RESUMO
Cellular mechanisms that mediate steatohepatitis, an increasingly prevalent condition in the Western world for which no therapies are available, are poorly understood. Despite the fact that its synthetic agonists induce fatty liver, the liver X receptor (LXR) transcription factor remains a target of interest because of its anti-atherogenic, cholesterol removal, and anti-inflammatory activities. Here we show that tetratricopeptide repeat domain protein 39B (Ttc39b, C9orf52) (T39), a high-density lipoprotein gene discovered in human genome-wide association studies, promotes the ubiquitination and degradation of LXR. Chow-fed mice lacking T39 (T39(-/-)) display increased high-density lipoprotein cholesterol levels associated with increased enterocyte ATP-binding cassette transporter A1 (Abca1) expression and increased LXR protein without change in LXR messenger RNA. When challenged with a high fat/high cholesterol/bile salt diet, T39(-/-) mice or mice with hepatocyte-specific T39 deficiency show increased hepatic LXR protein and target gene expression, and unexpectedly protection from steatohepatitis and death. Mice fed a Western-type diet and lacking low-density lipoprotein receptor (Ldlr(-/-)T39(-/-)) show decreased fatty liver, increased high-density lipoprotein, decreased low-density lipoprotein, and reduced atherosclerosis. In addition to increasing hepatic Abcg5/8 expression and limiting dietary cholesterol absorption, T39 deficiency inhibits hepatic sterol regulatory element-binding protein 1 (SREBP-1, ADD1) processing. This is explained by an increase in microsomal phospholipids containing polyunsaturated fatty acids, linked to an LXRα-dependent increase in expression of enzymes mediating phosphatidylcholine biosynthesis and incorporation of polyunsaturated fatty acids into phospholipids. The preservation of endogenous LXR protein activates a beneficial profile of gene expression that promotes cholesterol removal and inhibits lipogenesis. T39 inhibition could be an effective strategy for reducing both steatohepatitis and atherosclerosis.
Assuntos
Aterosclerose/genética , Fígado Gorduroso/genética , Lipoproteínas HDL/deficiência , Lipoproteínas HDL/genética , Receptores Nucleares Órfãos/metabolismo , Transportador 1 de Cassete de Ligação de ATP/metabolismo , Membro 5 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Membro 8 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Aterosclerose/prevenção & controle , Aterosclerose/terapia , Ácidos e Sais Biliares/metabolismo , Colesterol na Dieta/metabolismo , HDL-Colesterol/metabolismo , Dieta Hiperlipídica , Ácidos Graxos Insaturados/metabolismo , Fígado Gorduroso/prevenção & controle , Fígado Gorduroso/terapia , Feminino , Regulação da Expressão Gênica , Hepatócitos/metabolismo , Ligantes , Lipogênese/genética , Lipoproteínas/metabolismo , Lipoproteínas HDL/metabolismo , Lipoproteínas LDL/metabolismo , Receptores X do Fígado , Masculino , Camundongos , Receptores Nucleares Órfãos/genética , Fosfatidilcolinas/biossíntese , Fosfatidilcolinas/metabolismo , Estabilidade Proteica , Proteólise , Receptores de LDL/deficiência , Receptores de LDL/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , UbiquitinaçãoRESUMO
OBJECTIVE: Reverse cholesterol transport (RCT) is a major mechanism by which HDL (high-density lipoprotein) protects against atherosclerosis. Endothelial lipase (EL) reportedly reduces HDL levels, which, in theory, would increase atherosclerosis. However, it remains unclear whether EL affects RCT in vivo. APPROACH AND RESULTS: Adenoviral vectors expressing EL or luciferase were intravenously injected into mice, and a macrophage RCT assay was performed. As expected, hepatic EL overexpression markedly reduced HDL levels. In parallel, plasma 3H-cholesterol counts from the EL-expressing mice decreased by 85% compared with control. Surprisingly, there was no difference in fecal 3H-cholesterol excretion between the groups. Kinetic studies revealed increased catabolism/hepatic uptake of 3HDL-cholesteryl ether, resulting in no change in fecal HDL-cholesteryl ester excretion in the mice. To explore underlying mechanisms for the preservation of RCT despite low HDL levels in the EL-expressing mice, we investigated the effects of hepatic SR-BI (scavenger receptor class B type I) knockdown. RCT assay revealed that knockdown of SR-BI alone reduced fecal excretion of macrophage-derived 3H-cholesterol. Interestingly, hepatic EL overexpression under SR-BI inhibition further attenuated fecal tracer counts as compared with control. Finally, we observed that EL overexpression enhanced in vivo RCT under pharmacological inhibition of hepatic ABCA1 (ATP-binding cassette transporter A1) by probucol. CONCLUSIONS: Hepatic EL expression compensates for reduced macrophage-derived cholesterol efflux to plasma because of low HDL levels by promoting cholesterol excretion to bile/feces via an SR-BI pathway, maintaining overall RCT in vivo. In contrast, EL-modified HDL might negatively regulate RCT via hepatic ABCA1. Despite extreme hypoalphalipoproteinemia, RCT is maintained in EL-expressing mice via SR-BI/ABCA1-dependent pathways.
Assuntos
Transportador 1 de Cassete de Ligação de ATP/metabolismo , HDL-Colesterol/sangue , Lipase/biossíntese , Fígado/enzimologia , Macrófagos Peritoneais/metabolismo , Receptores Depuradores Classe B/metabolismo , Adenoviridae/genética , Animais , Indução Enzimática , Técnicas de Transferência de Genes , Vetores Genéticos , Células Hep G2 , Humanos , Lipase/genética , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/genética , MicroRNAs/metabolismo , Células RAW 264.7 , Interferência de RNA , Receptores Depuradores Classe B/genéticaRESUMO
OBJECTIVE: Oxidized products of probucol, spiroquinone and diphenoquinone, were shown to increase cell cholesterol release and plasma high-density lipoprotein (HDL) by inhibiting degradation of ATP-binding cassette transporter A1. We investigated whether these compounds enhance reverse cholesterol transport in mice. APPROACH AND RESULTS: Spiroquinone and diphenoquinone increased ATP-binding cassette transporter A1 protein (2.8- and 2.6-fold, respectively, P<0.01) and apolipoprotein A-I-mediated cholesterol release (1.4- and 1.4-fold, P<0.01 and P<0.05, respectively) in RAW264.7 cells. However, diphenoquinone, but not spiroquinone, enhanced cholesterol efflux to HDL (+12%, P<0.05), whereas both increased ATP-binding cassette transporter G1 protein, by 1.8- and 1.6-fold, respectively. When given orally to mice, both compounds significantly increased plasma HDL-cholesterol, by 19% and 20%, respectively (P<0.05), accompanied by an increase in hepatic and macrophage ATP-binding cassette transporter A1 but not ATP-binding cassette transporter G1. We next evaluated in vivo reverse cholesterol transport by injecting RAW264.7 cells labeled with (3)H-cholesterol intraperitoneally into mice. Both spiroquinone and diphenoquinone increased fecal excretion of the macrophage-derived (3)H-tracer, by 25% and 28% (P<0.01 and P<0.05), respectively. spiroquinone/diphenoquinone did not affect fecal excretion of HDL-derived (3)H-cholesterol, implying that macrophage-to-plasma was the most important step in spiroquinone/diphenoquinone-mediated promotion of in vivo reverse cholesterol transport. Finally, spiroquinone significantly reduced aortic atherosclerosis in apolipoprotein E null mice when compared with the vehicle. CONCLUSIONS: Spiroquinone and diphenoquinone increase functional ATP-binding cassette transporter A1 in both the macrophages and the liver, elevate plasma HDL-cholesterol, and promote overall reverse cholesterol transport in vivo. These compounds are promising as therapeutic reagents against atherosclerosis.
Assuntos
Transportador 1 de Cassete de Ligação de ATP/efeitos dos fármacos , Androstadienos/farmacologia , Anticolesterolemiantes/farmacologia , Aorta/efeitos dos fármacos , Doenças da Aorta/prevenção & controle , Aterosclerose/prevenção & controle , Colesterol/sangue , Hipercolesterolemia/tratamento farmacológico , Macrófagos/efeitos dos fármacos , Probucol/farmacologia , Quinonas/farmacologia , Transportador 1 de Cassete de Ligação de ATP/metabolismo , Animais , Aorta/metabolismo , Aorta/patologia , Doenças da Aorta/sangue , Doenças da Aorta/genética , Doenças da Aorta/patologia , Apolipoproteína A-I/sangue , Apolipoproteínas E/deficiência , Apolipoproteínas E/genética , Aterosclerose/sangue , Aterosclerose/genética , Aterosclerose/patologia , Transporte Biológico , HDL-Colesterol/sangue , Modelos Animais de Doenças , Fezes/química , Hipercolesterolemia/sangue , Hipercolesterolemia/genética , Fígado/efeitos dos fármacos , Fígado/metabolismo , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Oxirredução , Placa Aterosclerótica , Células RAW 264.7 , Fatores de TempoRESUMO
Reverse cholesterol transport (RCT) is pivotal in the return of excess cholesterol from peripheral tissues to the liver for excretion in bile and eventually feces. RCT from macrophages is a critical anti-atherogenicity mechanism of HDL. As the cholesterol absorption inhibitor ezetimibe promoted RCT in mice, which lack cholesterol ester transfer protein (CETP), we investigated its effects in hamsters, which have CETP. A high-cholesterol diet (HC) increased cholesterol levels throughout lipoprotein fractions and ezetimibe markedly reduced VLDL/LDL cholesterol levels under both normal chow (NC) and HC. However, ezetimibe did not affect and reduced HDL-cholesterol levels under NC and HC, respectively. Intraperitoneal injection of (3)H-cholesterol pre-labeled macrophages in an in vivo RCT assay increased tracer accumulation in the liver but reduced it in bile under HC, and these changes were completely cancelled by ezetimibe. Under both NC and HC, ezetimibe reduced tracer levels in the liver but increased them in feces, indicating promotion of RCT in vivo. We performed a RCT assay using hamsters subjected to bile duct ligation (BDL) to clarify whether a transintestinal cholesterol efflux (TICE) pathway contributes to ezetimibe's enhancement of RCT. BDL markedly inhibited macrophage-derived (3)H-cholesterol excretion to feces and cancelled ezetimibe's stimulatory effect on RCT, suggesting that biliary cholesterol excretion is a major contributor in RCT promotion by ezetimibe but the contribution of the TICE pathway is minimal. In conclusions, ezetimibe exerts an additive anti-atherogenic property by enhancing RCT in hamsters. Our findings suggest that this property is independent of the TICE pathway.
Assuntos
Anticolesterolemiantes/farmacologia , Azetidinas/farmacologia , Bile/efeitos dos fármacos , HDL-Colesterol/metabolismo , Fígado/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Animais , Bile/metabolismo , Ductos Biliares/cirurgia , Transporte Biológico/efeitos dos fármacos , Proteínas de Transferência de Ésteres de Colesterol/metabolismo , LDL-Colesterol/metabolismo , VLDL-Colesterol/metabolismo , Cricetinae , Dieta , Ezetimiba , Fezes/química , Fígado/metabolismo , Macrófagos/citologia , Macrófagos/metabolismo , Masculino , TrítioRESUMO
OBJECTIVE: Low-density lipoprotein receptor (LDLR) is degraded by inducible degrader of LDLR (Idol) and protein convertase subtilisin/kexin type 9 (PCSK9), thereby regulating circulating LDL levels. However, it remains unclear whether, and if so how, these LDLR degraders affect each other. We therefore investigated effects of liver-specific expression of Idol on LDL/PCSK9 metabolism in mice and hamsters. APPROACH AND RESULTS: Injection of adenoviral vector expressing Idol (Ad-Idol) induced a liver-specific reduction in LDLR expression which, in turn, increased very-low-density lipoprotein/LDL cholesterol levels in wild-type mice because of delayed LDL catabolism. Interestingly, hepatic Idol overexpression markedly increased plasma PCSK9 levels. In LDLR-deficient mice, plasma PCSK9 levels were already elevated at baseline and unchanged by Idol overexpression, which was comparable with the observation for Ad-Idol-injected wild-type mice, indicating that Idol-induced PCSK9 elevation depended on LDLR. In wild-type mice, but not in LDLR-deficient mice, Ad-Idol enhanced hepatic PCSK9 expression, with activation of sterol regulatory element-binding protein 2 and subsequently increased expression of its target genes. Supporting in vivo findings, Idol transactivated PCSK9/LDLR in sterol regulatory element-binding protein 2/LDLR-dependent manners in vitro. Furthermore, an in vivo kinetic study using (125)I-labeled PCSK9 revealed delayed clearance of circulating PCSK9, which could be another mechanism. Finally, to extend these findings into cholesteryl ester transfer protein-expressing animals, we repeated the above in vivo experiments in hamsters and obtained similar results. CONCLUSIONS: A vicious cycle in LDLR degradation might be generated by PCSK9 induced by hepatic Idol overexpression via dual mechanisms: sterol regulatory element-binding protein 2/LDLR. Furthermore, these effects would be independent of cholesteryl ester transfer protein expression.
Assuntos
Fígado/metabolismo , Pró-Proteína Convertases/sangue , Receptores de LDL/fisiologia , Serina Endopeptidases/sangue , Transdução de Sinais , Proteína de Ligação a Elemento Regulador de Esterol 2/fisiologia , Ubiquitina-Proteína Ligases/fisiologia , Animais , Proteínas de Transferência de Ésteres de Colesterol/fisiologia , Cricetinae , Células Hep G2 , Humanos , Lipoproteínas LDL/metabolismo , Receptores X do Fígado , Mesocricetus , Camundongos , Camundongos Endogâmicos C57BL , Receptores Nucleares Órfãos/fisiologia , Pró-Proteína Convertase 9 , Pró-Proteína Convertases/fisiologia , Serina Endopeptidases/fisiologiaRESUMO
Stearoyl-coenzyme A desaturase 1 (SCD1) is the rate-limiting enzyme in the synthesis of monounsaturated fatty acids. However, the impact of SCD1 on atherosclerosis remains unclear. The aim of this study was to determine whether SCD1 affects macrophage reverse cholesterol transport (RCT) in mice. Compared to the control, adenoviral-mediated SCD1 overexpression in RAW264.7 macrophages increased cholesterol efflux to HDL, but not to apoA-I, without clear changes in ABCA1, ABCG1 and SR-BI expressions. While knockdown of ABCG1 and SR-BI did not affect the SCD1-induced cholesterol efflux to HDL, SCD1-overexpressing macrophages promoted the formation of both normal- and large-sized HDL in media, accompanying increased apolipoprotein A-I levels in HDL fractions. Transformation to larger particles of HDL was independently confirmed by nuclear magnetic resonance-based lipoprotein analysis. Interestingly, media transfer assays revealed that HDL generated by SCD1 had enhanced cholesterol efflux potential, indicating that SCD1 transformed HDL to a more anti-atherogenic phenotype. To study macrophage RCT in vivo, (3)H-cholesterol-labeled RAW264.7 cells overexpressing SCD1 or the control were intraperitoneally injected into mice. Supporting the in vitro data, injection of SCD1-macrophages resulted in significant increases in (3)H-tracer in plasma, liver, and feces compared to the control. Moreover, there was a shift towards larger particles in the (3)H-tracer distribution of HDL fractions obtained from the mice. In conclusion, macrophage-specific SCD1 overexpression promotes overall RCT through increased cholesterol efflux to HDL, suggesting that macrophage SCD1 achieves an anti-atherogenic effect by enhancing RCT.
Assuntos
Colesterol/metabolismo , Regulação Enzimológica da Expressão Gênica , Lipoproteínas HDL/metabolismo , Macrófagos/enzimologia , Estearoil-CoA Dessaturase/biossíntese , Transportador 1 de Cassete de Ligação de ATP , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Aterosclerose/enzimologia , Aterosclerose/genética , Aterosclerose/patologia , Aterosclerose/terapia , Transporte Biológico Ativo/genética , Linhagem Celular , Colesterol/genética , Humanos , Lipoproteínas/genética , Lipoproteínas/metabolismo , Lipoproteínas HDL/genética , Macrófagos/patologia , Camundongos , Estearoil-CoA Dessaturase/genéticaRESUMO
Reverse cholesterol transport (RCT) is a mechanism critical to the anti-atherogenic property of HDL. Although citrulline contributes to the amelioration of atherosclerosis via endothelial nitric oxide production, it remains unclear whether it affects RCT. This study was undertaken to clarify the effects of citrulline on expressions of specific transporters such as ATP binding cassette transporters (ABC)A1 and ABCG1, and the cholesterol efflux from macrophages to apolipoprotein (apo) A-I or HDL in vitro and ex vivo. Citrulline increased ABCA1 and ABCG1 mRNA and protein levels in THP-1 macrophages, translating into enhanced apoA-I- and HDL-mediated cholesterol efflux. In the human crossover study, 8 healthy male volunteers (age 30-49 years) consumed either 3.2 g/day citrulline or placebo for 1 week. Citrulline consumption brought about significant increases in plasma levels of citrulline and arginine. Supporting the in vitro data, monocyte-derived macrophages (MDM) differentiated under autologous post-citrulline sera demonstrated enhancement of both apoA-I- and HDL-mediated cholesterol efflux through increased ABCA1 and ABCG1 expressions, compared to MDM differentiated under pre-citrulline sera. However, the placebo did not modulate these parameters. Therefore, in addition to improving endothelium function, citrulline might have an anti-atherogenic property by increasing RCT of HDL.
RESUMO
ABC transporter G1 (ABCG1) plays a pivotal role in HDL-mediated cholesterol efflux and atherogenesis. We investigated whether, and how, retinoic acid receptors (RARs) regulate ABCG1 expression in macrophages. All-trans retinoic acid (ATRA), an RAR ligand, increased ABCG1 protein levels and apoA-I/HDL-mediated cholesterol efflux from the macrophages. Both ATRA and other RAR agonists, TTNPB and Am580, increased major transcripts driven by promoter B upstream of exon 5, though minor transcripts driven by promoter A upstream of exon 1 were only increased by ATRA. The stimulatory effects of ATRA on ABCG1 expression were completely abolished in the presence of RAR/RXR antagonists but were only partially canceled in the presence of an LXR antagonist. Adenovirus with overexpressed oxysterol sulfotransferase abolished the LXR pathway, as previously reported, and ATRA-responsiveness in ABCA1/ABCG1 expressions were respectively attenuated by 38 and 22% compared to the control virus. Promoter assays revealed that ABCG1 levels were regulated more by promoter B than promoter A, and ATRA activated promoter B in a liver X receptor-responsive element (LXRE)-dependent manner. Further, LXRE-B in intron 7, but not LXRE-A in intron 5, enhanced ATRA responsiveness under overexpression of all RAR isoforms-RARα/ß/γ. In contrast, the activation of promoter B by TTNPB depended on LXRE-B and RARα, but not on RARß/γ. Finally, chromatin immunoprecipitation and gel-shift assays revealed a specific and direct repeat 4-dependent binding of RARα to LXRE-B. In conclusion, RAR ligands increase ABCA1/G1 expression and apoA-I/HDL-mediated cholesterol efflux from macrophages, and modulate ABCG1 promoter activity via LXRE-dependent mechanisms.
Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Macrófagos/efeitos dos fármacos , Receptores do Ácido Retinoico/agonistas , Tretinoína/farmacologia , Transportador 1 de Cassete de Ligação de ATP , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/genética , Animais , Benzoatos/farmacologia , Transporte Biológico/efeitos dos fármacos , Western Blotting , Células COS , Linhagem Celular , Chlorocebus aethiops , Colesterol/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Células HEK293 , Humanos , Receptores X do Fígado , Macrófagos/citologia , Macrófagos/metabolismo , Modelos Genéticos , Receptores Nucleares Órfãos/agonistas , Receptores Nucleares Órfãos/genética , Receptores Nucleares Órfãos/metabolismo , Regiões Promotoras Genéticas/genética , Ligação Proteica/efeitos dos fármacos , Receptores do Ácido Retinoico/genética , Receptores do Ácido Retinoico/metabolismo , Elementos de Resposta/genética , Receptores X de Retinoides/agonistas , Receptores X de Retinoides/genética , Receptores X de Retinoides/metabolismo , Retinoides/farmacologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos , Tetra-Hidronaftalenos/farmacologiaRESUMO
Endothelium-bound extracellular superoxide dismutase (eEC-SOD), a major antioxidative enzyme in the vasculature, is involved in anti-atherogenesis by inhibiting low-density lipoprotein (LDL) oxidation. The objective was to investigate whether the polyphenol-rich juar tea had beneficial effects on LDL oxidation and eEC-SOD levels in patients with metabolic syndrome (MetS). A total of 20 men with MetS participated in a randomized cross-over trial, comparing consumption of five cups/day of juar tea with that of a polyphenol-poor tea, barley tea, for 4 weeks. Although there was no change in LDL oxidizability after consumption of either tea, juar tea significantly increased eEC-SOD levels by 16% (p < 0.05), whereas barley tea significantly decreased levels by 15% (p < 0.05). It is noteworthy that the changes in eEC-SOD were positively associated with those in LDL oxidizability after tea consumption (r(2) = 0.11, p < 0.05). Tea polyphenols may provide anti-atherosclerotic effects by inhibiting LDL oxidation through EC-SOD bound to the endothelium.
Assuntos
Camellia sinensis/química , Endotélio Vascular/efeitos dos fármacos , Lipoproteínas LDL/metabolismo , Síndrome Metabólica/tratamento farmacológico , Fitoterapia , Polifenóis/uso terapêutico , Superóxido Dismutase/metabolismo , Adulto , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Aterosclerose/metabolismo , Aterosclerose/prevenção & controle , Endotélio Vascular/metabolismo , Hordeum , Humanos , Masculino , Síndrome Metabólica/metabolismo , Oxirredução , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Polifenóis/farmacologia , Chá/químicaRESUMO
RATIONALE: Association of habitual coffee consumption with coronary heart disease morbidity and mortality has not been established. We hypothesized that coffee may enhance reverse cholesterol transport (RCT) as the antiatherogenic properties of high-density lipoprotein (HDL). OBJECTIVE: This study was to investigate whether the phenolic acids of coffee and coffee regulates RCT from macrophages in vitro, ex vivo and in vivo. METHODS AND RESULTS: Caffeic acid and ferulic acid, the major phenolic acids of coffee, enhanced cholesterol efflux from THP-1 macrophages mediated by HDL, but not apoA-I. Furthermore, these phenolic acids increased both the mRNA and protein levels of ATP-binding cassette transporter (ABC)G1 and scavenger receptor class B type I (SR-BI), but not ABCA1. Eight healthy volunteers were recruited for the ex vivo study, and blood samples were taken before and 30 minutes after consumption of coffee or water in a crossover study. The mRNA as well as protein levels of ABCG1, SR-BI, and cholesterol efflux by HDL were increased in the macrophages differentiated under autologous sera obtained after coffee consumption compared to baseline sera. Finally, effects of coffee and phenolic acid on in vivo RCT were assessed by intraperitoneally injecting [(3)H]cholesterol-labeled acetyl low-density lipoprotein-loaded RAW264.7 cells into mice, then monitoring appearance of (3)H tracer in plasma, liver, and feces. Supporting in vitro and ex vivo data, ferulic acid was found to significantly increase the levels of (3)H tracer in feces. CONCLUSIONS: Coffee intake might have an antiatherogenic property by increasing ABCG1 and SR-BI expression and enhancing HDL-mediated cholesterol efflux from the macrophages via its plasma phenolic acids.
Assuntos
Bebidas , Ácidos Cafeicos/farmacologia , Colesterol/metabolismo , Café , Ácidos Cumáricos/farmacologia , Lipoproteínas HDL/metabolismo , Macrófagos/efeitos dos fármacos , Transportador 1 de Cassete de Ligação de ATP , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Adulto , Animais , Apolipoproteína A-I/metabolismo , Bile/metabolismo , Transporte Biológico , Ácidos Cafeicos/sangue , Linhagem Celular , Colesterol/sangue , Doença das Coronárias/metabolismo , Doença das Coronárias/prevenção & controle , Ácidos Cumáricos/sangue , Estudos Cross-Over , Relação Dose-Resposta a Droga , Fezes/química , Feminino , Genes Reporter , Humanos , Lipoproteínas HDL/sangue , Lipoproteínas LDL/metabolismo , Fígado/metabolismo , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , RNA Mensageiro/metabolismo , Receptores Depuradores Classe B/genética , Receptores Depuradores Classe B/metabolismo , Fatores de Tempo , Transfecção , Regulação para CimaRESUMO
OBJECTIVE: ATP-binding cassette transporter A1 (ABCA1) and ABCG1 are key molecules in an initial step of reverse cholesterol transport (RCT), a major antiatherogenic property of high-density lipoprotein (HDL). The ubiquitin-proteasome system (UPS) mediates nonlysosomal pathways for protein degradation and is known to be involved in atherosclerosis. However, little is known about the effects of the UPS on these molecules and overall RCT. We therefore investigated whether UPS inhibition affects ABCA1/G1 expression in macrophages and RCT in vitro and in vivo. METHODS AND RESULTS: Various proteasome inhibitors increased ABCA1/G1 expression in macrophages, translating into enhanced apolipoprotein A-I- and HDL-mediated cholesterol efflux from macrophages. ABCA1 and ABCG1 were found to undergo polyubiquitination in the macrophages and HEK293 cells overexpressing these proteins, and pulse-chase analysis revealed that proteasome inhibitors inhibited ABCA1/G1 protein degradation. In in vivo experiments, the proteasome inhibitor bortezomib increased ABCA1/G1 protein levels in mouse peritoneal macrophages, and RCT assays showed that it significantly increased the fecal (54% increase compared with saline) and plasma (23%) appearances of the tracer derived from intraperitoneally injected (3)H-cholesterol-labeled macrophages. CONCLUSIONS: The present study provided evidence that the UPS is involved in ABCA1/G1 degradation, thereby affecting RCT in vivo. Therefore, specific inhibition of the UPS pathway might lead to a novel HDL therapy that enhances RCT.
Assuntos
Transportadores de Cassetes de Ligação de ATP/fisiologia , Colesterol/metabolismo , Lipoproteínas/fisiologia , Macrófagos/metabolismo , Complexo de Endopeptidases do Proteassoma/fisiologia , Transportador 1 de Cassete de Ligação de ATP , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/análise , Animais , Apolipoproteína A-I/fisiologia , Ácidos Borônicos/farmacologia , Bortezomib , Células Cultivadas , Células Hep G2 , Humanos , Lipoproteínas/análise , Lipoproteínas HDL/fisiologia , Camundongos , Fosforilação , Inibidores de Proteassoma , Pirazinas/farmacologia , Ubiquitina-Proteína Ligases/fisiologia , UbiquitinaçãoRESUMO
AIMS: Inflammation is involved in various processes of atherosclerosis development. Serum C-reactive protein (CRP) levels, a predictor for cardiovascular risk, are reportedly reduced by statins. However, several studies have demonstrated that CRP is a bystander during atherogenesis. While S100A12 has been focused on as an inflammatory molecule, it remains unclear whether statins affect circulating S100A12 levels. Here, we investigated whether atorvastatin treatment affected S100A12 and which biomarkers were correlated with changes in arterial inflammation. METHODS: We performed a prospective, randomized open-labeled trial on whether atorvastatin affected arterial (carotid and thoracic aorta) inflammation using 18fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) and inflammatory markers. Thirty-one statin-naïve patients with carotid atherosclerotic plaques were randomized to either a group receiving dietary management (n=15) or one receiving atorvastatin (10mg/day, n=16) for 12weeks. 18F-FDG-PET/CT and flow-mediated vasodilation (FMD) were performed, the latter to evaluate endothelial function. RESULTS: Atorvastatin, but not the diet-only treatment, significantly reduced LDL-cholesterol (LDL-C, -43%), serum CRP (-37%) and S100A12 levels (-28%) and improved FMD (+38%). 18F-FDG-PET/CT demonstrated that atorvastatin, but not the diet-only treatment, significantly reduced accumulation of 18F-FDG in the carotid artery and thoracic aorta. A multivariate analysis revealed that reduction in CRP, S100A12, LDL-C, oxidized-LDL, and increase in FMD were significantly associated with reduced arterial inflammation in the thoracic aorta, but not in the carotid artery. CONCLUSIONS: Atorvastatin treatment reduced S100A12/CRP levels, and the changes in these circulating markers mirrored the improvement in arterial inflammation. Our observations suggest that S100A12 may be an emerging therapeutic target for atherosclerosis.
Assuntos
Arterite , Aterosclerose , Inibidores de Hidroximetilglutaril-CoA Redutases , Placa Aterosclerótica , Aterosclerose/metabolismo , Atorvastatina/uso terapêutico , Biomarcadores , Artérias Carótidas/diagnóstico por imagem , Artérias Carótidas/metabolismo , LDL-Colesterol/metabolismo , Fluordesoxiglucose F18 , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Inflamação/tratamento farmacológico , Placa Aterosclerótica/tratamento farmacológico , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Estudos Prospectivos , Proteína S100A12RESUMO
AIM: The ATP binding cassette transporters A1 and G1 (ABCA1/G1) and scavenger receptor class B type I (SR-BI) are key molecules in cholesterol efflux and atherogenesis. These genes are regulated by peroxisome proliferator-activated receptor gamma (PPARgamma) and liver X receptor (LXR). Telmisartan is an angiotensin type 1 receptor blocker which has been reported to act as a ligand for PPARgamma. We investigated whether PPARgamma-activating ARBs affect the expression of these genes and cholesterol efflux from macrophages. METHODS AND RESULTS: Telmisartan increased ABCA1, ABCG1 and SR-BI mRNA levels in THP-1 macrophages in a dose- and time-dependent fashion. It also increased their protein levels and enhanced apoA-I- and HDL-mediated cholesterol efflux from macrophages. The knockdown of PPARgamma by siRNA abolished the telmisartan-induced expression of these genes. The knockdown of LXRalpha resulted in the complete and partial abolishment of telmisartan-induced ABCA1 and ABCG1 expression, respectively. We also demonstrated that telmisartan-induced SR-BI expression was dependent on the PPARgamma pathway but not on the LXRalpha pathway. A luciferase assay using an ABCA1 promoter construct showed that telmisartan activated ABCA1 transcription, which was abolished if the LXR binding element was mutated, indicating that increased ABCA1 transcription by telmisartan is LXR-dependent. CONCLUSION: Our results showed that telmisartan enhanced both apoA-I- and HDL-mediated cholesterol efflux from macrophages by increasing ABCA1, ABCG1 and SR-BI expression via PPARgamma-dependent and LXR-dependent/independent pathways.
Assuntos
Inibidores da Enzima Conversora de Angiotensina/farmacologia , Benzimidazóis/farmacologia , Benzoatos/farmacologia , Colesterol/metabolismo , Regulação da Expressão Gênica , Macrófagos/efeitos dos fármacos , PPAR gama/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Apolipoproteína A-I/genética , Apolipoproteína A-I/metabolismo , Células Cultivadas , Proteínas de Ligação a DNA/antagonistas & inibidores , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Humanos , Lipoproteínas HDL/metabolismo , Receptores X do Fígado , Macrófagos/metabolismo , Receptores Nucleares Órfãos , PPAR gama/antagonistas & inibidores , PPAR gama/genética , RNA Interferente Pequeno/farmacologia , Receptores Citoplasmáticos e Nucleares/antagonistas & inibidores , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores Depuradores Classe B/genética , Receptores Depuradores Classe B/metabolismo , TelmisartanRESUMO
Massive hemoptysis is a medical emergency and needs immediate treatment. It occurs in a wide variety of pulmonary diseases and typically originates from the bronchial arteries. We herein report a very rare case of a patient bleeding from a right phrenic artery-to-pulmonary artery fistula accompanied with focal bronchiectasis in the right middle lobe of the lung. In this case, multi-detector computed tomography was useful for clarifying the etiology and the abnormal anastomosis and facilitated effective angiographic embolization.
Assuntos
Fístula Artério-Arterial/complicações , Artérias Brônquicas/patologia , Hemoptise/etiologia , Pulmão/patologia , Artéria Pulmonar/patologia , Idoso de 80 Anos ou mais , Angiografia , Fístula Artério-Arterial/terapia , Embolização Terapêutica/métodos , Feminino , Hemoptise/terapia , Humanos , Tomografia Computadorizada por Raios X/efeitos adversosRESUMO
OBJECTIVE: Although previous randomized clinical trials established a basis for lipid guidelines worldwide, they employed fixed doses of statins throughout trials (fire-and-forget approach). In the real clinical setting, however, statin doses are titrated to achieve target low-density lipoprotein cholesterol (LDL-C) levels (treat-to-target approach). The major objective was to investigate whether intensive lipid-lowering therapy using the treat-to-target approach yielded greater regression of aortic plaques. METHODS: We therefore performed a prospective, randomized trial comparing the effects of standard (achieve LDL-C levels recommended by the Japanese guidelines) and intensive (achieve 30% lower LDL-C levels than standard) rosuvastatin therapy for 1 year in 60 hypercholesterolemic patients with a primary endpoint of aortic atherosclerotic plaques evaluated by non-invasive magnetic resonance imaging (MRI). RESULTS: Average doses were 2.9 ± 3.1 and 6.5 ± 5.1 mg/day for standard (n = 29) and intensive therapy group (n = 31), respectively. Although both therapies significantly reduced LDL-C and high-sensitivity C-reactive protein (hsCRP) levels, LDL-C reduction was significantly greater in the intensive group (-46 vs. -34%). MRI study showed that thoracic aortic plaques were significantly regressed in both groups, with greater regression of thoracic plaque in the intensive group (-9.1 vs. -3.2%, p = 0.01). Multivariate analyses revealed that thoracic plaque regression was significantly correlated with hsCRP reduction, but not with changes in serum lipids, endothelial function, or doses of rosuvastatin. CONCLUSION: Intensive statin therapy with titration targeting lower LDL-C levels resulted in greater thoracic aortic plaque regression compared to standard therapy, which was correlated with hsCRP reduction, suggesting that intensive statin therapy could provide better clinical outcomes.
Assuntos
Proteína C-Reativa/metabolismo , LDL-Colesterol/sangue , Fluorbenzenos/uso terapêutico , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Placa Aterosclerótica/tratamento farmacológico , Placa Aterosclerótica/patologia , Pirimidinas/uso terapêutico , Sulfonamidas/uso terapêutico , Idoso , Antropometria , Aorta/patologia , Aterosclerose , Endotélio Vascular/metabolismo , Feminino , Guias como Assunto , Humanos , Lipídeos/sangue , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Rosuvastatina Cálcica , Resultado do TratamentoRESUMO
BACKGROUND: Endothelial dysfunction is an independent predictor for cardiovascular events in patients with type 2 diabetes (T2DM). Glucagon like peptide-1 (GLP-1) reportedly exerts vasodilatory actions, and inhibitors of dipeptidyl peptidase-4 (DPP-4), an enzyme-degrading GLP-1, are widely used to treat T2DM. We therefore hypothesized that DPP-4 inhibitors (DPP-4Is) improve endothelial function in T2DM patients and performed 2 prospective, randomized crossover trials to compare the DPP-4I sitagliptin and an α-glucosidase inhibitor, voglibose (in study 1) and the DPP-4Is sitagliptin and alogliptin (in study 2). METHODS AND RESULTS: In study 1, 24 men with T2DM (46±5 years) were randomized to sitagliptin or voglibose for 6 weeks without washout periods. Surprisingly, sitagliptin significantly reduced flow-mediated vasodilatation (FMD; -51% compared with baseline, P<0.05) of the brachial artery despite improved diabetic status. In contrast, voglibose did not affect FMD. To confirm this result and determine whether it is a class effect, we conducted another trial (study 2) to compare sitagliptin and alogliptin in 42 T2DM patients (66±8 years) for 6 weeks with 4-week washout periods. Both DPP-4Is improved glycemic control but significantly attenuated FMD (7.2/4.3%, P<0.001, before/after sitagliptin; 7.0/4.8%, P<0.001, before/after alogliptin, respectively). Interestingly, FMD reduction was less evident in subjects who were on statins or whose LDL cholesterol levels were reduced by them, but this was not correlated with parameters including DPP-4 activity and GLP-1 levels or diabetic parameters. CONCLUSIONS: Our 2 independent trials demonstrated that DPP-4 inhibition attenuated endothelial function as evaluated by FMD in T2DM patients. This unexpected unfavorable effect may be a class effect of DPP-4Is. CLINICAL TRIAL REGISTRATION: URL: http://center.umin.ac.jp, Unique Identifiers: UMIN000005682 (sitagliptin versus voglibose) and UMIN000005681 (sitagliptin versus alogliptin).
Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Inibidores da Dipeptidil Peptidase IV/efeitos adversos , Endotélio Vascular/efeitos dos fármacos , Inositol/análogos & derivados , Piperidinas/efeitos adversos , Pirazinas/efeitos adversos , Triazóis/efeitos adversos , Uracila/análogos & derivados , Vasodilatação/efeitos dos fármacos , Adulto , Idoso , Biomarcadores/sangue , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , LDL-Colesterol/sangue , Estudos Cross-Over , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/enzimologia , Diabetes Mellitus Tipo 2/fisiopatologia , Endotélio Vascular/fisiopatologia , Feminino , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Inositol/efeitos adversos , Japão , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fluxo Sanguíneo Regional , Fosfato de Sitagliptina , Fatores de Tempo , Resultado do Tratamento , Uracila/efeitos adversosRESUMO
ATP-binding cassette transporters (ABC) A1 and G1 are key molecules in cholesterol efflux from macrophages, which is an initial step of reverse cholesterol transport (RCT), a major anti-atherogenic property of high-density lipoprotein (HDL). Astaxanthin is one of the naturally occurring carotenoids responsible for the pink-red pigmentation in a variety of living organisms. Although astaxanthin is known to be a strong antioxidant, it remains unclear through what mechanism of action it affects cholesterol homeostasis in macrophages. We therefore investigated the effects of astaxanthin on cholesterol efflux and ABCA1/G1 expressions in macrophages. Astaxanthin enhanced both apolipoprotein (apo) A-I- and HDL-mediated cholesterol efflux from RAW264.7 cells. In supporting these enhanced cholesterol efflux mechanisms, astaxanthin promoted ABCA1/G1 expression in various macrophages. In contrast, peroxisome proliferator-activated receptor γ, liver X receptor (LXR) α and LXRß levels remained unchanged by astaxanthin. An experiment using actinomycin D demonstrated that astaxanthin transcriptionally induced ABCA1/G1 expression, and oxysterol depletion caused by overexpression of cholesterol sulfotransferase further revealed that these inductions in ABCA1/G1 were independent of LXR-mediated pathways. Finally, we performed luciferase assays using human ABCA1/G1 promoter-reporter constructs to reveal that astaxanthin activated both promoters irrespective of the presence or absence of LXR-responsive elements, indicating LXR-independence of these activations. In conclusion, astaxanthin increased ABCA1/G1 expression, thereby enhancing apoA-I/HDL-mediated cholesterol efflux from the macrophages in an LXR-independent manner. In addition to the anti-oxidative properties, the potential cardioprotective properties of astaxanthin might therefore be associated with an enhanced anti-atherogenic function of HDL.
Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Colesterol/metabolismo , Expressão Gênica/efeitos dos fármacos , Lipoproteínas/genética , Macrófagos/metabolismo , Transportador 1 de Cassete de Ligação de ATP , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/fisiologia , Animais , Antioxidantes , Apolipoproteína A-I/efeitos dos fármacos , Apolipoproteína A-I/fisiologia , Cardiotônicos , Linhagem Celular , Lipoproteínas/fisiologia , Lipoproteínas HDL/efeitos dos fármacos , Lipoproteínas HDL/fisiologia , Receptores X do Fígado , Macrófagos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Receptores Nucleares Órfãos/fisiologia , Xantofilas/farmacologiaRESUMO
AIMS: Endothelin-1 (ET-1) contributes to the pathogenesis of cardiovascular diseases with multiple properties such as vasoconstriction. Human ET-1 gene expression is up-regulated by the transcription factor hypoxia-inducible factor-1 (HIF-1) through hypoxia response element (HRE). Although previous studies suggested that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) alter HIF-1-related gene expression, it remained unclear whether statins modulate HIF-1-mediated ET-1 expression. Therefore, we investigated the effect of fluvastatin on hypoxia-induced human ET-1 expression in vascular smooth muscle cells (VSMC). METHODS AND RESULTS: Hypoxia (1% O(2)), compared with the normoxic condition (21% O(2)), significantly induced the expression of preproET-1 mRNA, ET-1 protein, and ET-1 secretion in VSMC. Hypoxia induced a 2.3-fold increase in HRE-dependent ET-1 reporter gene activation. Under concentrations of 1 µmol/L or greater, fluvastatin attenuated the hypoxia-induced ET-1 gene expression through the accelerated ubiquitin/proteasome-dependent degradation of HIF-1α, thus consequently attenuating HIF-1α binding to the HRE of the ET-1 gene. These inhibitory effects of fluvastatin were cancelled by concomitant treatment with mevalonate, farnesyl pyrophosphate, or geranylgeranyl pyrophosphate, but not squalene. CONCLUSION: The present study suggests that fluvastatin attenuates HIF-1-dependent ET-1 gene expression in conjunction with the stimulation of HIF-1α ubiquitin/proteasome-dependent degradation via isoprenoid-dependent mechanisms.
Assuntos
Endotelina-1/metabolismo , Ácidos Graxos Monoinsaturados/farmacologia , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Indóis/farmacologia , Miócitos de Músculo Liso/metabolismo , Células Cultivadas , Fluvastatina , Humanos , Hipóxia/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Proteólise/efeitos dos fármacos , Fatores de TranscriçãoRESUMO
OBJECTIVE: Pioglitazone, a peroxisome proliferator-activated receptor γ (PPARγ) agonist, reportedly reduces cardiovascular events in diabetic patients. ATP cassette binding transporters (ABC) A1 and G1 are pivotal molecules for cholesterol efflux (ChE) from macrophages and high density-lipoprotein biogenesis, and the A1 transporter is regulated by a PPARγ-liver receptor X (LXR) pathway. Also, pioglitazone induces ABCG1 expression, though the exact mechanism remains unclear. We therefore investigated the effects of pioglitazone on ABCA1/G1 expression in vitro and ex vivo. METHODS: The effects of pioglitazone on ChE and ABCA1/G1 expressions in macrophages were assessed. Then, mRNA was quantified in macrophages when PPARγ/LXR inhibition by siRNA or overexpression of oxysterol sulfotransferase was performed. ABCA1/G1 promoter activity with mutated LXR-responsive elements was also measured. As an ex vivo study, 15 type 2 diabetic patients were administered pioglitazone or placebo, and ChE assays and protein expressions were determined using macrophages cultured with the corresponding sera. RESULTS: Pioglitazone increased LXRα/ABCA1/G1 expressions, which enhanced ChE from macrophages. Inhibition of PPARγ/LXR pathways revealed that LXR was primarily involved in pioglitazone's transactivation of ABCA1 but only partially involved for ABCG1. Promoter assays showed that ABCG1 was regulated more by the promoter in intron 4 than that upstream of exon 1 but both promoters were responsive to LXR activation. Sera obtained after pioglitazone treatment promoted ChE and ABCA1/G1 expressions in macrophages. CONCLUSION: Pioglitazone enhanced ChE from macrophages by increasing ABCA1/G1 in LXR-dependent and -independent manners. Our comparable in vitro and ex vivo results shed new light on pioglitazone's novel anti-atherogenic property.
Assuntos
Transportadores de Cassetes de Ligação de ATP/biossíntese , Colesterol/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Hipoglicemiantes/farmacologia , Macrófagos/fisiologia , Receptores Nucleares Órfãos/biossíntese , PPAR gama/metabolismo , Tiazolidinedionas/farmacologia , Transportador 1 de Cassete de Ligação de ATP , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Células Cultivadas , Células HEK293 , Humanos , Receptores X do Fígado , Macrófagos/efeitos dos fármacos , Pioglitazona , Interferência de RNARESUMO
AIM: Reverse cholesterol transport (RCT) is a critical mechanism for the anti-atherogenic property of HDL. The inhibitory effect of the sulfonylurea agent (SUA) glibenclamide on ATP binding-cassette transporter (ABC) A1 may decrease HDL function but it remains unclear whether it attenuates RCT in vivo. We therefore investigated how the SUAs glibenclamide and glimepiride affected the functionality of ABCA1/ABCG1 and scavenger receptor class B type I (SR-BI) expression in macrophages in vitro and overall RCT in vivo. METHODS: RAW264.7, HEK293 and BHK-21 cells were used for in vitro studies. To investigate RCT in vivo, 3H-cholesterol-labeled and acetyl LDL-loaded RAW264.7 cells were injected into mice. RESULTS: High dose (500µM) of glibenclamide inhibited ABCA1 function and apolipoprotein A-I (apoA-I)-mediated cholesterol efflux, and attenuated ABCA1 expression. Although glimepiride maintained apoA-I-mediated cholesterol efflux from RAW264.7 cells, like glibenclamide, it inhibited ABCA1-mediated cholesterol efflux from transfected HEK293 cells. Similarly, the SUAs inhibited SR-BI-mediated cholesterol efflux from transfected BHK-21 cells. High doses of SUAs increased ABCG1 expression in RAW264.7 cells, promoting HDL-mediated cholesterol efflux in an ABCG1-independent manner. Low doses (0.1-100 µM) of SUAs did not affect cholesterol efflux from macrophages despite dose-dependent increases in ABCA1/G1 expression. Furthermore, they did not change RCT or plasma lipid levels in mice. CONCLUSION: High doses of SUAs inhibited the functionality of ABCA1/SR-BI, but not ABCG1. At lower doses, they had no unfavorable effects on cholesterol efflux or overall RCT in vivo. These results indicate that SUAs do not have adverse effects on atherosclerosis contrary to previous findings for glibenclamide.