of the haplotype groups impacted treatment.
It is likely that cholesterolemia status changes promoted by atorvastatin play a role in regulating CYP3A4 and CYP3A5 mRNA expression in PBMCs, as well as CYP3A activity. CYP3A5*3C (AGT haplotype) also contributes for the variability of CYP3A5 mRNA levels in PBMCs.
Full-text · Article · Mar 2013 · Clinica chimica acta; international journal of clinical chemistry
[Show abstract][Hide abstract] ABSTRACT: Objective:
Using candidate gene approach, we have investigated the effect of single nucleotide polymorphism (SNP) in genes related to lipid metabolism and atherosclerosis on dyslipidemia and atorvastatin response.
The study included 157 patients treated with atorvastatin and 145 controls. Genomic DNA was isolated and genotyped using SNPlex technology.
Allele and genotype disease association test revealed that APOB rs693 (OR: 2.2 [1.5-3.2], p=0.0001) and CD36 rs1984112 (OR: 3.7 [1.9-7.0], p=0.0002) SNPs were independent risk factors for hypercholesterolemia. Only APOB rs693 T variant allele was associated with increased LDL cholesterol levels (>160mg/dL). After atorvastatin treatment (10mg/day/4weeks), LIPC -514T allele was positively associated with LDL cholesterol reduction.
The current study reinforces the current knowledge that carrying APOB rs693 is an independent risk factor for dyslipidemia and higher LDL levels. Furthermore, we found that a variant of CD36 was associated with dyslipidemia as a risk (rs1984112) factor. Finally, atorvastatin response could be predicted by LIPC -514C>T SNP and physical activity. In conclusion, our data evidences the contribution of genetic markers and their interaction with environmental factor in the variability of statin response.
Full-text · Article · Dec 2012 · Clinica chimica acta; international journal of clinical chemistry
[Show abstract][Hide abstract] ABSTRACT: Balancing the subject composition of case and control groups to create homogenous ancestries between each group is essential for medical association studies.
We explored the applicability of single-tube 34-plex ancestry informative markers (AIM) single nucleotide polymorphisms (SNPs) to estimate the African Component of Ancestry (ACA) to design a future case-control association study of a Brazilian urban sample.
One hundred eighty individuals (107 case group; 73 control group) self-described as white, brown-intermediate or black were selected. The proportions of the relative contribution of a variable number of ancestral population components were similar between case and control groups. Moreover, the case and control groups demonstrated similar distributions for ACA <0.25 and >0.50 categories. Notably a high number of outlier values (23 samples) were observed among individuals with ACA <0.25. These individuals presented a high probability of Native American and East Asian ancestral components; however, no individuals originally giving these self-described ancestries were observed in this study.
The strategy proposed for the assessment of ancestry and adjustment of case and control groups for an association study is an important step for the proper construction of the study, particularly when subjects are taken from a complex urban population. This can be achieved using a straight forward multiplexed AIM-SNPs assay of highly discriminatory ancestry markers.
Full-text · Article · Jan 2012 · Genetic Testing and Molecular Biomarkers
[Show abstract][Hide abstract] ABSTRACT: The relationship between variants in SLCO1B1 and SLCO2B1 genes and lipid-lowering response to atorvastatin was investigated.
One-hundred-thirty-six unrelated individuals with hypercholesterolemia were selected and treated with atorvastatin (10 mg/day/4 weeks). They were genotyped with a panel of ancestry informative markers for individual African component of ancestry (ACA) estimation by SNaPshot(®) and SLCO1B1 (c.388A>G, c.463C>A and c.521T>C) and SLCO2B1 (-71T>C) gene polymorphisms were identified by TaqMan(®) Real-time PCR.
Subjects carrying SLCO1B1 c.388GG genotype exhibited significantly high low-density lipoprotein (LDL) cholesterol reduction relative to c.388AA+c.388AG carriers (41 vs. 37%, p = 0.034). Haplotype analysis revealed that homozygous of SLCO1B1*15 (c.521C and c.388G) variant had similar response to statin relative to heterozygous and non-carriers. A multivariate logistic regression analysis confirmed that c.388GG genotype was associated with higher LDL cholesterol reduction in the study population (OR: 3.2, CI95%:1.3-8.0, p < 0.05).
SLCO1B1 c.388A>G polymorphism causes significant increase in atorvastatin response and may be an important marker for predicting efficacy of lipid-lowering therapy.
Full-text · Article · Dec 2011 · International Journal of Molecular Sciences
[Show abstract][Hide abstract] ABSTRACT: Apolipoprotein E (apoE) is a key component of the lipid metabolism. Polymorphisms at the apoE gene (APOE) have been associated with cardiovascular disease, lipid levels and lipid-lowering response to statins. We evaluated the effects on APOE expression of hypercholesterolemia, APOE ε2/ε3/ε4 genotypes and atorvastatin treatment in Brazilian individuals. The relationship of APOE genotypes and plasma lipids and atorvastatin response was also tested in this population.
APOE ε2/ε3/ε4 and plasma lipids were evaluated in 181 normolipidemic (NL) and 181 hypercholesterolemic (HC) subjects. HC individuals with indication for lowering-cholesterol treatment (n = 141) were treated with atorvastatin (10 mg/day/4-weeks). APOE genotypes and APOE mRNA in peripheral blood mononuclear cells (PBMC) were analyzed by TaqMan real time PCR.
HC had lower APOE expression than NL group (p < 0.05) and individuals with low APOE expression showed higher plasma total and LDL cholesterol and apoB, as well as higher apoAI (p < 0.05). Individuals carrying ε2 allele have reduced risk for hypercholesterolemia (OR: 0.27, 95% I.C.: 0.08-0.85, p < 0.05) and NL ε2 carriers had lower total and LDL cholesterol and apoB levels, and higher HDL cholesterol than non-carriers (p < 0.05). APOE genotypes did not affect APOE expression and atorvastatin response. Atorvastatin treatment do not modify APOE expression, however those individuals without LDL cholesterol goal achievement after atorvastatin treatment according to the IV Brazilian Guidelines for Dyslipidemia and Atherosclerosis Prevention had lower APOE expression than patients with desirable response after the treatment (p < 0.05).
APOE expression in PBMC is modulated by hypercholesterolemia and the APOE mRNA level regulates the plasma lipid profile. Moreover the expression profile is not modulated neither by atorvastatin nor APOE genotypes. In our population, APOE ε2 allele confers protection against hypercholesterolemia and a less atherogenic lipid profile. Moreover, low APOE expression after treatment of patients with poor response suggests a possible role of APOE level in atorvastatin response.
Full-text · Article · Nov 2011 · Lipids in Health and Disease
[Show abstract][Hide abstract] ABSTRACT: Menopause is associated with changes in lipid levels resulting in increased risk of atherosclerosis and cardiovascular events. Hormone therapy (HT) and atorvastatin have been used to improve lipid profile in postmenopausal women. Effects of HT, atorvastatin and APOE polymorphisms on serum lipids and APOE and LXRA expression were evaluated in 87 hypercholesterolemic postmenopausal women, randomly selected for treatment with atorvastatin (AT, n=17), estrogen or estrogen plus progestagen (HT, n=34) and estrogen or estrogen plus progestagen associated with atorvastatin (HT+AT, n=36). RNA was extracted from peripheral blood mononuclear cells (PBMC) and mRNA expression was measured by TaqMan(®) PCR. APOE ɛ2/ɛ3/ɛ4 genotyping was performed using PCR-RFLP. Total cholesterol (TC), LDL-c and apoB were reduced after each treatment (p<0.001). Triglycerides, VLDL-c and apoAI were reduced only after atorvastatin (p<0.05), whereas triglycerides and VLDL-c were increased after HT (p=0.01). HT women had lower reduction on TC, LDL-c and apoB than AT and HT+AT groups (p<0.05). APOE mRNA expression was reduced after atorvastatin treatment (p=0.03). Although LXRA gene expression was not modified by atorvastatin, it was correlated with APOE mRNA before and after treatments. Basal APOE mRNA expression was not influenced by gene polymorphisms, however the reduction on APOE expression was more pronounced in ɛ3ɛ3 than in ɛ3ɛ4 carriers. Atorvastatin down-regulates APOE mRNA expression and it is modified by APOE genotypes in PBMC from postmenopausal women.
Full-text · Article · Nov 2011 · The Journal of steroid biochemistry and molecular biology
[Show abstract][Hide abstract] ABSTRACT: This study evaluated the influence of polymorphisms and cholesterol-lowering treatments on SCARB1 mRNA expression in peripheral blood mononuclear cells and in HepG2 and Caco-2 cells.
Blood samples were drawn from normolipidemic (NL, n = 166) and hypercholesterolemic (HC, n = 123) individuals to extract DNA and total RNA and to analyze the lipid profile. After a 4-week washout period, 98 HC individuals were treated with atorvastatin (10 mg/day/4 weeks) whereas 25 were treated with ezetimibe (10 mg/day/4 weeks), followed by simvastatin (10 mg/day/8 weeks) and simvastatin plus ezetimibe (10 mg each/day/4 weeks). HepG2 and Caco-2 cells were treated with atorvastatin, simvastatin and ezetimibe at various concentrations for 12 and 24 h and collected for RNA extraction. SCARB1 mRNA expression was measured by TaqMan® assay and SCARB1 c.4G> A, c.726 + 54C> T and c.1080C> T polymorphisms were detected by PCR-RFLP.
High LDL cholesterol (> 160 mg/dL) values were associated with low baseline SCARB1 mRNA expression in PBMC. Allele T carriers for SCARB1 c.726+54C> T had lower basal SCARB1 transcription in PBMC (p < 0.05). Simvastatin, atorvastatin and ezetimibe treatments did not modify the SCARB1 mRNA level in PBMC from HC patients. Similarly, these cholesterol-lowering drugs did not modulate the SCARB1 expression in HepG2 and Caco-2 cells in spite of the concentration and time of exposure (p > 0.05).
LDL cholesterol levels and SCARB1 c.726 + 54C> T are associated with low mRNA expression in mononuclear cells. Cholesterol-lowering drugs do not modulate SCARB1 expression in PBMC from HC subjects or in HepG2 and Caco-2 cells.
Full-text · Article · Apr 2011 · Journal of atherosclerosis and thrombosis
[Show abstract][Hide abstract] ABSTRACT: Enterocytes play a crucial role in high-density lipoprotein (HDL) biogenesis. Statins and ezetimibe are potent lowering-cholesterol drugs, which can also influence HDL plasma concentrations. We hypothesized that these drugs could modulate the expression of intestinal ABCA1 and ABCG1, two genes involved in HDL metabolism.
Caco-2 cells were used as a model of the human intestinal cells and were treated with statins (0.01-1 μmol/L) and/or ezetimibe (0.5-5.0 μmol/L) for 12 h or 24 h. Gene expression was examined using real-time PCR.
ABCA1 level was more abundant than ABCG1 in Caco-2 cells. ABCA1 was downregulated after 12-h and 24-h treatment with atorvastatin (0.1 and 1.0 μmol/L) or simvastatin (0.01, 0.1 and 1 μmol/L) (p<0.05). In statin-treated cells, ABCG1 levels remained unaltered. Ezetimibe alone did not induce change of ABCA1 or ABCG1 mRNA levels (p>0.05) but 24-h ezetimibe (2.5 or 5.0 μmol/L) plus simvastatin (1 μmol/L) treatment decreased the transcription of ABCA1 and ABCG1 (p<0.05).
Our findings reveal that, at the concentrations studied, statins isolated or combined with ezetimibe, but not ezetimibe alone, downregulate ABCA1 mRNA expression in Caco-2 cells. Moreover, simvastatin combined with ezetimibe treatment also decrease the ABCG1 levels in these cells.
Full-text · Article · Mar 2011 · Drug metabolism and drug interactions
[Show abstract][Hide abstract] ABSTRACT: The ATP-binding cassette transporters, ABCA1 and ABCG1, are LXR-target genes that play an important role in reverse cholesterol transport. We examined the effects of inhibitors of the cholesterol absorption (ezetimibe) and synthesis (statins) on expression of these transporters in HepG2 cells and peripheral blood mononuclear cells (PBMCs) of individuals with primary (and nonfamilial) hypercholesterolemia (HC).
A total of 48 HC individuals were treated with atorvastatin (10 mg/day/4 weeks) and 23 were treated with ezetimibe (10 mg/day/4 weeks), followed by simvastatin (10 mg/day/8 weeks) and simvastatin plus ezetimibe (10 mg of each/day/4 weeks). Gene expression was examined in statin- or ezetimibe-treated and control HepG2 cells as well as PBMCs using real-time PCR. Results: In PBMCs, statins and ezetimibe downregulated ABCA1 and ABCG1 mRNA expression but did not modulate NR1H2 (LXR-β) and NR1H3 (LXR-α) levels. Positive correlations of ABCA1 with ABCG1 and of NR1H2 with NR1H3 expressions were found in all phases of the treatments. In HepG2 cells, ABCA1 mRNA levels remained unaltered while ABCG1 expression was increased by statin (1.0-10.0 µM) or ezetimibe (5.0 µM) treatments. Atorvastatin upregulated NR1H2 and NR1H3 only at 10.0 µM, meanwhile ezetimibe (1.0-5.0 µM) downregulated NR1H2 but did not change NR1H3 expression.
Our findings reveal that lipid-lowering drugs downregulate ABCA1 and ABCG1 mRNA expression in PBMCs of HC individuals and exhibit differential effects on HepG2 cells. Moreover, they indicate that the ABCA1 and ABCG1 transcript levels were not correlated directly to LXR mRNA expression in both cell models treated with lipid-lowering drugs.
[Show abstract][Hide abstract] ABSTRACT: The SR-BI is a key component on the cholesterol metabolism. Polymorphisms in the SR-BI gene (SCARB1) were related with variations on plasma lipoprotein profile and other risk factors for cardiovascular disease. We tested the relationship of 3 SCARB1 single nucleotide polymorphisms (SNPs) with hypercholesterolemia in a Brazilian population and whether these variants can influence lipid-lowering response to atorvastatin.
c.4G>A, c.726+54C>T and c.1050C>T SNPs and serum concentrations of lipid and apolipoproteins were evaluated in 147 hypercholesterolemic (HC) and 185 normolipidemic (NL) unrelated Brazilian subjects. HC patients were treated with atorvastatin (10 mg/day/4 weeks).
Frequencies of SCARB1 polymorphisms were similar between the HC and NL groups (p>0.05). The T allele for c.726+54C>T was associated with higher LDL-c in NL and with higher apoB and apoB/apoAI in HC (p<0.05). HC individuals carrying c.1050C allele carriers (CC and CT genotypes) had lower change of total cholesterol, LDL-c, apoB and apoB/apoAI ratio (p<0.05) than the TT genotype carriers in response to atorvastatin.
The SCARB1 polymorphisms are related with variations in serum lipids in the Brazilian population and c.1050C>T SNP is associated with lipid-lowering atorvastatin response.
No preview · Article · May 2010 · Clinica chimica acta; international journal of clinical chemistry
[Show abstract][Hide abstract] ABSTRACT: The ATP-binding cassette transporter A1 (ABCA1) has an essential role in the formation of nascent high-density lipoprotein particles and also participates in the cholesterol efflux from macrophages in the artery wall. Several substances, such as statins, or even gene variants are able to modulate ABCA1 expression. There is strong evidence that statin treatment downregulates the ABCA1 expression in nonloaded macrophages. Interestingly, in cholesterol-loaded macrophages, which are more relevant to atherogenesis, this effect is lost. We observed an inhibitory effect of atorvastatin in peripheral blood mononuclear cells of hypercholesterolemic individuals. Moreover, in these individuals, the ABCA1 -14C>T polymorphism was associated with high baseline gene-expression levels. Other studies are needed to evaluate how relevant these findings are to the formation of arterial foam cells in vivo.
No preview · Article · Jul 2009 · Pharmacogenomics
[Show abstract][Hide abstract] ABSTRACT: Statin disposition and response are greatly determined by the activities of drug metabolizing enzymes and efflux/ uptake transporters. There is little information on the regulation of these proteins in human cells after statin therapy. In this study, the effects of atorvastatin and simvastatin on mRNA expression of efflux (ABCB1, ABCG2 and ABCC2) and uptake (SLCO1B1, SLCO2B1 and SLC22A1) drug transporters in Caco-2 and HepG2 cells were investigated.
Quantitative real-time PCR was used to measure mRNA levels after exposure of HepG2 and Caco-2 cells to statins.
Differences in mRNA basal levels of the transporters were as follows: ABCC2>ABCG2>ABCB1>SLCO1B1>SLC22A1>SLC O2B1 for HepG2 cells, and SLCO2B1>ABCC2>ABCB1>ABCG2>SLC22A1 for Caco-2 cells. While for HepG2 cells, ABCC2, ABCG2 and SLCO2B1 mRNA levels were significantly up-regulated at 1, 10 and 20 micromol/L after 12 or 24 h treatment, in Caco-2 cells, only the efflux transporter ABCB1 was significantly down-regulated by two-fold following a 12 h treatment with atorvastatin. Interestingly, whereas treatment with simvastatin had no effect on mRNA levels of the transporters in HepG2 cells, in Caco-2 cells the statin significantly down-regulated ABCB1, ABCC2, SLC22A1, and SLCO2B1 mRNA levels after 12 or 24 h treatment.
These findings reveal that statins exhibits differential effects on mRNA expression of drug transporters, and this effect depends on the cell type. Furthermore, alterations in the expression levels of drug transporters in the liver and/or intestine may contribute to the variability in oral disposition of statins.Acta Pharmacologica Sinica (2009) 30: 956-964; doi: 10.1038/aps.2009.85; published online 22 June 2009.
Full-text · Article · Jun 2009 · Acta Pharmacologica Sinica
[Show abstract][Hide abstract] ABSTRACT: This study investigated the effects of atorvastatin on ABCB1 and ABCC1 mRNA expression on peripheral blood mononuclear cells (PBMC) and their relationship with gene polymorphisms and lowering-cholesterol response. One hundred and thirty-six individuals with hypercholesterolemia were selected and treated with atorvastatin (10 mg/day/4 weeks). Blood samples were collected for serum lipids and apolipoproteins measurements and DNA and RNA extraction. ABCB1 (C3435T and G2677T/A) and ABCC1 (G2012T) gene polymorphisms were identified by polymerase chain reaction-restriction (PCR)-RFLP and mRNA expression was measured in peripheral blood mononuclear cells by singleplex real-time PCR. ABCB1 polymorphisms were associated with risk for coronary artery disease (CAD) (p<0.05). After atorvastatin treatment, both ABCB1 and ABCC1 genes showed 50% reduction of the mRNA expression (p<0.05). Reduction of ABCB1 expression was associated with ABCB1 G2677T/A polymorphism (p=0.039). Basal ABCB1 mRNA in the lower quartile (<0.024) was associated with lower reduction rate of serum low-density lipoprotein (LDL) cholesterol (33.4+/-12.4%) and apolipoprotein B (apoB) (17.0+/-31.3%) when compared with the higher quartile (>0.085: LDL-c=40.3+/-14.3%; apoB=32.5+/-10.7%; p<0.05). ABCB1 substrates or inhibitors did not affect the baseline expression, while ABCB1 inhibitors reversed the effects of atorvastatin on both ABCB1 and ABCC1 transporters. In conclusion, ABCB1 and ABCC1 mRNA levels in PBMC are modulated by atorvastatin and ABCB1 G2677T/A polymorphism and ABCB1 baseline expression is related to differences in serum LDL cholesterol and apoB in response to atorvastatin.