RESUMO
BACKGROUND: The proprotein convertase subtilisin/kexin type 9 (PCSK9) has a key role in the regulation of plasma low-density lipoprotein (LDL) cholesterol by enhancing the degradation of LDL receptor. Functional variants in PCSK9 have been associated with differences in plasma lipids and may contribute to the variability of the response to cholesterol-lowering drugs. OBJECTIVE: To investigate the influence of PCSK9 variants on plasma lipid profile and response to atorvastatin in Brazilian subjects. METHODS: PCSK9 E670G, I474V, and R46L single nucleotide polymorphisms (SNPs) and plasma lipids were evaluated in 163 hypercholesterolemics (HC) and 171 normolipidemics (NL). HC patients with indication for cholesterol-lowering drug therapy (n = 128) were treated with atorvastatin (10 mg/d/4 wk). PCSK9 SNPs were analyzed by real time polymerase chain reaction. RESULTS: Frequencies of the PCSK9 SNPs were similar between the HC and NL groups. Logistic regression analysis showed a trend of association between PCSK9 E670G and hypercholesterolemia after adjustment for covariates (P = .059). The 670G allele was associated with high basal levels of LDL cholesterol (P = .03) in HC patients using the extreme discordant phenotype method. No association tests were performed for R46L variant because of its very low frequency, whereas the I474V polymorphism and PCSK9 haplotypes were not related to hypercholesterolemia or variability on plasma lipids in both NL and HC groups (P > .05). LDL cholesterol reduction in response to atorvastatin was not influenced by PCSK9 genotypes or haplotypes. CONCLUSIONS: PCSK9 E670G polymorphism but not I474V contributes to the variability on plasma LDL cholesterol levels in hypercholesterolemic subjects. Both PCSK9 variants have no influence on cholesterol-lowering response to atorvastatin.
Assuntos
Biomarcadores Farmacológicos/metabolismo , LDL-Colesterol/metabolismo , Hipercolesterolemia/genética , Mutação/genética , Pró-Proteína Convertases/genética , Serina Endopeptidases/genética , Adulto , Idoso , Atorvastatina , Brasil , Feminino , Ácidos Heptanoicos/administração & dosagem , Humanos , Hipercolesterolemia/tratamento farmacológico , Hipercolesterolemia/metabolismo , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Pró-Proteína Convertase 9 , Pró-Proteína Convertases/metabolismo , Pirróis/administração & dosagem , Serina Endopeptidases/metabolismo , Resultado do TratamentoRESUMO
BackgroundThe proprotein convertase subtilisin/kexin type 9 (PCSK9) has a key role in the regulation of plasma low-density lipoprotein (LDL) cholesterol by enhancing the degradation of LDL receptor. Functional variants in PCSK9 have been associated with differences in plasma lipids and may contribute to the variability of the response to cholesterol-lowering drugs.ObjectiveTo investigate the influence of PCSK9 variants on plasma lipid profile and response to atorvastatin in Brazilian subjects.MethodsPCSK9 E670G, I474V, and R46L single nucleotide polymorphisms (SNPs) and plasma lipids were evaluated in 163 hypercholesterolemics (HC) and 171 normolipidemics (NL). HC patients with indication for cholesterol-lowering drug therapy (n = 128) were treated with atorvastatin (10 mg/d/4 wk). PCSK9 SNPs were analyzed by real time polymerase chain reaction.ResultsFrequencies of the PCSK9 SNPs were similar between the HC and NL groups. Logistic regression analysis showed a trend of association between PCSK9 E670G and hypercholesterolemia after adjustment for covariates (P = .059). The 670G allele was associated with high basal levels of LDL cholesterol (P = .03) in HC patients using the extreme discordant phenotype method. No association tests were performed for R46L variant because of its very low frequency, whereas the I474V polymorphism and PCSK9 haplotypes were not related to hypercholesterolemia or variability on plasma lipids in both NL and HC groups (P > .05). LDL cholesterol reduction in response to atorvastatin was not influenced by PCSK9 genotypes or haplotypes.
Assuntos
Colesterol , Polimorfismo de Nucleotídeo ÚnicoRESUMO
BACKGROUND: The proprotein convertase subtilisin/kexin type 9 (PCSK9) has a key role in theregulation of plasma low-density lipoprotein (LDL) cholesterol by enhancing the degradation ofLDL receptor. Functional variants in PCSK9 have been associated with differences in plasma lipidsand may contribute to the variability of the response to cholesterol-lowering drugs.OBJECTIVE: To investigate the influence of PCSK9 variants on plasma lipid profile and response toatorvastatin in Brazilian subjects.METHODS: PCSK9 E670G, I474V, and R46L single nucleotide polymorphisms (SNPs) and plasmalipids were evaluated in 163 hypercholesterolemics (HC) and 171 normolipidemics (NL). HC patientswith indication for cholesterol-lowering drug therapy (n 5 128) were treated with atorvastatin (10 mg/d/4 wk). PCSK9 SNPs were analyzed by real time polymerase chain reaction.RESULTS: Frequencies of the PCSK9 SNPs were similar between the HC and NL groups. Logisticregression analysis showed a trend of association between PCSK9 E670G and hypercholesterolemiaafter adjustment for covariates (P 5 .059). The 670G allele was associated with high basal levels ofLDL cholesterol (P 5 .03) in HC patients using the extreme discordant phenotype method. Noassociation tests were performed for R46L variant because of its very low frequency, whereas theI474V polymorphism and PCSK9 haplotypes were not related to hypercholesterolemia or variabilityon plasma lipids in both NL and HC groups (P ..05). LDL cholesterol reduction in response to atorvastatinwas not influenced by PCSK9 genotypes or haplotypes.CONCLUSIONS: PCSK9 E670G polymorphism but not I474V contributes to the variability onplasma LDL cholesterol levels in hypercholesterolemic subjects. Both PCSK9 variants have no influenceon cholesterol-lowering response to atorvastatin. 2014 National Lipid Association. All rights reserved.
Assuntos
Colesterol , Farmacogenética , Polimorfismo GenéticoRESUMO
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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.
Assuntos
Anticolesterolemiantes/farmacologia , Citocromo P-450 CYP3A/metabolismo , Expressão Gênica/efeitos dos fármacos , Ácidos Heptanoicos/farmacologia , Hipercolesterolemia/tratamento farmacológico , Leucócitos Mononucleares/efeitos dos fármacos , Pirróis/farmacologia , Adulto , Idoso , Anticolesterolemiantes/uso terapêutico , Atorvastatina , Estudos de Casos e Controles , LDL-Colesterol/metabolismo , Citocromo P-450 CYP3A/genética , Esquema de Medicação , Feminino , Heterogeneidade Genética , Haplótipos , Ácidos Heptanoicos/uso terapêutico , Humanos , Hipercolesterolemia/genética , Hipercolesterolemia/metabolismo , Hipercolesterolemia/patologia , Leucócitos Mononucleares/metabolismo , Leucócitos Mononucleares/patologia , Masculino , Pessoa de Meia-Idade , Fenótipo , Pirróis/uso terapêutico , RNA Mensageiro/genética , RNA Mensageiro/metabolismoRESUMO
BACKGROUND: Balancing the subject composition of case and control groups to create homogenous ancestries between each group is essential for medical association studies. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
Assuntos
População Negra/genética , Estudos de Casos e Controles , Hipercolesterolemia/genética , Indígenas Sul-Americanos/etnologia , Polimorfismo de Nucleotídeo Único , População Urbana , Povo Asiático/etnologia , Povo Asiático/genética , População Negra/etnologia , Brasil/etnologia , Feminino , Humanos , Indígenas Sul-Americanos/genética , Masculino , Grupos Populacionais/etnologia , Grupos Populacionais/genética , População Branca/etnologia , População Branca/genéticaRESUMO
Osteoporotic hip fractures (OHF) are not limited to elderly; however, studies in non-elderly are scarce. Thus, the aim of this study was to evaluate co-morbidities in non-elderly patients with OHF in a Community Teaching Hospital. All hospitalizations due to OHF during a 3-year period in a Community Teaching Hospital were retrospectively evaluated for co-morbidities, and patients 18-64 years old were compared with those ≥65 years old. Of all hospitalizations, 232 (0.73%) were due to hip fractures, and 120/232 (51.7%) patients had OHF. The comparison of the 13 (10.8%) OHF patients <65 years old (47.3 ± 9.7 years) with 107 (89.2%) ≥65 years old (80.4 ± 7.7 years) revealed a male predominance (61.5 vs. 27.1%, P = 0.022) and a distinct ethnic distribution with a lower proportion of Caucasians in the former (61.5 vs. 86.9%, P = 0.033). Moreover, non-elderly OHF patients had higher frequencies of insulin-dependent DM (38.5 vs. 3.7%, P = 0.001) and alcoholism (38.5 vs. 4.7%, P = 0.001) than aged patients. In contrast, rates of age-related co-morbidities such as stroke (7.7 vs. 18.7%, P = 0.461), heart failure (23.1 vs. 14.0%, P = 0.411), and dementia (7.7 vs. 15.9%, P = 0.689) were comparable in both groups. Logistic regression analysis demonstrated that insulin-dependent DM (OR = 25.4, 95% CI = 4.7-136.8, P < 0.001) and alcoholism (OR = 20.3, 95% CI = 3.9-103.3, P < 0.001) remained as independent risk factors for OHF in non-elderly patients. Osteoporosis is an important cause of HF in Community Hospital. Non-elderly patients with OHF have a peculiar demographic profile and associated co-morbidities. These findings reinforce the need of early osteoporosis diagnosis and rigorous fracture prevention in patients with DM and alcoholism.
Assuntos
Fraturas do Quadril/epidemiologia , Osteoporose/epidemiologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Alcoolismo/epidemiologia , Brasil/epidemiologia , Doenças Cardiovasculares/epidemiologia , Distribuição de Qui-Quadrado , Comorbidade , Demência/epidemiologia , Diabetes Mellitus/epidemiologia , Feminino , Fraturas do Quadril/etnologia , Hospitais Comunitários , Hospitais de Ensino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Osteoporose/etnologia , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Adulto JovemRESUMO
Background: Balancing the subject composition of case and control groups to create homogenous ancestries between each group is essential for medical association studies. Methods: 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. Results: 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 0.50 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. Conclusions: 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.
Assuntos
Genômica , Polimorfismo Genético , População Urbana , População Urbana/classificaçãoRESUMO
BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.
Assuntos
Anticolesterolemiantes/uso terapêutico , Apolipoproteínas E/genética , Expressão Gênica , Ácidos Heptanoicos/uso terapêutico , Hipercolesterolemia/tratamento farmacológico , Leucócitos Mononucleares/metabolismo , Pirróis/uso terapêutico , RNA Mensageiro/genética , Adulto , Idoso , Apolipoproteínas E/metabolismo , Atorvastatina , Estudos de Casos e Controles , Feminino , Estudos de Associação Genética , Genótipo , Humanos , Leucócitos Mononucleares/efeitos dos fármacos , Lipídeos/sangue , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético , RNA Mensageiro/metabolismoRESUMO
Aims: The relationship between variants in SLCO1B1 and SLCO2B1 genes and lipid-lowering response to atorvastatin was investigated. Material and Methods: One-hundred-thirty-six unrelated individuals with hypercholesterolemia were selected andOPEN ACCESStreated 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. Results: 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%:1.38.0, p G polymorphism causes significant increase in atorvastatin response and may be an important marker for predicting efficacy of lipid-lowering therapy.
Assuntos
Farmacogenética , Polimorfismo de Nucleotídeo ÚnicoRESUMO
BACKGROUND: 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. METHODS: 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). RESULTS: 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. CONCLUSION: 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.
Assuntos
Ácidos Heptanoicos/uso terapêutico , Hipercolesterolemia/tratamento farmacológico , Hipercolesterolemia/genética , Lipídeos/sangue , Polimorfismo de Nucleotídeo Único/genética , Pirróis/uso terapêutico , Receptores Depuradores Classe B/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticolesterolemiantes/uso terapêutico , Apolipoproteína A-I/sangue , Apolipoproteínas B/sangue , Atorvastatina , Sangue/efeitos dos fármacos , Brasil , Colesterol/sangue , Colesterol/metabolismo , HDL-Colesterol/sangue , HDL-Colesterol/efeitos dos fármacos , HDL-Colesterol/genética , LDL-Colesterol/sangue , LDL-Colesterol/efeitos dos fármacos , LDL-Colesterol/genética , Feminino , Frequência do Gene/genética , Genótipo , Haplótipos/genética , Humanos , Hipercolesterolemia/sangue , Desequilíbrio de Ligação/genética , Metabolismo dos Lipídeos/efeitos dos fármacos , Metabolismo dos Lipídeos/genética , Masculino , Pessoa de Meia-Idade , Triglicerídeos/sangueRESUMO
BACKGROUND: The cytochrome P450 isoenzyme 3A5 (CYP3A5) has an important role on biotransformation of xenobiotics. CYP3A5 SNPs have been associated with variations on enzyme activity that can modify the metabolism of several drugs. METHODS: In order to evaluate the influence of CYP3A5 variants on response to lowering-cholesterol drugs, 139 individuals with hypercholesterolemia were selected. After a wash-out period of 4 weeks, individuals were treated with atorvastatin (10 mg/day/4 weeks). Genomic DNA was extracted by a salting-out procedure. CYP3A5*3C, CYP3A5*6 and CYP3A5*1D were analyzed by PCR-RFLP and DNA sequencing. RESULTS: >Frequencies of the CYP3A5*3C and CYP3A5*1D alleles were lower in individuals of African descent (*3C: 47.8% and *1D: 55.2%) than in non-Africans (*3C: 84.9% and *1D 84.8%, p<0.01). Non-Africans carrying *3A allele (*3C and *1D combined alleles) had lower total and LDL-cholesterol response to atorvastatin than non-*3A allele carriers (p<0.05). CONCLUSION: CYP3A5*3A allele is associated with reduced cholesterol-lowering response to atorvastatin in non-African individuals.
Assuntos
Citocromo P-450 CYP3A/genética , Ácidos Heptanoicos/uso terapêutico , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Hipercolesterolemia/tratamento farmacológico , Hipercolesterolemia/genética , Pirróis/uso terapêutico , Idoso , Alelos , Atorvastatina , População Negra , Índice de Massa Corporal , Brasil/epidemiologia , LDL-Colesterol/sangue , DNA/genética , Primers do DNA , Feminino , Frequência do Gene , Genótipo , Humanos , Hipercolesterolemia/epidemiologia , Masculino , Pessoa de Meia-Idade , Polimorfismo de Fragmento de Restrição , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
BACKGROUND: ABCA1 plays an important role in HDL metabolism. Single nucleotide polymorphisms (SNPs) in ABCA1 gene were associated with variation in plasma HDL-c. METHODS: The effect of the ABCA1 SNPs C-14T, R219K and of a novel variant C-105T on serum lipids was investigated in 367 unrelated Brazilian individuals (224 hypercholesterolemic and 143 normolipidemic). The relation between ABCA1 SNPs and the lipid-lowering response to atorvastatin (10 mg/day/4 weeks) was also evaluated in 141 hypercholesterolemic (HC) individuals. The polymorphisms were detected by PCR-RFLP and confirmed by DNA sequencing. RESULTS: Linkage disequilibrium was found between the SNPs C-105T and C-14T in the HC group. HC individuals carrying -105CT/TT genotypes had higher serum HDL-c and lower triglyceride and VLDL-c concentrations as well as lower TG/HDL-c ratio compared to the -105CC carriers (p<0.05). The R219K SNP was associated with reduced serum triglyceride, VLDL-c and TG/HDL-c ratio in the HC group (p<0.05), and with an increased serum apoAI in NL individuals. The effects of ABCA1 SNPs on basal serum lipids of HC individuals were not modified by atorvastatin treatment. CONCLUSIONS: The ABCA1 SNPs R219K and C-105T were associated with a less atherogenic lipid profile but not with the lowering-cholesterol response to atorvastatin in a Brazilian population.
Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Lipídeos/sangue , Polimorfismo de Nucleotídeo Único , Transportador 1 de Cassete de Ligação de ATP , Adulto , Sequência de Bases , Brasil , Primers do DNA , Feminino , Humanos , Desequilíbrio de Ligação , Masculino , Pessoa de Meia-IdadeRESUMO
PURPOSE: The effect of atorvastatin, an HMG-CoA reductase inhibitor, on expression and activity of the drug transporter ABCB1 in HepG2 cells and peripheral blood mononuclear cells (PBMCs) was examined. METHODS: Localization and expression of ABCB1 in hepatocytes was examined by indirect immunofluorescence. Expression of ABCB1 mRNA and ABCB1 activity were examined in atorvastatin-treated and control cells and PBMCs using real-time PCR and Rhodamine 123 efflux assay. RESULTS: Immunohistochemical analysis revealed that ABCB1 is located at the apical membrane of the bile canaliculi. Atorvastatin at 10 and 20 microM up-regulated ABCB1 expression resulting in a significant 1.4-fold increase of the protein levels. Treatment of HepG2 cells with 20 microM atorvastatin caused a 60% reduction on mRNA expression (p<0.05) and a 41% decrease in ABCB1-mediated efflux of Rhodamine123 (p<0.01) by flow cytometry. Correlation was found between ABCB1 mRNA levels and creatine kinase (r=0.30; p=0.014) and total cholesterol (r=-0.31; p=0.010). CONCLUSIONS. Atorvastatin leads to decreased ABCB1 function and modulates ABCB1 synthesis in HepG2 cells and in PBMCs. ABCB1 plays a role in cellular protection as well as in secretion and/or disposition, therefore, inhibition of ABCB1 synthesis may increase the atorvastatin efficacy, leading to a more pronounced reduction of plasma cholesterol.
Assuntos
Carcinoma Hepatocelular/metabolismo , Regulação para Baixo/efeitos dos fármacos , Ácidos Heptanoicos/farmacologia , Monócitos/metabolismo , Transportadores de Ânions Orgânicos/metabolismo , Pirróis/farmacologia , Subfamília B de Transportador de Cassetes de Ligação de ATP , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Atorvastatina , Sequência de Bases , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Primers do DNA , Citometria de Fluxo , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases , Imuno-Histoquímica , Transportadores de Ânions Orgânicos/sangue , RNA Mensageiro/genética , Rodamina 123/metabolismoRESUMO
OBJECTIVE: Sepsis is associated with increased production of superoxide and nitric oxide, with consequent peroxynitrite generation. Cardiodepression is induced in the heart during oxidative stress associated with septic shock. Oxidative and nitrosative stress can lead to activation of the nuclear enzyme poly(adenosine 5'-diphosphate [ADP]-ribose) polymerase (PARP), with subsequent loss of myocardial contractile function. The aim of the study was to investigate whether cardiodepression found in septic patients is associated with plasma markers of myocardial necrosis and with myocardial PARP activation. DESIGN: Prospective and observational study. SETTING: University hospital intensive care unit for clinical and surgical patients. PATIENTS: Twenty-five patients older than 18 yrs presenting with severe sepsis or septic shock. Patients with history of chronic heart failure, cancer, coronary artery disease, diabetes, or acquired immune deficiency syndrome were excluded. INTERVENTIONS: Patients were followed for 28 days, and biochemical and hemodynamic data were collected on days 1, 3, and 6 of sepsis. The groups were survivors and nonsurvivors, defined only after the end of clinical patient evolution. Heart sections from patients who died were analyzed with hematoxylin-eosin and Picro Sirius-Red immunostaining and with electron microscopy. MEASUREMENTS AND MAIN RESULTS: The study population included 25 individuals, of whom 12 (48%) died during the 6 days of follow-up. The initial data of the inflammation marker C-reactive protein and Acute Physiologic and Chronic Health. Evaluation severity were similar in both groups (nonsurvivors, 26 +/- 2; survivors, 24 +/- 5; NS). Overall, an increase in plasma troponin level was related to increased mortality risk. In patients who died, significant myocardial damage was detected, and histologic analysis of heart sections showed inflammatory infiltration, increased collagen deposition, and derangement of mitochondrial cristae. Immunohistochemical staining for poly(ADP-ribose) (PAR), the product of activated PARP, was demonstrated in septic hearts. There was a positive correlation between PAR staining densitometry and troponin I (r(2) = 0.73; p < .05), and the correlation of PAR staining densitometry and left ventricular systolic stroke work index was r(2) = 0.33 (p = .0509). CONCLUSION: There is significant PARP activation in the hearts of septic patients with impaired cardiac function. We hypothesize that PARP activation may be partly responsible for the cardiac depression seen in humans with severe sepsis.
Assuntos
Cardiomiopatias/etiologia , Poli(ADP-Ribose) Polimerases/fisiologia , Choque Séptico/complicações , Cardiomiopatias/enzimologia , Cardiomiopatias/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Contração Miocárdica , Estudos ProspectivosRESUMO
Modifications in chylomicron metabolism caused by antihypertensive drugs were investigated in hypertensive subjects because previous studies had indicated that diuretics and beta-blockers modify the plasma lipid concentrations through mechanisms that were not fully understood. A triglyceride-rich emulsion resembling lymph chylomicrons, labeled with (3H) triolein and (14C) cholesteryl oleate, was infused intravenously into mildly hypertensive patients after 8 weeks on placebo and subsequently on hydrochlorothiazide (n = 10) or propranolol (n = 8). The residence time of both radioactivities in plasma was utilized for the simultaneous calculation of the particle remnant removal rate and of the lipoprotein lipase activity expressed as a delipidation index = 1 - [(3H) triolein residence time/(14C) cholesteryl oleate residence time]. Treatment with hydrochlorothiazide diminished the delipidation rate value whereas propranolol mildly increased the removal rate of the remnant particle. These alterations of the chylomicron kinetics were not accompanied by changes in plasma triglycerides, glucose, and insulin concentration as measured in the fasting state. The impairment of the lipoprotein lipase activity by thiazides and the faster removal rate of the whole particle by propranolol could explain the reason why in previous clinical studies the simultaneous use of these drugs does not aggravate the hyperlipidemia known to be induced by thiazides alone.