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Pulipati VP, Alenghat FJ. The impact of lipid-lowering medications on coronary artery plaque characteristics. Am J Prev Cardiol 2021; 8:100294. [PMID: 34877559 PMCID: PMC8627965 DOI: 10.1016/j.ajpc.2021.100294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/29/2021] [Accepted: 11/06/2021] [Indexed: 11/28/2022] Open
Abstract
Atherosclerosis is the predominant cause of coronary artery disease. The last several decades have witnessed significant advances in lipid-lowering therapies, which comprise a central component of atherosclerotic cardiovascular disease prevention. In addition to cardiovascular risk reduction with dyslipidemia management, some lipid-based therapies show promise at the level of the atherosclerotic plaque itself through mechanisms governing lipid accumulation, plaque stability, local inflammation, endothelial dysfunction, and thrombogenicity. The capacity of lipid-lowering therapies to modify atherosclerotic plaque burden, size, composition, and vulnerability should correlate with their ability to reduce disease progression. This review discusses plaque characteristics, diagnostic modalities to evaluate these characteristics, and how they are altered by current and emerging lipid-lowering therapies, all in human coronary artery disease.
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Affiliation(s)
- Vishnu Priya Pulipati
- Section of Cardiology, University of Chicago Medicine, 5841 S. Maryland Avenue, MC 6080, Chicago, IL 60637, United States
| | - Francis J. Alenghat
- Section of Cardiology, University of Chicago Medicine, 5841 S. Maryland Avenue, MC 6080, Chicago, IL 60637, United States
- Pritzker School of Medicine, University of Chicago, Chicago, United States
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Davies SP, Mycroft-West CJ, Pagani I, Hill HJ, Chen YH, Karlsson R, Bagdonaite I, Guimond SE, Stamataki Z, De Lima MA, Turnbull JE, Yang Z, Vicenzi E, Skidmore MA, Khanim FL, Richardson A. The Hyperlipidaemic Drug Fenofibrate Significantly Reduces Infection by SARS-CoV-2 in Cell Culture Models. Front Pharmacol 2021; 12:660490. [PMID: 34421587 PMCID: PMC8377159 DOI: 10.3389/fphar.2021.660490] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 06/28/2021] [Indexed: 12/15/2022] Open
Abstract
The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic has caused a significant number of fatalities and worldwide disruption. To identify drugs to repurpose to treat SARS-CoV-2 infections, we established a screen to measure the dimerization of angiotensin-converting enzyme 2 (ACE2), the primary receptor for the virus. This screen identified fenofibric acid, the active metabolite of fenofibrate. Fenofibric acid also destabilized the receptor-binding domain (RBD) of the viral spike protein and inhibited RBD binding to ACE2 in enzyme-linked immunosorbent assay (ELISA) and whole cell-binding assays. Fenofibrate and fenofibric acid were tested by two independent laboratories measuring infection of cultured Vero cells using two different SARS-CoV-2 isolates. In both settings at drug concentrations, which are clinically achievable, fenofibrate and fenofibric acid reduced viral infection by up to 70%. Together with its extensive history of clinical use and its relatively good safety profile, this study identifies fenofibrate as a potential therapeutic agent requiring an urgent clinical evaluation to treat SARS-CoV-2 infection.
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Affiliation(s)
- Scott P Davies
- Institute for Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Courtney J Mycroft-West
- Molecular and Structural Bioscience, School of Life Sciences, Keele University, Staffordshire, United Kingdom
| | - Isabel Pagani
- Viral Pathogenesis and Biosafety Unit, San Raffaele Scientific Institute Via Olgettina, Milano, Italy
| | - Harriet J Hill
- Institute for Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Yen-Hsi Chen
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Richard Karlsson
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ieva Bagdonaite
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Scott E Guimond
- Molecular and Structural Bioscience, School of Life Sciences, Keele University, Staffordshire, United Kingdom
| | - Zania Stamataki
- Institute for Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Marcelo Andrade De Lima
- Molecular and Structural Bioscience, School of Life Sciences, Keele University, Staffordshire, United Kingdom
| | - Jeremy E Turnbull
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Zhang Yang
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Elisa Vicenzi
- Viral Pathogenesis and Biosafety Unit, San Raffaele Scientific Institute Via Olgettina, Milano, Italy
| | - Mark A Skidmore
- Molecular and Structural Bioscience, School of Life Sciences, Keele University, Staffordshire, United Kingdom
| | - Farhat L Khanim
- School of Biomedical Sciences, Institute for Clinical Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Alan Richardson
- School of Pharmacy and Bioengineering, Keele University, Staffordshire, United Kingdom
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The Glitazars Paradox: Cardiotoxicity of the Metabolically Beneficial Dual PPARα and PPARγ Activation. J Cardiovasc Pharmacol 2021; 76:514-526. [PMID: 33165133 DOI: 10.1097/fjc.0000000000000891] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The most common complications in patients with type-2 diabetes are hyperglycemia and hyperlipidemia that can lead to cardiovascular disease. Alleviation of these complications constitutes the major therapeutic approach for the treatment of diabetes mellitus. Agonists of peroxisome proliferator-activated receptor (PPAR) alpha and PPARγ are used for the treatment of hyperlipidemia and hyperglycemia, respectively. PPARs belong to the nuclear receptors superfamily and regulate fatty acid metabolism. PPARα ligands, such as fibrates, reduce circulating triglyceride levels, and PPARγ agonists, such as thiazolidinediones, improve insulin sensitivity. Dual-PPARα/γ agonists (glitazars) were developed to combine the beneficial effects of PPARα and PPARγ agonism. Although they improved metabolic parameters, they paradoxically aggravated congestive heart failure in patients with type-2 diabetes via mechanisms that remain elusive. Many of the glitazars, such as muraglitazar, tesaglitazar, and aleglitazar, were abandoned in phase-III clinical trials. The objective of this review article pertains to the understanding of how combined PPARα and PPARγ activation, which successfully targets the major complications of diabetes, causes cardiac dysfunction. Furthermore, it aims to suggest interventions that will maintain the beneficial effects of dual PPARα/γ agonism and alleviate adverse cardiac outcomes in diabetes.
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KLF4 Upregulation in Atherosclerotic Thoracic Aortas: Exploring the Protective Effect of Colchicine-based Regimens in a Hyperlipidemic Rabbit Model. Ann Vasc Surg 2021; 78:328-335. [PMID: 34182114 DOI: 10.1016/j.avsg.2021.04.040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 04/18/2021] [Accepted: 04/21/2021] [Indexed: 01/08/2023]
Abstract
BACKGROUND Inflammatory dysregulation of KLF4 is related to atheromatosis. In the present study, we explored the impact of colchicine-based regimens on the development of thoracic aortic atheromatosis and KLF4 expression. METHODS Twenty-eight New Zealand White rabbits were divided to 4 groups. The control group (n = 6) was fed standard chow, group A (n = 6) was fed chow enriched with 1% w/w cholesterol, group B (n = 8) was fed the same cholesterol-enriched diet plus 2 mg/kg body weight/day colchicine and 250 mg/kg body weight/day fenofibrate, while group C (n = 8) was also fed the same diet plus 2 mg/kg body weight/day colchicine and 15 mg/kg body weight/day N-acetylcysteine. After 7 weeks, all animals were euthanized, and their thoracic aortas were isolated. Atherosclerotic plaque area was estimated with morphometric analysis. KLF4 expression was quantified with quantitative RT-PCR. RESULTS Group A developed significantly more atherosclerosis compared to group B (MD: 13.67, 95% CI: 7.49-19.84) and C (MD: 20.29, 95% CI: 14.12-26.47). Colchicine with N-acetylcysteine resulted in more pronounced reduction in the extent of atherosclerotic plaques compared to colchicine/fibrate (MD: 6.62, 95% CI: 0.90-12.34). Group A exhibited significantly greater KLF4 expression compared to group B (MD: 4.94, 95% CI: 1.11-8.77) and C (MD: 9.94, 95% CI: 6.11-13.77). Combining colchicine with N-acetylcysteine instead of fenofibrate (MD: 5.00, 95% CI: 1.45-8.54) led to a more robust reduction in KLF4 expression. CONCLUSIONS In the present hyperlipidemic animal model, colchicine-based regimens curtailed de novo atherogenesis and KLF4 overexpression in thoracic aortas.
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Sahebkar A, Simental-Mendía LE, Katsiki N, Reiner Ž, Banach M, Pirro M, Atkin SL. Effect of fenofibrate on plasma apolipoprotein C-III levels: a systematic review and meta-analysis of randomised placebo-controlled trials. BMJ Open 2019; 8:e021508. [PMID: 30798284 PMCID: PMC6278807 DOI: 10.1136/bmjopen-2018-021508] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVES This meta-analysis of randomised placebo-controlled clinical trials aimed to assess the effect of fenofibrate on apolipoprotein C-III (apo C-III), a key regulator of triglyceride metabolism. MATERIALS AND METHODS Randomised placebo-controlled trials investigating the impact of fenofibrate treatment on apo C-III levels were searched in PubMed-Medline, Scopus, Web of Science and Google Scholar databases from inception to 18 August 2017. Quantitative data synthesis was determined by a random-effects model and generic inverse variance method. Sensitivity analysis was conducted using the leave-one-out method. A weighted random-effects meta-regression was performed to evaluate glycaemic parameter confounders. RESULTS Meta-analysis of 10 clinical trials involving 477 subjects showed fenofibrate therapy decreased apo C-III levels (weighted mean difference (WMD) -4.78 mg/dL, 95% CI -6.95 to -2.61, p<0.001; I266.87%). Subgroup analysis showed that fenofibrate reduced plasma apo C-III concentrations in subgroups of trials with treatment durations of either <12 weeks (WMD -4.50 mg/dL, p=0.001) or ≥12 weeks (WMD: -4.73 mg/dL, p=0.009) and doses of fenofibrate <200 mg/day (WMD -6.33 mg/dL, p<0.001) and >200 mg/day (p=0.006), with no significant difference between the subgroups. CONCLUSION This meta-analysis found that fenofibrate therapy significantly decreases apo C-III levels, an effect evident with both short-term treatment and doses less than 200 mg/day.
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Affiliation(s)
- Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
- Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
- School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Niki Katsiki
- Second Propedeutic Department of Internal Medicine, Medical School, Aristotle University of Thessaloniki, Hippocration Hospital, Thessaloniki, Greece
| | - Željko Reiner
- Department of Internal medicine, University Hospital Center Zagreb, University of Zagreb, Zagreb, Croatia
| | - Maciej Banach
- Department of Hypertension, WAM University Hospital in Lodz, Medical University of Lodz, Lodz, Poland
- Polish Mother's Memorial Hospital Research Institute (PMMHRI), Lodz, Poland
| | - Matteo Pirro
- Unit of Internal Medicine, Angiology and Arteriosclerosis Diseases, Department of Medicine, University of Perugia, Perugia, Italy
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Harmer JA, Keech AC, Veillard AS, Skilton MR, Watts GF, Celermajer DS. Fenofibrate effects on carotid artery intima-media thickness in adults with type 2 diabetes mellitus: A FIELD substudy. Diabetes Res Clin Pract 2018; 141:156-167. [PMID: 29763709 DOI: 10.1016/j.diabres.2018.05.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 04/16/2018] [Accepted: 05/08/2018] [Indexed: 11/16/2022]
Abstract
AIM Dyslipidemia in type 2 diabetes contributes to an increased risk of cardiovascular disease. Fenofibrate, a lipid-regulating peroxisome proliferator-activated receptor-α (PPARα) agonist, has been shown to reduce vascular complications in adults with type 2 diabetes. The mechanisms for such benefit, however, are not yet well understood. We examined the effects of fenofibrate on carotid intima-media thickness (IMT), a marker of subclinical atherosclerosis, in adults with type 2 diabetes. METHODS In a prospectively designed substudy of the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study, we assessed carotid IMT in a subset of 422 representative adults. Traditional risk factors and IMT were assessed at 2 and 4 years after randomisation to fenofibrate (200 mg daily) or placebo. The prespecified primary study endpoint was the difference in IMT between treatment groups at 4 years. Post-hoc analyses were performed according to dyslipidemia and metabolic syndrome status. RESULTS There was no difference in carotid IMT comparing those assigned to fenofibrate or placebo at 2 or 4 years, despite statistically significant improvement in lipid and lipoprotein parameters at 2 and 4 years, including TC, LDL-C and TG, and HDL-C at 4 months and 2 years. Similarly, there was no difference in carotid IMT on fenofibrate compared with placebo in those with dyslipidemia or metabolic syndrome. CONCLUSIONS Fenofibrate was not associated with improved carotid IMT in adults with type 2 diabetes when compared with placebo, despite a statistically significant improvement in TC, LDL-C and TG at 2 and 4 years, and HDL-C at 4 months and 2 years.
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Affiliation(s)
- Jason A Harmer
- Sydney Medical School, University of Sydney, Sydney, NSW, Australia; Department of Cardiology, Royal North Shore Hospital, Sydney, NSW, Australia; Faculty of Medicine, Western Sydney University, Sydney, NSW, Australia.
| | - Anthony C Keech
- Sydney Medical School, University of Sydney, Sydney, NSW, Australia; Department of Cardiology, Royal Prince Alfred Hospital, Sydney, NSW, Australia; NHMRC Clinical Trials Center, University of Sydney, Sydney, NSW, Australia
| | | | - Michael R Skilton
- Sydney Medical School, University of Sydney, Sydney, NSW, Australia; Department of Cardiology, Royal Prince Alfred Hospital, Sydney, NSW, Australia
| | - Gerald F Watts
- Lipid Disorders Clinic, Department of Cardiology, Royal Perth Hospital, Perth, WA, Australia; School of Medicine and Pharmacology, University of Western Australia, Perth, WA, Australia
| | - David S Celermajer
- Sydney Medical School, University of Sydney, Sydney, NSW, Australia; Department of Cardiology, Royal Prince Alfred Hospital, Sydney, NSW, Australia
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Yang AN, Zhang HP, Sun Y, Yang XL, Wang N, Zhu G, Zhang H, Xu H, Ma SC, Zhang Y, Li GZ, Jia YX, Cao J, Jiang YD. High-methionine diets accelerate atherosclerosis by HHcy-mediated FABP4 gene demethylation pathway via DNMT1 in ApoE−/−
mice. FEBS Lett 2015; 589:3998-4009. [DOI: 10.1016/j.febslet.2015.11.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 11/12/2015] [Accepted: 11/13/2015] [Indexed: 11/25/2022]
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Abstract
Atherosclerosis is a chronic inflammatory disease with deposition of excessive cholesterol in the arterial intima. Peroxisome proliferator-activated receptor α (PPARα) is a nuclear receptor that can activate or inhibit the expression of many target genes by forming a heterodimer complex with the retinoid X receptor. Activation of PPARα plays an important role in the metabolism of multiple lipids, including high-density lipoprotein, cholesterol, low-density lipoprotein, triglyceride, phospholipid, bile acids, and fatty acids. Increased PPARα activity also mitigates atherosclerosis by blocking macrophage foam cell formation, vascular inflammation, vascular smooth muscle cell proliferation and migration, plaque instability, and thrombogenicity. Clinical use of synthetic PPARα agonist fibrate improved dyslipidemia and attenuated atherosclerosis-related disease risk. This review summarizes PPARα in lipid and lipoprotein metabolism and atherosclerosis, and also highlights its potential therapeutic benefits.
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Cao H, Wen G, Li H. Role of peroxisome proliferator-activated receptor α in atherosclerosis. Mol Med Rep 2014; 9:1755-60. [PMID: 24604149 DOI: 10.3892/mmr.2014.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 02/19/2014] [Indexed: 11/05/2022] Open
Abstract
Atherosclerosis is an inflammatory disease involving the immune response. In addition to lowering the cholesterol level, the peroxisome proliferator-activated receptor α (PPAR-α) can prevent atherosclerosis via its pleiotropic anti-inflammatory effects. However, the role of PPAR-α in modulating inflammatory progression of atherosclerosis has rarely been studied. Thus, we aimed to investigate the role of PPAR-α in atherosclerosis by evaluating the expression of inflammatory cytokines induced by PPAR-α in an in vivo rabbit model. New Zealand White rabbits were randomly divided into 5 groups: control, high-fat diet + balloon injury, high-fat diet + balloon injury + placebo, high-fat diet + balloon injury + fenofibrate, and high-fat diet + balloon injury + WY-14643. The femoral arteries of rabbits were balloon-injured after initiation of the high-fat diet and before administration of fenofibrate, WY-14643 or placebo solution. Atherosclerosis was induced by high-fat diet and balloon angioplasty, and the vessel wall lumen occlusion was determined by measuring the stenosis rate. PPAR-α gene expression was examined by quantitative polymerase chain reaction analysis. The cellular localization and distribution of PPAR-α was observed by immunohistochemistry, and its protein level was assessed by western blot analysis. The production of interleukin-10 (IL-10), tumor necrosis factor-α (TNF-α) and P-selectin, which are major inflammatory factors involved in atherosclerosis, was monitored by an enzyme-linked immunosorbent assay (ELISA). Treatment with PPAR-α agonists (fenofibrate or WY-14643) reduced the vascular occlusion rate, as compared to the high-fat diet + balloon injury and the placebo groups. Furthermore, the expression of PPAR-α at both the protein and the mRNA level was increased in the fenofibrate and WY-14643 groups. According to the results, the TNF-α and P-selectin levels were reduced in the fenofibrate and WY-14643 groups. These results suggest that PPAR-α activation can attenuate the effects of atherosclerosis by inhibiting the expression of major inflammatory factors in a rabbit atherosclerosis model.
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Affiliation(s)
- Heng Cao
- Department of Cardiology, Shanghai First People's Hospital, College of Medicine, Shanghai Jiaotong University, Shanghai 200080, P.R. China
| | - Gao Wen
- Department of Cardiology, Shanghai First People's Hospital, College of Medicine, Shanghai Jiaotong University, Shanghai 200080, P.R. China
| | - Hongli Li
- Department of Cardiology, Shanghai First People's Hospital, College of Medicine, Shanghai Jiaotong University, Shanghai 200080, P.R. China
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Fournier N, Tuloup-Minguez V, Pourci ML, Thérond P, Jullian JC, Wien F, Leroy M, Dallongeville J, Paul JL, Leroy A. Fibrate treatment induced quantitative and qualitative HDL changes associated with an increase of SR-BI cholesterol efflux capacities in rabbits. Biochimie 2013; 95:1278-87. [DOI: 10.1016/j.biochi.2013.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 02/01/2013] [Indexed: 11/28/2022]
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Cheng SM, Chu KM, Lai JH. The modulatory mechanisms of fenofibrate on human primary T cells. Eur J Pharm Sci 2010; 40:316-24. [DOI: 10.1016/j.ejps.2010.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 04/07/2010] [Accepted: 04/10/2010] [Indexed: 10/19/2022]
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Potential health-modulating effects of isoflavones and metabolites via activation of PPAR and AhR. Nutrients 2010; 2:241-79. [PMID: 22254019 PMCID: PMC3257647 DOI: 10.3390/nu2030241] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 02/23/2010] [Indexed: 12/24/2022] Open
Abstract
Isoflavones have multiple actions on cell functions. The most prominent one is the activation of estrogen receptors. Other functions are often overlooked, but are equally important and explain the beneficial health effects of isoflavones. Isoflavones are potent dual PPARα/γ agonists and exert anti-inflammatory activity, which may contribute to the prevention of metabolic syndrome, atherosclerosis and various other inflammatory diseases. Some isoflavones are potent aryl hydrocarbon receptor (AhR) agonists and induce cell cycle arrest, chemoprevention and modulate xenobiotic metabolism. This review discusses effects mediated by the activation of AhR and PPARs and casts a light on the concerted action of isoflavones.
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Zulli A, Hare DL. High dietary methionine plus cholesterol stimulates early atherosclerosis and late fibrous cap development which is associated with a decrease in GRP78 positive plaque cells. Int J Exp Pathol 2009; 90:311-20. [PMID: 19563613 DOI: 10.1111/j.1365-2613.2009.00649.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The role of homocysteine, or its precursor methionine, in the formation of fibrous caps and its association with endoplasmic reticulum (ER) stress is unclear. Homocysteine can stimulate collagen accumulation and upregulate the ER stress chaperone glucose regulated protein 78 (GRP78). The aim of this study was to determine if high dietary methionine would increase fibrous caps, and that removal of an atherogenic diet would decrease the amount of ER stressed cells. New Zealand white rabbits were fed for 2, 4, or 12 weeks an atherogenic diet [1% methionine + 0.5% cholesterol (2MC, 4MC or 12MC)]; for 4 or 12 weeks a 0.5% cholesterol diet (4Ch, 12Ch); and to study plaque regression, an MC diet for 2 or 4 weeks accompanied by 10 weeks of a normal diet (2MCr, 4MCr). Endothelial function, atherosclerosis and GRP78 positive cells were studied. Endothelial function was abolished in 4MC and atherosclerosis increased 17-fold (P < 0.05) compared with 4Ch. Fibrous caps composed 48% of total plaque area in 12MC vs. 10% in 12Ch (P < 0.01), and 12MC expressed less GRP78 plaque cells vs. 12Ch (P < 0.01). Four MCr had less plaque GRP78 cells than 12MC (P < 0.05) and less endothelial GRP78 cells (P < 0.01). In addition, GRP78 positive cells were the highest in 4MC, but decreased in all other groups (P < 0.01). GRP78 positive cells within the fibrous cap inversely correlated with cap size (r(2) = 0.9). These studies suggest that high dietary methionine could be beneficial for plaque stabilisation, and a normal diet also stabilises plaque and decreases the number of stressed plaque cells.
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Affiliation(s)
- Anthony Zulli
- Departments of Cardiology and Medicine, University of Melbourne, Austin Health, Australia.
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