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Westerhout J, den Heijer-Jordaan A, Princen HMG, Stierum R. A systems toxicology approach for identification of disruptions in cholesterol homeostasis after aggregated exposure to mixtures of perfluorinated compounds in humans. Toxicol Sci 2024; 198:191-209. [PMID: 38243716 DOI: 10.1093/toxsci/kfae006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2024] Open
Abstract
Per- and polyfluoroalkyl substances (PFAS) are used in various household and industrial products. In humans, positive associations were reported between PFAS, including perfluorsulfonic acid and perfluorooctanoic acid, and cholesterol, a cardiometabolic risk factor. Animal studies show the opposite. Human-centered approaches are needed to better understand the effects of PFAS mixtures on cholesterol. Here, a systems toxicology approach is described, using a gene-centered cholesterol biokinetic model. PFAS exposure-gene expression relations from published data were introduced into the model. An existing PFAS physiologically based kinetic model was augmented with lung and dermal compartments and integrated with the cholesterol model to enable exposure-effect modeling. The final model was populated with data reflecting lifetime mixture exposure from: tolerable weekly intake values; the environment; high occupational exposures (ski waxing, PFAS industry). Results indicate that low level exposures (tolerable weekly intake, environmental) did not change cholesterol. In contrast, occupational exposures clearly resulted in internal PFAS exposure and disruption of cholesterol homeostasis, largely in line with epidemiological observations. Despite model limitations (eg, dynamic range, directionality), changes in cholesterol homeostasis were predicted for ski waxers, hitherto unknown from epidemiological studies. Here, future studies involving lipid metabolism could improve risk assessment.
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Affiliation(s)
- Joost Westerhout
- TNO Risk Analysis for Products in Development, 3584 CB Utrecht, The Netherlands
| | | | | | - Rob Stierum
- TNO Risk Analysis for Products in Development, 3584 CB Utrecht, The Netherlands
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2
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Fragki S, Dirven H, Fletcher T, Grasl-Kraupp B, Bjerve Gützkow K, Hoogenboom R, Kersten S, Lindeman B, Louisse J, Peijnenburg A, Piersma AH, Princen HMG, Uhl M, Westerhout J, Zeilmaker MJ, Luijten M. Systemic PFOS and PFOA exposure and disturbed lipid homeostasis in humans: what do we know and what not? Crit Rev Toxicol 2021; 51:141-164. [PMID: 33853480 DOI: 10.1080/10408444.2021.1888073] [Citation(s) in RCA: 82] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Associations between per- and polyfluoroalkyl substances (PFASs) and increased blood lipids have been repeatedly observed in humans, but a causal relation has been debated. Rodent studies show reverse effects, i.e. decreased blood cholesterol and triglycerides, occurring however at PFAS serum levels at least 100-fold higher than those in humans. This paper aims to present the main issues regarding the modulation of lipid homeostasis by the two most common PFASs, PFOS and PFOA, with emphasis on the underlying mechanisms relevant for humans. Overall, the apparent contrast between human and animal data may be an artifact of dose, with different molecular pathways coming into play upon exposure to PFASs at very low versus high levels. Altogether, the interpretation of existing rodent data on PFOS/PFOA-induced lipid perturbations with respect to the human situation is complex. From a mechanistic perspective, research on human liver cells shows that PFOS/PFOA activate the PPARα pathway, whereas studies on the involvement of other nuclear receptors, like PXR, are less conclusive. Other data indicate that suppression of the nuclear receptor HNF4α signaling pathway, as well as perturbations of bile acid metabolism and transport might be important cellular events that require further investigation. Future studies with human-relevant test systems would help to obtain more insight into the mechanistic pathways pertinent for humans. These studies shall be designed with a careful consideration of appropriate dosing and toxicokinetics, so as to enable biologically plausible quantitative extrapolations. Such research will increase the understanding of possible perturbed lipid homeostasis related to PFOS/ PFOA exposure and the potential implications for human health.
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Affiliation(s)
- Styliani Fragki
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Hubert Dirven
- Department of Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Tony Fletcher
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England (PHE), Chilton, UK
| | - Bettina Grasl-Kraupp
- Institute of Cancer Research, Medical University of Vienna, Borschkegasse 8a, Vienna, Austria
| | | | - Ron Hoogenboom
- Wageningen Food Safety Research (WFSR), Wageningen, The Netherlands
| | - Sander Kersten
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
| | - Birgitte Lindeman
- Department of Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Jochem Louisse
- Wageningen Food Safety Research (WFSR), Wageningen, The Netherlands
| | - Ad Peijnenburg
- Wageningen Food Safety Research (WFSR), Wageningen, The Netherlands
| | - Aldert H Piersma
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.,Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Hans M G Princen
- Metabolic Health Research, The Netherlands Organization of Applied Scientific Research (TNO), Gaubius Laboratory, Leiden, The Netherlands
| | - Maria Uhl
- Environment Agency Austria (EAA), Vienna, Austria
| | - Joost Westerhout
- Risk Analysis for Products In Development, The Netherlands Organization of Applied Scientific Research (TNO), Utrecht, The Netherlands
| | - Marco J Zeilmaker
- Centre for Nutrition, Prevention and Health Services, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Mirjam Luijten
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
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3
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Yoshida M, Nakamura K, Miyoshi T, Yoshida M, Kondo M, Akazawa K, Kimura T, Ohtsuka H, Ohno Y, Miura D, Ito H. Combination therapy with pemafibrate (K-877) and pitavastatin improves vascular endothelial dysfunction in dahl/salt-sensitive rats fed a high-salt and high-fat diet. Cardiovasc Diabetol 2020; 19:149. [PMID: 32979918 PMCID: PMC7520032 DOI: 10.1186/s12933-020-01132-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 09/18/2020] [Indexed: 11/25/2022] Open
Abstract
Background Statins suppress the progression of atherosclerosis by reducing low-density lipoprotein (LDL) cholesterol levels. Pemafibrate (K-877), a novel selective peroxisome proliferator-activated receptor α modulator, is expected to reduce residual risk factors including high triglycerides (TGs) and low high-density lipoprotein (HDL) cholesterol during statin treatment. However, it is not known if statin therapy with add-on pemafibrate improves the progression of atherosclerosis. The aim of this study was to assess the effect of combination therapy with pitavastatin and pemafibrate on lipid profiles and endothelial dysfunction in hypertension and insulin resistance model rats. Methods Seven-week-old male Dahl salt-sensitive (DS) rats were divided into the following five treatment groups (normal diet (ND) plus vehicle, high-salt and high-fat diet (HD) plus vehicle, HD plus pitavastatin (0.3 mg/kg/day), HD plus pemafibrate (K-877) (0.5 mg/kg/day), and HD plus combination of pitavastatin and pemafibrate) and treated for 12 weeks. At 19 weeks, endothelium-dependent relaxation of the thoracic aorta in response to acetylcholine was evaluated. Results After feeding for 12 weeks, systolic blood pressure and plasma levels of total cholesterol were significantly higher in the HD-vehicle group compared with the ND-vehicle group. Combination therapy with pitavastatin and pemafibrate significantly reduced systolic blood pressure, TG levels, including total, chylomicron (CM), very LDL (VLDL), HDL-TG, and cholesterol levels, including total, CM, VLDL, and LDL-cholesterol, compared with vehicle treatment. Acetylcholine caused concentration-dependent relaxation of thoracic aorta rings that were pre-contracted with phenylephrine in all rats. Relaxation rates in the HD-vehicle group were significantly lower compared with the ND-vehicle group. Relaxation rates in the HD-combination of pitavastatin and pemafibrate group significantly increased compared with the HD-vehicle group, although neither medication alone ameliorated relaxation rates significantly. Western blotting experiments showed increased phosphorylated endothelial nitric oxide synthase protein expression in aortas from rats in the HD-pemafibrate group and the HD-combination group compared with the HD-vehicle group. However, the expression levels did not respond significantly to pitavastatin alone. Conclusions Combination therapy with pitavastatin and pemafibrate improved lipid profiles and endothelial dysfunction in hypertension and insulin resistance model rats. Pemafibrate as an add-on strategy to statins may be useful for preventing atherosclerosis progression.
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Affiliation(s)
- Masatoki Yoshida
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Kazufumi Nakamura
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan.
| | - Toru Miyoshi
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Masashi Yoshida
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Megumi Kondo
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Kaoru Akazawa
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Tomonari Kimura
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Hiroaki Ohtsuka
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Yuko Ohno
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan.,Department of Medical Technology, Kawasaki College of Allied Health Professions, Okayama, Japan
| | - Daiji Miura
- Department of Basic and Clinical Medicine, Nagano College of Nursing, Nagano, Japan
| | - Hiroshi Ito
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
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4
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Bains W. The Role of Philanthropy in Biomedical Research: Giving Your Body and Soul. Rejuvenation Res 2019; 22:348-352. [PMID: 31298619 DOI: 10.1089/rej.2019.2222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- William Bains
- Five Alarm Bio Ltd., Hauxton, Cambridge, United Kingdom
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5
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Cedó L, Reddy ST, Mato E, Blanco-Vaca F, Escolà-Gil JC. HDL and LDL: Potential New Players in Breast Cancer Development. J Clin Med 2019; 8:jcm8060853. [PMID: 31208017 PMCID: PMC6616617 DOI: 10.3390/jcm8060853] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 06/11/2019] [Accepted: 06/12/2019] [Indexed: 02/07/2023] Open
Abstract
Breast cancer is the most prevalent cancer and primary cause of cancer-related mortality in women. The identification of risk factors can improve prevention of cancer, and obesity and hypercholesterolemia represent potentially modifiable breast cancer risk factors. In the present work, we review the progress to date in research on the potential role of the main cholesterol transporters, low-density and high-density lipoproteins (LDL and HDL), on breast cancer development. Although some studies have failed to find associations between lipoproteins and breast cancer, some large clinical studies have demonstrated a direct association between LDL cholesterol levels and breast cancer risk and an inverse association between HDL cholesterol and breast cancer risk. Research in breast cancer cells and experimental mouse models of breast cancer have demonstrated an important role for cholesterol and its transporters in breast cancer development. Instead of cholesterol, the cholesterol metabolite 27-hydroxycholesterol induces the proliferation of estrogen receptor-positive breast cancer cells and facilitates metastasis. Oxidative modification of the lipoproteins and HDL glycation activate different inflammation-related pathways, thereby enhancing cell proliferation and migration and inhibiting apoptosis. Cholesterol-lowering drugs and apolipoprotein A-I mimetics have emerged as potential therapeutic agents to prevent the deleterious effects of high cholesterol in breast cancer.
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Affiliation(s)
- Lídia Cedó
- Institut d'Investigacions Biomèdiques (IIB) Sant Pau, Sant Quintí 77, 08041 Barcelona, Spain.
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Monforte de Lemos 3-5, 28029 Madrid, Spain.
| | - Srinivasa T Reddy
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095-1736, USA.
| | - Eugènia Mato
- Institut d'Investigacions Biomèdiques (IIB) Sant Pau, Sant Quintí 77, 08041 Barcelona, Spain.
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Monforte de Lemos 3-5, 28029 Madrid, Spain.
| | - Francisco Blanco-Vaca
- Institut d'Investigacions Biomèdiques (IIB) Sant Pau, Sant Quintí 77, 08041 Barcelona, Spain.
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Monforte de Lemos 3-5, 28029 Madrid, Spain.
- Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Av. de Can Domènech 737, 08193 Cerdanyola del Vallès, Spain.
| | - Joan Carles Escolà-Gil
- Institut d'Investigacions Biomèdiques (IIB) Sant Pau, Sant Quintí 77, 08041 Barcelona, Spain.
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Monforte de Lemos 3-5, 28029 Madrid, Spain.
- Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Av. de Can Domènech 737, 08193 Cerdanyola del Vallès, Spain.
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Yamamoto T, Wada F, Harada-Shiba M. Development of Antisense Drugs for Dyslipidemia. J Atheroscler Thromb 2016; 23:1011-25. [PMID: 27466159 PMCID: PMC5090806 DOI: 10.5551/jat.rv16001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Abnormal elevation of low-density lipoprotein (LDL) and triglyceride-rich lipoproteins in plasma as well as dysfunction of anti-atherogenic high-density lipoprotein (HDL) have both been recognized as essential components of the pathogenesis of atherosclerosis and are classified as dyslipidemia. This review describes the arc of development of antisense oligonucleotides for the treatment of dyslipidemia. Chemically-armed antisense candidates can act on various kinds of transcripts, including mRNA and miRNA, via several different endogenous antisense mechanisms, and have exhibited potent systemic anti-dyslipidemic effects. Here, we present specific cutting-edge technologies have recently been brought into antisense strategies, and describe how they have improved the potency of antisense drugs in regard to pharmacokinetics and pharmacodynamics. In addition, we discuss perspectives for the use of armed antisense oligonucleotides as new clinical options for dyslipidemia, in the light of outcomes of recent clinical trials and safety concerns indicated by several clinical and preclinical studies.
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7
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Princen HMG, Pouwer MG, Pieterman EJ. Comment on "Hypercholesterolemia with consumption of PFOA-laced Western diets is dependent on strain and sex of mice" by Rebholz S.L. et al. Toxicol. Rep. 2016 (3) 46-54. Toxicol Rep 2016; 3:306-309. [PMID: 28959551 PMCID: PMC5615825 DOI: 10.1016/j.toxrep.2016.02.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 02/07/2016] [Indexed: 01/01/2023] Open
Affiliation(s)
- Hans M G Princen
- TNO-Metabolic Health Research, Gaubius Laboratory, Leiden, The Netherlands
| | - Marianne G Pouwer
- TNO-Metabolic Health Research, Gaubius Laboratory, Leiden, The Netherlands
| | - Elsbet J Pieterman
- TNO-Metabolic Health Research, Gaubius Laboratory, Leiden, The Netherlands
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8
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Sugimoto K. [New prospect of bile acid sequestrants as a novel therapy for metabolic disorders - research strategy utilizing clinical data]. Nihon Yakurigaku Zasshi 2014; 144:64-8. [PMID: 25109518 DOI: 10.1254/fpj.144.64] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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9
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dos Santos CR, Domingues G, Matias I, Matos J, Fonseca I, de Almeida JM, Dias S. LDL-cholesterol signaling induces breast cancer proliferation and invasion. Lipids Health Dis 2014; 13:16. [PMID: 24428917 PMCID: PMC3896822 DOI: 10.1186/1476-511x-13-16] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 01/10/2014] [Indexed: 01/26/2023] Open
Abstract
Lipids and cholesterol in particular, have long been associated with breast cancer (BC) onset and progression. However, the causative effects of elevated lipid levels and breast cancer remain largely undisclosed and were the subject of the present study.We took advantage of well-established in vitro and in vivo models of cholesterol enrichment to exploit the mechanism involved in LDL-cholesterol favouring BC growth and invasiveness. We analyzed its effects in models that mimic different BC subtypes and stages.Our data show that LDL-cholesterol (but not HDL-cholesterol) promotes BC cells proliferation, migration and loss of adhesion, hallmarks of the epithelial to mesenchymal transition. In vivo studies modeling cholesterol levels showed that breast tumors are consistently larger and more proliferative in hypercholesterolemic mice, which also have more frequently lung metastases. Microarray analysis revealed an over expression of intermediates of Akt and ERK pathways suggesting a survival response induced by LDL, confirmed by WB analyses. Gene expression analysis also evidenced an activation of ErbB2 signaling pathway and decreased expression of adhesion molecules (cadherin-related family member3, CD226, Claudin 7 and Ocludin) in the cells exposed to LDL.Together, the present work shows novel mechanistic evidence that high LDL-cholesterol levels promote BC progression. These data provide rationale for the clinical control of cholesterol levels in BC patients.
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Affiliation(s)
| | | | | | | | | | | | - Sérgio Dias
- Instituto Medicina Molecular, Lisbon, Portugal.
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10
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Connolly BA, O'Connell DP, Lamon-Fava S, LeBlanc DF, Kuang YL, Schaefer EJ, Coppage AL, Benedict CR, Kiritsy CP, Bachovchin WW. The high-fat high-fructose hamster as an animal model for niacin's biological activities in humans. Metabolism 2013; 62:1840-9. [PMID: 24035454 DOI: 10.1016/j.metabol.2013.08.001] [Citation(s) in RCA: 5] [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: 01/17/2013] [Revised: 07/18/2013] [Accepted: 08/03/2013] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Niacin has been used for more than 50 years to treat dyslipidemia, yet the mechanisms underlying its lipid-modifying effects remain unknown, a situation stemming at least in part from a lack of validated animal models. The objective of this study was to determine if the dyslipidemic hamster could serve as such a model. MATERIALS/METHODS Dyslipidemia was induced in Golden Syrian hamsters by feeding them a high-fat, high-cholesterol, and high-fructose (HF/HF) diet. The effect of high-dose niacin treatment for 18 days and 28 days on plasma lipid levels and gene expression was measured. RESULTS Niacin treatment produced significant decreases in plasma total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), and free fatty acids (FFA), but had no measureable effect on high-density lipoprotein cholesterol (HDL-C) in the dyslipidemic hamster. Niacin treatment also produced significant increases in hepatic adenosine ATP-Binding Cassette A1 (ABCA1) mRNA, ABCA1 protein, apolipoprotein A-I (Apo A-I) mRNA, and adipose adiponectin mRNA in these animals. CONCLUSIONS With the exception of HDL-C, the lipid effects of niacin treatment in the dyslipidemic hamster closely parallel those observed in humans. Moreover, the effects of niacin treatment on gene expression of hepatic proteins related to HDL metabolism are similar to those observed in human cells in culture. The HF/HF-fed hamster could therefore serve as an animal model for niacin's lowering of proatherogenic lipids and mechanisms of action relative to lipid metabolism.
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Affiliation(s)
- Beth A Connolly
- Tufts University Sackler School of Graduate Biomedical Sciences, Department of Biochemistry, Boston, MA, USA; Arisaph Pharmaceuticals, Boston, MA, USA
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Li ZH, Ramakrishnan S, Striepen B, Moreno SNJ. Toxoplasma gondii relies on both host and parasite isoprenoids and can be rendered sensitive to atorvastatin. PLoS Pathog 2013; 9:e1003665. [PMID: 24146616 PMCID: PMC3798403 DOI: 10.1371/journal.ppat.1003665] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Accepted: 08/14/2013] [Indexed: 01/03/2023] Open
Abstract
Intracellular pathogens have complex metabolic interactions with their host cells to ensure a steady supply of energy and anabolic building blocks for rapid growth. Here we use the obligate intracellular parasite Toxoplasma gondii to probe this interaction for isoprenoids, abundant lipidic compounds essential to many cellular processes including signaling, trafficking, energy metabolism, and protein translation. Synthesis of precursors for isoprenoids in Apicomplexa occurs in the apicoplast and is essential. To synthesize longer isoprenoids from these precursors, T. gondii expresses a bifunctional farnesyl diphosphate/geranylgeranyl diphosphate synthase (TgFPPS). In this work we construct and characterize T. gondii null mutants for this enzyme. Surprisingly, these mutants have only a mild growth phenotype and an isoprenoid composition similar to wild type parasites. However, when extracellular, the loss of the enzyme becomes phenotypically apparent. This strongly suggests that intracellular parasite salvage FPP and/or geranylgeranyl diphosphate (GGPP) from the host. We test this hypothesis using inhibitors of host cell isoprenoid synthesis. Mammals use the mevalonate pathway, which is susceptible to statins. We document strong synergy between statin treatment and pharmacological or genetic interference with the parasite isoprenoid pathway. Mice can be cured with atorvastatin (Lipitor) from a lethal infection with the TgFPPs mutant. We propose a double-hit strategy combining inhibitors of host and parasite pathways as a novel therapeutic approach against Apicomplexan parasites. Toxoplasma gondii is an obligate intracellular parasite and is not able to replicate outside the host cell. The parasite lives in a specialized parasitophorous vacuole in contact with the host cytoplasm through the parasitophorous vacuole membrane. It is highly likely that a very active exchange of metabolites occurs between parasite and host cell. We present evidence for this exchange for isoprenoids, abundant lipidic compounds essential to many cellular processes including signaling, trafficking, energy metabolism, and protein translation. Our work shows that intracellular T. gondii tachyzoites are able to salvage farnesyl diphosphate (FPP) and/or geranylgeranyl diphosphate (GGPP) from the host, and the parasite is able to grow even when its endogenous production is shut down. However, when extracellular, the parasite depends entirely on its own production of isoprenoids. We propose to use a combination of inhibitors that would hit both the host and the parasite pathways as a novel therapeutic approach against Toxoplasma gondii that could also work against other Apicomplexan parasites.
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Affiliation(s)
- Zhu-Hong Li
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Srinivasan Ramakrishnan
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Boris Striepen
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Silvia N. J. Moreno
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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12
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Parihar SP, Guler R, Lang DM, Suzuki H, Marais AD, Brombacher F. Simvastatin enhances protection against Listeria monocytogenes infection in mice by counteracting Listeria-induced phagosomal escape. PLoS One 2013; 8:e75490. [PMID: 24086542 PMCID: PMC3782446 DOI: 10.1371/journal.pone.0075490] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 08/15/2013] [Indexed: 12/16/2022] Open
Abstract
Statins are well-known cholesterol lowering drugs targeting HMG-CoA-reductase, reducing the risk of coronary disorders and hypercholesterolemia. Statins are also involved in immunomodulation, which might influence the outcome of bacterial infection. Hence, a possible effect of statin treatment on Listeriosis was explored in mice. Statin treatment prior to subsequent L. monocytogenes infection strikingly reduced bacterial burden in liver and spleen (up to 100-fold) and reduced histopathological lesions. Statin-treatment in infected macrophages resulted in increased IL-12p40 and TNF-α and up to 4-fold reduced bacterial burden within 6 hours post infection, demonstrating a direct effect of statins on limiting bacterial growth in macrophages. Bacterial uptake was normal investigated in microbeads and GFP-expressing Listeria experiments by confocal microscopy. However, intracellular membrane-bound cholesterol level was decreased, as analyzed by cholesterol-dependent filipin staining and cellular lipid extraction. Mevalonate supplementation restored statin-inhibited cholesterol biosynthesis and reverted bacterial growth in Listeria monocytogenes but not in listeriolysin O (LLO)-deficient Listeria. Together, these results suggest that statin pretreatment increases protection against L. monocytogenes infection by reducing membrane cholesterol in macrophages and thereby preventing effectivity of the cholesterol-dependent LLO-mediated phagosomal escape of bacteria.
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Affiliation(s)
- Suraj P. Parihar
- International Centre for Genetic Engineering & Biotechnology (ICGEB), Cape Town Component and Institute of Infectious Diseases and Molecular Medicine (IIDMM), Division of Immunology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Reto Guler
- International Centre for Genetic Engineering & Biotechnology (ICGEB), Cape Town Component and Institute of Infectious Diseases and Molecular Medicine (IIDMM), Division of Immunology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Dirk M. Lang
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Harukazu Suzuki
- Division of Genomic Technologies, RIKEN Center for Life Science Technologies, Yokohama, Japan
| | - A. David Marais
- Division of Chemical Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Frank Brombacher
- International Centre for Genetic Engineering & Biotechnology (ICGEB), Cape Town Component and Institute of Infectious Diseases and Molecular Medicine (IIDMM), Division of Immunology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- * E-mail:
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13
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Sugimoto-Kawabata K, Shimada H, Sakai K, Suzuki K, Kelder T, Pieterman EJ, Cohen LH, Havekes LM, Princen HM, van den Hoek AM. Colestilan decreases weight gain by enhanced NEFA incorporation in biliary lipids and fecal lipid excretion. J Lipid Res 2013; 54:1255-64. [PMID: 23434610 DOI: 10.1194/jlr.m032839] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Bile acid sequestrants (BASs) are cholesterol-lowering drugs that also affect hyperglycemia. The mechanism by which BASs exert these and other metabolic effects beyond cholesterol lowering remains poorly understood. The present study aimed to investigate the effects of a BAS, colestilan, on body weight, energy expenditure, and glucose and lipid metabolism and its mechanisms of action in high-fat-fed hyperlipidemic APOE*3 Leiden (E3L) transgenic mice. Mildly insulin-resistant E3L mice were fed a high-fat diet with or without 1.5% colestilan for 8 weeks. Colestilan treatment decreased body weight, visceral and subcutaneous fat, and plasma cholesterol and triglyceride levels but increased food intake. Blood glucose and plasma insulin levels were decreased, and hyperinsulinemic-euglycemic clamp analysis demonstrated improved insulin sensitivity, particularly in peripheral tissues. In addition, colestilan decreased energy expenditure and physical activity, whereas it increased the respiratory exchange ratio, indicating that colestilan induced carbohydrate catabolism. Moreover, kinetic analysis revealed that colestilan increased [(3)H]NEFA incorporation in biliary cholesterol and phospholipids and increased fecal lipid excretion. Gene expression analysis in liver, fat, and muscle supported the above findings. In summary, colestilan decreases weight gain and improves peripheral insulin sensitivity in high-fat-fed E3L mice by enhanced NEFA incorporation in biliary lipids and increased fecal lipid excretion.
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Affiliation(s)
- Kanami Sugimoto-Kawabata
- Metabolic Diseases, Department I, Pharmacology Research Laboratories 2, Mitsubishi Tanabe Pharma Corporation, Toda-shi, Saitama 335-8505, Japan.
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14
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Modulation of lipoprotein metabolism by antisense technology: preclinical drug discovery methodology. Methods Mol Biol 2013; 1027:309-24. [PMID: 23912993 DOI: 10.1007/978-1-60327-369-5_14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Antisense oligonucleotides (ASOs) are a new class of specific therapeutic agents that alter the intermediary metabolism of mRNA, resulting in the suppression of disease-associated gene products. ASOs exert their pharmacological effects after hybridizing, via Watson-Crick base pairing, to a specific target RNA. If appropriately designed, this event results in the recruitment of RNase H, the degradation of targeted mRNA or pre-mRNA, and subsequent inhibition of the synthesis of a specific protein. A key advantage of the technology is the ability to selectively inhibit targets that cannot be modulated by traditional therapeutics such as structural proteins, transcription factors, and, of topical interest, lipoproteins. In this chapter, we will first provide an overview of antisense technology, then more specifically describe the status of lipoprotein-related genes that have been studied using the antisense platform, and finally, outline the general methodology required to design and evaluate the in vitro and in vivo efficacy of those drugs.
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15
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Xie W, Xing D, Sun H, Wang W, Ding Y, Du L. The Effects of Ananas comosus L. Leaves on Diabetic-Dyslipidemic Rats Induced by Alloxan and a High-Fat/High-Cholesterol Diet. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2012; 33:95-105. [PMID: 15844837 DOI: 10.1142/s0192415x05002692] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The aim of this study is to demonstrate the effects of Ananas comosus L. leaves on diabetic-dyslipidemic rats. Hypoglycemic and hypolipidemic activities of the ethanolic extract of Ananas comosus L. leaves (EEACL) were evaluated in normal and alloxan-induced diabetic rats by oral glucose tolerance test and an olive oil load test. Anti-diabetic, anti-hyperlipidemic and anti-oxidative activities of EEACL were also investigated in diabetic-dyslipidemic rats induced by alloxan and a high-fat/high-cholesterol diet. EEACL at the dose of 0.40 g/kg significantly inhibited the increase in blood glucose in diabetic rats in oral glucose tolerance test, but did not cause any hypoglycerimic activity in normal rats. It also significantly inhibited the increase in postprandial triglycerides (TG) levels in both normal and diabetic rats in olive oil load test. After 15 days of treatment of diabetic dyslipidemic rats, EEACL significantly decreased blood glucose (-51.0%, P<0.01), TG (-50.1%, P<0.01), TC (-23.3%, P<0.01), LDL-c (-47.9%, P<0.01) and glycated albumin (-25.4%, P<0.01) levels, significantly increased serum high-density lipoprotein cholesterol levels (66.2%, P<0.01) and prevented lower body weight of diabetes (11.8%, P<0.05), significantly lowered lipid peroxidation productions of blood (-27.8%, P<0.01), brain (-31.6%, P<0.05), liver (-44.5%, P<0.01) and kidneys (-72.2%, P<0.05) compared with those in untreated diabetic dyslipidemic rats. These data suggest that EEACL has anti-diabetic, anti-dyslipidemic and anti-oxidative activities, which may be developed into a new plant medicine for treatment of diabetes and its complications.
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Affiliation(s)
- Weidong Xie
- Institute of Medicinal Plant, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100094, China
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16
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Yin W, Carballo-Jane E, McLaren DG, Mendoza VH, Gagen K, Geoghagen NS, McNamara LA, Gorski JN, Eiermann GJ, Petrov A, Wolff M, Tong X, Wilsie LC, Akiyama TE, Chen J, Thankappan A, Xue J, Ping X, Andrews G, Wickham LA, Gai CL, Trinh T, Kulick AA, Donnelly MJ, Voronin GO, Rosa R, Cumiskey AM, Bekkari K, Mitnaul LJ, Puig O, Chen F, Raubertas R, Wong PH, Hansen BC, Koblan KS, Roddy TP, Hubbard BK, Strack AM. Plasma lipid profiling across species for the identification of optimal animal models of human dyslipidemia. J Lipid Res 2011; 53:51-65. [PMID: 22021650 DOI: 10.1194/jlr.m019927] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In an attempt to understand the applicability of various animal models to dyslipidemia in humans and to identify improved preclinical models for target discovery and validation for dyslipidemia, we measured comprehensive plasma lipid profiles in 24 models. These included five mouse strains, six other nonprimate species, and four nonhuman primate (NHP) species, and both healthy animals and animals with metabolic disorders. Dyslipidemic humans were assessed by the same measures. Plasma lipoprotein profiles, eight major plasma lipid fractions, and FA compositions within these lipid fractions were compared both qualitatively and quantitatively across the species. Given the importance of statins in decreasing plasma low-density lipoprotein cholesterol for treatment of dyslipidemia in humans, the responses of these measures to simvastatin treatment were also assessed for each species and compared with dyslipidemic humans. NHPs, followed by dog, were the models that demonstrated closest overall match to dyslipidemic humans. For the subset of the dyslipidemic population with high plasma triglyceride levels, the data also pointed to hamster and db/db mouse as representative models for practical use in target validation. Most traditional models, including rabbit, Zucker diabetic fatty rat, and the majority of mouse models, did not demonstrate overall similarity to dyslipidemic humans in this study.
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Affiliation(s)
- Wu Yin
- Department of Atherosclerosis, Merck Research Laboratories, Rahway, NJ 07065, USA
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Lukasova M, Malaval C, Gille A, Kero J, Offermanns S. Nicotinic acid inhibits progression of atherosclerosis in mice through its receptor GPR109A expressed by immune cells. J Clin Invest 2011; 121:1163-73. [PMID: 21317532 DOI: 10.1172/jci41651] [Citation(s) in RCA: 195] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 12/15/2010] [Indexed: 12/19/2022] Open
Abstract
Nicotinic acid (niacin) is a drug used to reduce the progression of atherosclerosis. Its antiatherosclerotic activity is believed to result from lipid-modifying effects, including its ability to decrease LDL cholesterol and increase HDL cholesterol levels in plasma. Here, we report that in a mouse model of atherosclerosis, we found that nicotinic acid inhibited disease progression under conditions that left total cholesterol and HDL cholesterol plasma levels unaffected. The antiatherosclerotic effect was not seen in mice lacking the receptor for nicotinic acid GPR109A. Surprisingly, transplantation of bone marrow from GPR109A-deficient mice into atherosclerosis-prone animals also abrogated the beneficial effect of nicotinic acid. We detected expression of GPR109A in macrophages in atherosclerotic plaques. In macrophages from WT mice, but not from GPR109A-deficient animals, nicotinic acid induced expression of the cholesterol transporter ABCG1 and promoted cholesterol efflux. Furthermore, activation of GPR109A by nicotinic acid inhibited MCP-1-induced recruitment of macrophages into the peritoneal cavity and impaired macrophage recruitment to atherosclerotic plaques. In contrast with current models, our data show that nicotinic acid can reduce the progression of atherosclerosis independently of its lipid-modifying effects through the activation of GPR109A on immune cells. We conclude therefore that GPR109A mediates antiinflammatory effects, which may be useful for treating atherosclerosis and other diseases.
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Affiliation(s)
- Martina Lukasova
- Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
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18
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Modulation of HDL metabolism by the niacin receptor GPR109A in mouse hepatocytes. Biochem Pharmacol 2010; 80:1450-7. [PMID: 20655299 DOI: 10.1016/j.bcp.2010.07.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 07/07/2010] [Accepted: 07/08/2010] [Indexed: 01/13/2023]
Abstract
The niacin receptor GPR109A is a G(i)-protein-coupled receptor which mediates the effects of niacin on inhibiting intracellular triglyceride lipolysis in adipocytes. However, the role of GPR109A in mediating the effects of niacin on high density lipoprotein (HDL) metabolism is unclear. We found niacin has no effect on HDL-C in GPR109A knockout mice. Furthermore, niacin lowered intracellular cAMP in primary hepatocytes mediated by GPR109A. We used an adeno-associated viral (AAV) serotype 8 vector encoding GPR109A under the control of the hepatic-specific thyroxine-binding globulin promoter to specifically overexpress GPR109A in mouse liver. Plasma HDL-C, hepatic ABCA1 and the HDL cholesterol production rate were significantly reduced in mice overexpressing GPR109A. Overexpression of GPR109A reduced primary hepatocyte free cholesterol efflux to apoA-I; conversely, GPR109A deficient hepatocytes had increased ABCA1-mediated cholesterol efflux. These data support the concept that the HDL-C lowering effect of niacin in wild-type mice is mediated through stimulation of GPR109A in hepatocytes; such an effect then leads to reduced hepatocyte ABCA1 expression and activity, decreased cholesterol efflux to nascent apoA-I, and reduced HDL-C levels. These results indicate that niacin-mediated activation of GP109A in liver lowers ABCA1 expression leading to reduced hepatic cholesterol efflux to HDL.
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Jonker D, Kuper CF, Maquet V, Nollevaux G, Gautier S. Subchronic (13-week) oral toxicity study in rats with fungal chitin-glucan from Aspergillus niger. Food Chem Toxicol 2010; 48:2695-701. [PMID: 20600523 DOI: 10.1016/j.fct.2010.06.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 05/31/2010] [Accepted: 06/24/2010] [Indexed: 10/19/2022]
Abstract
Chitin-glucan is an insoluble biopolymer, composed of chitin and beta-(1,3)-D-glucan, that is a component of the fungal cell wall. This study was conducted to assess the safety of chitin-glucan from the mycelium of Aspergillus niger (Artinia brand) for use as dietary supplement and food ingredient. Chitin-glucan was fed to Wistar rats (20/sex/group) at dietary levels of 0, 1, 5 and 10% for 13 weeks. Clinical and neurobehavioural observations, growth, feed and water consumption, ophthalmoscopy, haematology, clinical chemistry, urinalysis, organ weights, necropsy and histopathological examination revealed no adverse effects of chitin-glucan. Rats fed chitin-glucan at 10% consumed more feed than controls, probably due to lower energy density of their diet. Water intake was increased slightly at all dose levels. These changes were not toxicologically significant. Full and empty caecum weights were increased in mid-dose males and high-dose males and females. This caecal enlargement was a physiological response to the consumption of a high amount of poorly digestible carbohydrate and considered of no toxicological concern. In conclusion, feeding chitin-glucan at dietary levels up to 10% for 13 weeks was tolerated without any signs of toxicity. This level corresponded to 6.6 and 7.0 g chitin-glucan/kg body weight/day in male and female rats, respectively.
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Affiliation(s)
- D Jonker
- TNO Quality of Life, Utrechtseweg 48, 3704 HE Zeist, The Netherlands.
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20
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Pérez-Pastén R, García RV, Garduño L, Reyes E, Labarrios F, Tamariz J, Chamorro G. Hypolipidaemic and antiplatelet activity of phenoxyacetic acid derivatives related to α-asarone. J Pharm Pharmacol 2010; 58:1343-9. [PMID: 17034657 DOI: 10.1211/jpp.58.10.0007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
The phenoxyacetic acid derivatives 1–6 [2-methoxy-4-(2-propenyl)phenoxyacetic acid (1); 2-methoxy-5-nitro-4-(2-propenyl)phenoxyacetic acid (2); methyl 2-methoxy-4-(2-propenyl)phenoxyacetate (3); ethyl 2-methoxy-4-(2-propenyl)phenoxyacetate (4); methyl 2-methoxy-5-nitro-4-(2-propenyl)phenoxyacetate (5); ethyl 2-methoxy-5-nitro-4-(2-propenyl)phenoxyacetate (6)] related to α-asarone have been reported previously as hypolipidaemic agents in diet-induced hyperlipidaemic mice. We have aimed to expand the pharmacological profile of these derivatives by investigating their hypolipidaemic activity in rats and mice under different experimental conditions. The antiplatelet activity was tested also in-vitro from blood derived from consenting healthy volunteers. In normolipidaemic rats, compounds 2, 3 and 5 at oral doses of 40 and 80 mg kg−1 significantly decreased total cholesterol and LDL-cholesterol levels. Moreover, analogues 3 and 5 administered to hypercholesterolaemic rats at the same doses for seven days also produced a reduction in the content of these same lipoproteins. In neither case were the high-density lipoprotein cholesterol and triglyceride concentrations affected. However, practically all tested compounds were found to be hypocholesterolaemic agents, and were shown to effectively lower low-density lipoprotein cholesterol and triglyceride levels in Triton-induced hyperlipidaemic mice at oral doses of 50 and 100 mg kg−1. In all tests, all animals appeared to be healthy throughout the experimental period in their therapeutic ranges. Triton-induced hypercholesterolaemic mice appeared to be a desirable model for this class of hypolipidaemic drugs. On the other hand, compounds 1, 2, 4 and 5 significantly inhibited ADP-induced aggregation in-vitro. These findings indicated that all of these compounds appeared to be promising for the treatment of human hyperlipidaemia and thrombotic diseases.
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Affiliation(s)
- Ricardo Pérez-Pastén
- Area Académica de Farmacia, Instituto de Ciencias de la Salud, Universidad Autónoma del Estado de Hidalgo, México
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21
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Xiong Q, Lin M, Rikihisa Y. Cholesterol-dependent anaplasma phagocytophilum exploits the low-density lipoprotein uptake pathway. PLoS Pathog 2009; 5:e1000329. [PMID: 19283084 PMCID: PMC2654415 DOI: 10.1371/journal.ppat.1000329] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Accepted: 02/05/2009] [Indexed: 11/18/2022] Open
Abstract
In eukaryotes, intracellular cholesterol homeostasis and trafficking are tightly regulated. Certain bacteria, such as Anaplasma phagocytophilum, also require cholesterol; it is unknown, however, how this cholesterol-dependent obligatory intracellular bacterium of granulocytes interacts with the host cell cholesterol regulatory pathway to acquire cholesterol. Here, we report that total host cell cholesterol increased >2-fold during A. phagocytophilum infection in a human promyelocytic leukemia cell line. Cellular free cholesterol was enriched in A. phagocytophilum inclusions as detected by filipin staining. We determined that A. phagocytophilum requires cholesterol derived from low-density lipoprotein (LDL), because its replication was significantly inhibited by depleting the growth medium of cholesterol-containing lipoproteins, by blocking LDL uptake with a monoclonal antibody against LDL receptor (LDLR), or by treating the host cells with inhibitors that block LDL-derived cholesterol egress from late endosomes or lysosomes. However, de novo cholesterol biosynthesis is not required, since inhibition of the biosynthesis pathway did not inhibit A. phagocytophilum infection. The uptake of fluorescence-labeled LDL was enhanced in infected cells, and LDLR expression was up-regulated at both the mRNA and protein levels. A. phagocytophilum infection stabilized LDLR mRNA through the 3′ UTR region, but not through activation of the sterol regulatory element binding proteins. Extracellular signal–regulated kinase (ERK) was up-regulated by A. phagocytophilum infection, and inhibition of its upstream kinase, MEK, by a specific inhibitor or siRNA knockdown, reduced A. phagocytophilum infection. Up-regulation of LDLR mRNA by A. phagocytophilum was also inhibited by the MEK inhibitor; however, it was unclear whether ERK activation is required for LDLR mRNA up-regulation by A. phagocytophilum. These data reveal that A. phagocytophilum exploits the host LDL uptake pathway and LDLR mRNA regulatory system to accumulate cholesterol in inclusions to facilitate its replication. Maintenance of the cholesterol amount and transport within cells are essential for healthy human cell functions. Most bacteria do not need cholesterol, but certain bacteria that infect human cells are dependent on host cell cholesterol for their infection. How infected human cells deal with these cholesterol-robbing bacteria, and in turn how these bacteria hijack host cholesterol, are intriguing questions. Anaplasma phagocytophilum is a bacterium that lives inside white blood cells, and causes the disease human granulocytic anaplasmosis (HGA). A. phagocytophilum needs host cholesterol to live. Here, we discovered that A. phagocytophilum infection increases the amount of cholesterol in host cells and sequesters the majority of cholesterol in A. phagocytophilum inclusions inside host cells. Human cells acquire cholesterol from two sources: receptor-mediated endocytosis of cholesterol-containing low-density lipoprotein (LDL) from the circulating blood, and synthesis of cholesterol inside the cells. Since A. phagocytophilum depends on cholesterol derived from LDL, it coaxes the host cell to take up more LDL by increasing LDL receptor, through inhibition of LDL receptor mRNA degradation. A. phagocytophilum infection may serve as a model to improve our understanding of the cellular cholesterol regulation in white blood cells, and may provide insight regarding new therapeutic target for treatment of HGA.
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Affiliation(s)
- Qingming Xiong
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, United States of America
| | - Mingqun Lin
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, United States of America
| | - Yasuko Rikihisa
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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PAR-5359, a well-balanced PPARalpha/gamma dual agonist, exhibits equivalent antidiabetic and hypolipidemic activities in vitro and in vivo. Eur J Pharmacol 2008; 595:119-25. [PMID: 18727927 DOI: 10.1016/j.ejphar.2008.07.066] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 07/16/2008] [Accepted: 07/23/2008] [Indexed: 02/01/2023]
Abstract
Peroxisome proliferator-activated receptor (PPAR) alpha and gamma are key regulators of lipid homeostasis and insulin resistance. In this study, we characterize the pharmacological profiles of PAR-5359, a dual agonist of PPARalpha and gamma with well-balanced activities. In transient transactivation assay, PAR-5359 (3-(4-(2[4-(4chloro-phenyl)-3,6-dihydro-2H-pyridin-1-yl]-ethoxy)-phenyl)-(2S)-ethoxy-propionic acid) significantly activated human and mouse PPARalpha and gamma without activating PPARdelta. In functional assays using human mesenchymal stem cells and human hepatoma HepG2 cells, PAR-5359 significantly induced adipocyte differentiation and human ApoA1 secretion, which coincided with its transactivation potencies against the corresponding human receptor subtypes. Interestingly, PAR-5359 showed equivalent potencies against the mouse receptor subtypes (alpha and gamma; 2.84 microM and 3.02 microM, respectively), which suggests the possibility that PAR-5359 could simultaneously activates each subtype of receptors subtype in under physiological conditions. In an insulin-resistant ob/ob mouse model, PAR-5359 significantly reduced plasma insulin levels, improved insulin sensitivity (HOMA-IR), and completely normalized plasma glucose levels. In a severe diabetic db/db mouse model, PAR-5359 dose-dependently reduced the plasma levels of glucose (ED(30) = 0.07 mg/kg). Furthermore, it lowered plasma levels of non HDL- (ED(30) = 0.13 mg/kg) and total cholesterol (ED(30) = 0.03 mg/kg) in high cholesterol diet-fed rats for 4 days treatment. These results suggest that PAR-5359 has the balanced activities for PPARalpha and PPARgamma in vivo as well as in vitro. And its balanced activities may render PAR-5359 as a pharmacological tool in elucidating the complex roles of PPARalpha/gamma dual agonists.
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van der Hoorn JWA, de Haan W, Berbée JFP, Havekes LM, Jukema JW, Rensen PCN, Princen HMG. Niacin increases HDL by reducing hepatic expression and plasma levels of cholesteryl ester transfer protein in APOE*3Leiden.CETP mice. Arterioscler Thromb Vasc Biol 2008; 28:2016-22. [PMID: 18669886 DOI: 10.1161/atvbaha.108.171363] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
OBJECTIVE Niacin potently decreases plasma triglycerides and LDL-cholesterol. In addition, niacin is the most potent HDL-cholesterol-increasing drug used in the clinic. In the present study, we aimed at elucidation of the mechanism underlying its HDL-raising effect. METHODS AND RESULTS In APOE*3Leiden transgenic mice expressing the human CETP transgene, niacin dose-dependently decreased plasma triglycerides (up to -77%, P<0.001) and total cholesterol (up to -66%, P<0.001). Concomitantly, niacin dose-dependently increased HDL-cholesterol (up to +87%, P<0.001), plasma apoAI (up to +72%, P<0.001), as well as the HDL particle size. In contrast, in APOE*3Leiden mice, not expressing CETP, niacin also decreased total cholesterol and triglycerides but did not increase HDL-cholesterol. In fact, in APOE*3Leiden.CETP mice, niacin dose-dependently decreased the hepatic expression of CETP (up to -88%; P<0.01) as well as plasma CETP mass (up to -45%, P<0.001) and CETP activity (up to -52%, P<0.001). Additionally, niacin dose-dependently decreased the clearance of apoAI from plasma and reduced the uptake of apoAI by the kidneys (up to -90%, P<0.01). CONCLUSIONS Niacin markedly increases HDL-cholesterol in APOE*3Leiden.CETP mice by reducing CETP activity, as related to lower hepatic CETP expression and a reduced plasma (V)LDL pool, and increases HDL-apoAI by decreasing the clearance of apoAI from plasma.
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Affiliation(s)
- José W A van der Hoorn
- Netherlands Organization for Applied Scientific Research-Quality of Life, Gaubius Laboratory, Leiden, The Netherlands.
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Mikael LG, Rozen R. Homocysteine modulates the effect of simvastatin on expression of ApoA-I and NF-kappaB/iNOS. Cardiovasc Res 2008; 80:151-8. [PMID: 18540024 DOI: 10.1093/cvr/cvn157] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
AIMS Statins can ameliorate atherosclerosis by inhibition of cholesterol biosynthesis or by modulation of inflammation. In earlier work, we showed that homocysteine (Hcy) reduced synthesis of apolipoprotein A-I (ApoA-I). Our goal in this study was to determine whether Hcy could interfere with the ability of simvastatin to increase ApoA-I synthesis or to modify statin-dependent regulation of inflammatory factors. METHODS AND RESULTS Human HepG2 hepatocarcinoma cells and murine RAW264.7 macrophages were treated with simvastatin, with and without Hcy, to examine the expression of ApoA-I and nuclear factor-kappaB (NF-kappaB) or the NF-kappaB target, inducible nitric-oxide synthase (iNOS), respectively. Mice with methylenetetrahydrofolate reductase (Mthfr) deficiency, an animal model of hyperhomocysteinemia, were administered simvastatin (in diets or by injection) for in vivo assessment of these interactions. In HepG2 cells, Hcy reduced the statin-dependent increases in ApoA-I protein, mRNA, and ApoA-I promoter activity. In RAW264.7 macrophages, simvastatin decreased, whereas Hcy increased, the expression of pro-inflammatory NF-kappaB protein; in the presence of both Hcy and simvastatin, the pro-inflammatory effect of Hcy prevailed. Hcy increased mRNA levels of iNOS in the macrophage line; the combination of Hcy and simvastatin resulted in a trend towards greater induction. In mouse studies, simvastatin decreased cholesterol levels, but levels of ApoA-I in Mthfr-deficient mice remained lower than those in Mthfr(+/+) mice. Simvastatin injection increased iNOS protein and mRNA levels in peripheral blood of hyperhomocysteinemic Mthfr-deficient mice, but not in Mthfr(+/+) mice. The drug also increased MTHFR protein in cells and mouse liver, an effect that was modified by Hcy. CONCLUSION These findings provide a link between statins and folate-dependent Hcy metabolism, and suggest that Hcy interferes with some anti-atherogenic and anti-inflammatory properties of simvastatin. Our work may have clinical relevance for hyperhomocysteinemic individuals on statin therapy.
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Affiliation(s)
- Leonie G Mikael
- Department of Human Genetics, McGill University, Montreal Children's Hospital Research Institute, 4060 Ste. Catherine West, Suite 241, Montréal, Quebec, Canada H3Z 2Z3
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Influence of sodium monoketocholate on the hypolipidemic activity of lovastatin in healthy and diabetic rats. Eur J Drug Metab Pharmacokinet 2008; 33:77-84. [DOI: 10.1007/bf03191024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Abstract
The dramatic failure of clinical trials evaluating the cholesterol ester transfer protein inhibitor torcetrapib has led to considerable doubt about the value of raising high-density lipoprotein cholesterol (HDL-C) as a treatment for cardiovascular disease. These results have underscored the intricacy of HDL metabolism, with functional quality perhaps being a more important consideration than the circulating quantity of HDL. As a result, HDL-based therapeutics that maintain or enhance HDL functionality warrant closer investigation. In this article, we review the complexity of HDL metabolism, discuss clinical-trial data for HDL-raising agents, including possible reasons for the failure of torcetrapib, and consider the potential for future HDL-based therapies.
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Jozefowicz E, Brisson H, Rozenberg S, Mebazaa A, Gelé P, Callebert J, Lebuffe G, Vallet B, Bordet R, Tavernier B. Activation of peroxisome proliferator-activated receptor-alpha by fenofibrate prevents myocardial dysfunction during endotoxemia in rats. Crit Care Med 2007; 35:856-63. [PMID: 17255874 DOI: 10.1097/01.ccm.0000256843.75446.a0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To investigate the effects of fenofibrate, an activator of peroxisome proliferator-activated receptor-alpha, on cardiac function in a rat endotoxemia model. DESIGN Prospective, randomized, controlled study. SETTING University research laboratory. SUBJECTS Three-month-old male Wistar rats. INTERVENTIONS Animals were fed with standard diet containing no drug or fenofibrate (0.2%) for 14 days. They were then injected intravenously with either 5 mg/kg lipopolysaccharide (LPS and fenofibrate + LPS groups) or saline (control and fenofibrate groups). MEASUREMENTS AND MAIN RESULTS In the LPS group, body weight loss, metabolic acidosis, and thrombocytopenia confirmed presence of systemic endotoxemia. LPS administration resulted in an early peak in plasma tumor necrosis factor-alpha, decreased cardiac contractility (isolated and perfused heart), reduced myofilament Ca2+ sensitivity (Triton-skinned cardiac fibers), and increased left ventricular nitric oxide (NO) end-oxidation products (NO(x) and NO2), without evidence of myocardial oxidative stress (thiobarbituric acid-reactive substances and antioxidant enzyme activities). Fenofibrate pretreatment (fenofibrate + LPS group) did not alter signs of endotoxemia but prevented reductions in both cardiac contractility and myofilament Ca2+ sensitivity. The peak of plasma tumor necrosis factor-alpha was attenuated, whereas myocardial NO(x) and NO2 remained similar to the LPS group. Oxidative stress was suggested from moderate increase in cardiac thiobarbituric acid-reactive substances and reduced glutathione peroxidase activity. CONCLUSION Fenofibrate, an activator of peroxisome proliferator-activated receptor-alpha, may prevent endotoxemia-induced cardiac dysfunction and reduction in myofilament Ca2+ sensitivity. Our data also suggest a mediating role for early peak plasma tumor necrosis factor-alpha, but not for myocardial NO production or oxidative stress.
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Affiliation(s)
- Elsa Jozefowicz
- Laboratoire de Pharmacologie, Faculté de Médecine, Université Lille II, Lille, France
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Hernandez M, Wright SD, Cai TQ. Critical role of cholesterol ester transfer protein in nicotinic acid-mediated HDL elevation in mice. Biochem Biophys Res Commun 2007; 355:1075-80. [PMID: 17335774 DOI: 10.1016/j.bbrc.2007.02.079] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Accepted: 02/15/2007] [Indexed: 11/26/2022]
Abstract
Nicotinic acid is a commonly used anti-dyslipidemic agent that increases plasma levels of HDL-cholesterol and decrease triglycerides (TG), and VLDL- and LDL-cholesterol. The most well-studied effect of nicotinic acid is its ability to lower plasma free fatty acids, which has been observed in humans and many animal models. However, its ability to raise HDL in humans has not been replicated in animal models, which precludes studying the mechanism of HDL elevation. Here we studied lipid-modulating effects of nicotinic acid in mice carrying genomic DNA fragments that drive expression of various human genes in the mouse liver. Treatment with nicotinic acid reduced serum levels of HDL cholesterol in wild-type and human apolipoprotein B100 (apoB100)-transgenic mice. In contrast, nicotinic acid treatment of mice that express human cholesteryl ester transfer protein (CETP), with or without concomitant apoB100 expression, resulted in a significant increase of HDL cholesterol and reduction of TG, VLDL- and LDL-cholesterol. These data demonstrate a critical role of CETP in nicotinic acid-mediated HDL elevation, and suggest that mice carrying the human CETP gene may be useful animal models for studying the HDL-elevating effect of nicotinic acid.
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Affiliation(s)
- Melba Hernandez
- Department of Cardiovascular Diseases, Merck Research Laboratories, RY80L-126, 126 East Lincoln Avenue, Rahway, NJ 07065, USA
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Srinath Reddy K, Katan MB. Diet, nutrition and the prevention of hypertension and cardiovascular diseases. Public Health Nutr 2007; 7:167-86. [PMID: 14972059 DOI: 10.1079/phn2003587] [Citation(s) in RCA: 286] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
AbstractCardiovascular diseases (CVD) are growing contributors to global disease burdens, with epidemics of CVD advancing across many regions of the world which are experiencing a rapid health transition. Diet and nutrition have been extensively investigated as risk factors for major cardiovascular diseases like coronary heart disease (CHD) and stroke and are also linked to other cardiovascular risk factors like diabetes, high blood pressure and obesity. The interpretation of evidence needs to involve a critical appraisal of methodological issues related to measurement of exposures, nature of outcome variables, types of research design and careful separation of cause, consequence and confounding as the basis for observed associations.Adequate evidence is available, from studies conducted within and across populations, to link several nutrients, minerals, food groups and dietary patterns with an increased or decreased risk of CVD. Dietary fats associated with an increased risk of CHD include trans–fats and saturated fats, while polyunsaturated fats are known to be protective. Dietary sodium is associated with elevation of blood pressure, while dietary potassium lowers the risk of hypertension and stroke. Regular frequent intake of fruits and vegetables is protective against hypertension, CHD and stroke. Composite diets (such as DASH diets, Mediterranean diet, ‘prudent’ diet) have been demonstrated to reduce the risk of hypertension and CHD. Sufficient knowledge exists to recommend nutritional interventions, at both population and individual levels, to reduce cardiovascular risk. That knowledge should now be translated into policies which promote healthy diets and discourage unhealthy diets. This requires coordinated action at the level of governments, international organizations, civil society and responsible sections of the food industry.
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Affiliation(s)
- K Srinath Reddy
- Department of Cardiology, Cardiothoracic Centre, All India Institute of Medical Sciences, New Delhi, India.
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31
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Suckling K. The ideal model in atherosclerosis and dyslipidaemia – does it exist? Expert Opin Drug Discov 2006; 1:507-11. [DOI: 10.1517/17460441.1.6.507] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Keith Suckling
- 291 Knightsfield, Welwyn Garden City, Hertfordshire, AL8 7NH, UK
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Tang LQ, Wei W, Chen LM, Liu S. Effects of berberine on diabetes induced by alloxan and a high-fat/high-cholesterol diet in rats. JOURNAL OF ETHNOPHARMACOLOGY 2006; 108:109-15. [PMID: 16759828 DOI: 10.1016/j.jep.2006.04.019] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2005] [Revised: 04/18/2006] [Accepted: 04/23/2006] [Indexed: 05/10/2023]
Abstract
Berberine is the major active constituent of Rhizoma coptidis. The present study was carried out to investigate the effect of berberine on diabetes in rats and its possible mechanisms. Diabetes was induced by tail vein injection with alloxan in Wistar rats. The amount of alloxan administered was 55 mg/kg. Diabetic rats were fed with a high-cholesterol diet. The fasting blood glucose, total cholesterol (TC), triglyceride (TG) and low density lipoprotein-cholesterol (LDL-c), high density lipoprotein-cholesterol (HDL-c), nitric oxide (NO) levels in serum and malondialdehyde (MDA),superoxide dismutase (SOD),glutathione peroxidase (GSH-px) contents in heart tissue were assayed by spectrophotometry. Pancreas samples collected after 3 weeks of alloxan treatment were stained with hematoxylin-eosin (HE) and examined under a light microscope, and scored. Intragastric administration of berberine (100 and 200 mg/kg) significantly decreased fasting blood glucose levels, serum content of TC, TG, LDL-c, and effectively increased HDL-c, NO level in diabetic rats. Furthermore, berberine treatment significantly blocked the increase of MDA, increased SOD and GSH-px levels in diabetic rats. Histopathological scores showed that berberine had restored the damage of pancreas tissues in rats with diabetes mellitus. The results showed berberine significantly inhibited the progression of diabetes induced by alloxan, and the inhibitory effect of berberine on diabetes might be associated with its hypoglycemic effect, modulating lipids metabolic effects and its ability to scavenge free radical.
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Affiliation(s)
- Li-Qin Tang
- Institute of Clinical Pharmacology, Key Laboratory of Chinese Medicine Research and Development, Anhui Medical University, Anhui Province, Hefei 230032, PR China
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Abeles AM, Pillinger MH. Statins as antiinflammatory and immunomodulatory agents: A future in rheumatologic therapy? ACTA ACUST UNITED AC 2006; 54:393-407. [PMID: 16447216 DOI: 10.1002/art.21521] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Aryeh M Abeles
- New York University School of Medicine, the Hospital for Joint Diseases, New York, New York, USA
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Duncan RE, El-Sohemy A, Archer MC. Statins and cancer development. Cancer Epidemiol Biomarkers Prev 2005; 14:1897-8. [PMID: 16103434 DOI: 10.1158/1055-9965.epi-05-0027] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
There is epidemiologic evidence that the hydrophilic 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase inhibitor pravastatin increases the incidence of some extrahepatic cancers, although this finding has been attributed to chance. We hypothesize that pravastatin is able to promote the development of cancer by causing an induction of HMG-CoA reductase and, hence, mevalonate synthesis in extrahepatic tissues. We have shown that mevalonate, the product of HMG-CoA reductase, promotes the growth of breast cancer cells. Because there is no uptake of pravastatin by most extrahepatic cells, this statin will be unable to mitigate the increase in mevalonate synthesis in extrahepatic tissues that accompanies the decrease in circulating cholesterol caused by its inhibition of hepatic HMG-CoA reductase.
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Affiliation(s)
- Robin E Duncan
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College Street, Toronto, ON, Canada M5S 3E2
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35
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Kalinichev M, Rourke C, Daniels AJ, Grizzle MK, Britt CS, Ignar DM, Jones DNC. Characterisation of olanzapine-induced weight gain and effect of aripiprazole vs olanzapine on body weight and prolactin secretion in female rats. Psychopharmacology (Berl) 2005; 182:220-31. [PMID: 16001110 DOI: 10.1007/s00213-005-0081-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2005] [Accepted: 05/19/2005] [Indexed: 10/25/2022]
Abstract
RATIONALE Atypical antipsychotic drug (APD)-induced weight gain causes non-compliance, increasing the risk of relapse and medical complications. OBJECTIVES In an animal model, we assessed body weights, food intake, body fat/lean body mass contents and blood serum levels of glucose and lipids in female rats treated with olanzapine (Experiment 1). Also, we investigated the effect of aripiprazole vs olanzapine treatment on weight gain (WG) and plasma prolactin secretion in two strains (Wistar and Sprague-Dawley) and in two housing conditions (singly and group housed; Experiment 2). METHODS In Experiment 1, Wistar females received either vehicle or olanzapine (5.0 mg kg(-1), p.o.) twice daily for 14 days. In Experiment 2, female rats (Wistar or Sprague-Dawley), housed singly or in groups, received either vehicle, aripiprazole (2.0-8.0 mg kg(-1), p.o.), or olanzapine (1.0-10 mg kg(-1), p.o.) twice daily for 7 days. Body weights and food intake were assessed daily. Body composition and blood assays were analyzed at the end of the treatment. RESULTS WG induced by chronic olanzapine treatment was characterised by hyperphagia, increased body fat, and serum free fatty acid content and reduced lean tissue and serum glucose content. Subchronic aripiprazole treatment resulted in rapid and robust WG similar to those observed with olanzapine. In spite of similar effects on body weight, aripiprazole and olanzapine stimulated markedly different patterns of prolactin secretion. Body weight changes and prolactin secretion induced by these APDs were significantly modulated by housing and by strain. CONCLUSION Assessment of body weight in the present model may not have predictive validity, and other measures may be needed to differentiate between WG-inducing and weight-neutral drugs.
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Affiliation(s)
- Mikhail Kalinichev
- Schizophrenia and Bipolar Disorders-In vivo Biology, Psychiatry CEDD, GlaxoSmithKline PLC, Harlow, Essex, CM19 5AW, UK.
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Crooke RM, Graham MJ, Lemonidis KM, Whipple CP, Koo S, Perera RJ. An apolipoprotein B antisense oligonucleotide lowers LDL cholesterol in hyperlipidemic mice without causing hepatic steatosis. J Lipid Res 2005; 46:872-84. [PMID: 15716585 DOI: 10.1194/jlr.m400492-jlr200] [Citation(s) in RCA: 187] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
High levels of plasma apolipoprotein B-100 (apoB-100), the principal apolipoprotein of LDL, are associated with cardiovascular disease. We hypothesized that suppression of apoB-100 mRNA by an antisense oligonucleotide (ASO) would reduce LDL cholesterol (LDL-C). Because most of the plasma apoB is made in the liver, and antisense drugs distribute to that organ, we tested the effects of a mouse-specific apoB-100 ASO in several mouse models of hyperlipidemia, including C57BL/6 mice fed a high-fat diet, Apoe-deficient mice, and Ldlr-deficient mice. The lead apoB-100 antisense compound, ISIS 147764, reduced apoB-100 mRNA levels in the liver and serum apoB-100 levels in a dose- and time-dependent manner. Consistent with those findings, total cholesterol and LDL-C decreased by 25-55% and 40-88%, respectively. Unlike small-molecule inhibitors of microsomal triglyceride transfer protein, ISIS 147764 did not produce hepatic or intestinal steatosis and did not affect dietary fat absorption or elevate plasma transaminase levels. These findings, as well as those derived from interim phase I data with a human apoB-100 antisense drug, suggest that antisense inhibition of this target may be a safe and effective approach for the treatment of humans with hyperlipidemia.
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Affiliation(s)
- Rosanne M Crooke
- Cardiovascular Group, Antisense Drug Discovery, Isis Pharmaceuticals, Inc., 2292 Faraday Avenue, Carlsbad, CA 92008, USA.
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37
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Delsing DJM, Post SM, Groenendijk M, Solaas K, van der Boom H, van Duyvenvoorde W, de Wit ECM, Bloks VW, Kuipers F, Havekes LM, Princen HMG. Rosuvastatin Reduces Plasma Lipids by Inhibiting VLDL Production and Enhancing Hepatobiliary Lipid Excretion in ApoE*3-Leiden Mice. J Cardiovasc Pharmacol 2005; 45:53-60. [PMID: 15613980 DOI: 10.1097/00005344-200501000-00010] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The present study was designed to investigate the lipid-lowering properties and mechanisms of action of a new HMG-CoA reductase inhibitor, rosuvastatin, in female ApoE*3-Leiden transgenic mice. Mice received a high fat/cholesterol (HFC) diet containing either rosuvastatin (0 [control], 0.00125%, 0.0025%, or 0.005% [w/w]) or 0.05% (w/w) lovastatin. The highest dose of rosuvastatin reduced plasma cholesterol and triglyceride levels by 39% and 42%, respectively, compared with the HFC control. Lovastatin had no effect on plasma cholesterol and triglyceride levels. In ApoE*3-Leiden mice on a chow diet, rosuvastatin (0.005% [w/w]) decreased plasma cholesterol levels by 35% without having an effect on triglyceride levels. On a chow diet, expression of genes involved in cholesterol biosynthesis and uptake in the liver was increased by rosuvastatin. Further mechanistic studies in HFC-fed mice showed that rosuvastatin treatment resulted in decreased hepatic VLDL-triglyceride and VLDL-apolipoprotein B production. VLDL lipid composition remained unchanged, indicating a reduction in the number of VLDL particles secreted. Lipolytic activity and expression of genes involved in cholesterol and triglyceride synthesis and beta-oxidation of fatty acids in the liver were not affected by rosuvastatin treatment, and hepatic lipid content did not change. However, activity of hepatic diacylglycerol acyltransferase was significantly decreased by 25% after rosuvastatin treatment. Moreover, biliary excretion of cholesterol, phospholipids, and bile acids was increased during treatment. The results indicate that rosuvastatin treatment in ApoE*3-Leiden mice on a HFC diet leads to redistribution of cholesterol and triglycerides in the body, both by reduced hepatic VLDL production and triglyceride synthesis and by enhanced hepatobiliary removal of cholesterol, bile acids, and phospholipids, resulting in substantial reductions in plasma cholesterol and triglyceride levels.
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Levin N, Bischoff ED, Daige CL, Thomas D, Vu CT, Heyman RA, Tangirala RK, Schulman IG. Macrophage Liver X Receptor Is Required for Antiatherogenic Activity of LXR Agonists. Arterioscler Thromb Vasc Biol 2005; 25:135-42. [PMID: 15539622 DOI: 10.1161/01.atv.0000150044.84012.68] [Citation(s) in RCA: 193] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective—
Complications of atherosclerotic cardiovascular disease due to elevated blood cholesterol levels are the major cause of death in the Western world. The liver X receptors, LXRα and LXRβ (LXRs), are ligand-dependent transcription factors that act as cholesterol sensors and coordinately control transcription of genes involved in cholesterol and lipid homeostasis as well as macrophage inflammatory gene expression. LXRs regulate cholesterol balance through activation of ATP-binding cassette transporters that promote cholesterol transport and excretion from the liver, intestine, and macrophage. Although LXR agonists are known to delay progression of atherosclerosis in mouse models, their ability to abrogate preexisting cardiovascular disease by inducing regression and stabilization of established atherosclerotic lesions has not been addressed.
Methods and Results—
We demonstrate that LXR agonist treatment increases ATP-binding cassette transporter expression within preexisting atherosclerotic lesions, resulting in regression of these lesions as well as remodeling from vulnerable to stable lesions and a reduction in macrophage content. Further, using macrophage-selective LXR-deficient mice created by bone marrow transplantation, we provide the first evidence that macrophage LXR expression is necessary for the atheroprotective actions of an LXR agonist.
Conclusions—
These data substantiate that drugs targeting macrophage LXR activity may offer therapeutic benefit in the treatment of atherosclerotic cardiovascular disease.
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Affiliation(s)
- Nancy Levin
- X-Ceptor Therapeutics Inc, San Diego, Calif 92121, USA
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Frederiksen KS, Wulff EM, Sauerberg P, Mogensen JP, Jeppesen L, Fleckner J. Prediction of PPAR-alpha ligand-mediated physiological changes using gene expression profiles. J Lipid Res 2004; 45:592-601. [PMID: 14999041 DOI: 10.1194/jlr.m300239-jlr200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Peroxisome proliferator-activated receptor (PPAR)-alpha controls the transcription of a variety of genes involved in lipid metabolism and is the target receptor for the hypolipidemic drug class of fibrates. In the present study, the molecular and physiological effects of seven different PPAR-activating drugs have been examined in a rodent model of dyslipidemia. The drugs examined were selected to display varying potencies and efficacies toward PPAR-alpha. To help elucidate the link between the gene regulation elicited by PPAR-alpha ligands and the concomitant physiological changes, we have used cDNA microarray analysis to identify smaller gene sets that are predictive of the function of these ligands. A number of genes showed strong correlations to the relative PPAR-alpha efficacy of the drugs. Furthermore, using multivariate analysis, a strong relationship between the drug-induced triglyceride lowering and the transcriptional profiles of the different drugs could be found.
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Duncan RE, El-Sohemy A, Archer MC. Mevalonate promotes the growth of tumors derived from human cancer cells in vivo and stimulates proliferation in vitro with enhanced cyclin-dependent kinase-2 activity. J Biol Chem 2004; 279:33079-84. [PMID: 15155733 DOI: 10.1074/jbc.m400732200] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Malignant cells are known to have elevated rates of mevalonate synthesis because of increased levels and catalytic efficiency of 3-hydroxy-3-methylglutaryl-CoA reductase. Whether this increased mevalonate synthesis occurs as a consequence of increased requirements for a mevalonate-derived metabolite in response to rapid growth or whether mevalonate promotes the growth of tumor cells is unknown. To address this question, we administered mevalonate via miniosmotic pumps to nude mice inoculated with MDA-MB-435 human cancer cells. After 13 weeks of growth, tumors in mevalonate-treated mice were significantly larger than tumors in saline-treated, control mice (1.52 +/- 0.26 g versus 0.81 +/- 0.27 g respectively, p < 0.05). The cancer cells treated in culture with mevalonate also demonstrated increased proliferation rates associated with accelerated entry of cells into S phase. These cells had enhanced total and cyclin A-immunoprecipitable cyclin-dependent kinase-2 (CDK-2) activity, increased activating phosphorylation of CDK-2, and decreased inhibitory binding of CDK-2 to p21(Cip1). Our findings demonstrate that mevalonate promotes tumor growth and suggest that an increase in mevalonate synthesis in extrahepatic tissues following cholesterol-lowering therapy may explain the elevated risk of cancer shown in some studies.
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Affiliation(s)
- Robin E Duncan
- Departments of Nutritional Sciences and Medical Biophysics, University of Toronto, Toronto, Ontario M5S 3E2, Canada
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Fu T, Mukhopadhyay D, Davidson NO, Borensztajn J. The peroxisome proliferator-activated receptor alpha (PPARalpha) agonist ciprofibrate inhibits apolipoprotein B mRNA editing in low density lipoprotein receptor-deficient mice: effects on plasma lipoproteins and the development of atherosclerotic lesions. J Biol Chem 2004; 279:28662-9. [PMID: 15123680 DOI: 10.1074/jbc.m403271200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Low density lipoprotein receptor (LDLR)-deficient mice fed a chow diet have a mild hypercholesterolemia caused by the abnormal accumulation in the plasma of apolipoprotein B (apoB)-100- and apoB-48-carrying intermediate density lipoproteins (IDL) and low density lipoproteins (LDL). Treatment of LDLR-deficient mice with ciprofibrate caused a marked decrease in plasma apoB-48-carrying IDL and LDL but at the same time caused a large accumulation of triglyceride-depleted apoB-100-carrying IDL and LDL, resulting in a significant increase in plasma cholesterol levels. These plasma lipoprotein changes were associated with an increase in the hepatic secretion of apoB-100-carrying very low density lipoproteins (VLDL) and a decrease in the secretion of apoB-48-carrying VLDL, accompanied by a significant decrease in hepatic apoB mRNA editing. Hepatic apobec-1 complementation factor mRNA and protein abundance were significantly decreased, whereas apobec-1 mRNA and protein abundance remained unchanged. No changes in apoB mRNA editing occurred in the intestine of the treated animals. After 150 days of treatment with ciprofibrate, consistent with the increased plasma accumulation of apoB-100-carrying IDL and LDL, the LDLR-deficient mice displayed severe atherosclerotic lesions in the aorta. These findings demonstrate that ciprofibrate treatment decreases hepatic apoB mRNA editing and alters the pattern of hepatic lipoprotein secretion toward apoB-100-associated VLDL, changes that in turn lead to increased atherosclerosis.
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Affiliation(s)
- Tao Fu
- Department of Pathology, Northwestern University Feinberg School of Medicine, 303 E Chicago Avenue, Chicago, IL 60611, USA
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Catron DM, Lange Y, Borensztajn J, Sylvester MD, Jones BD, Haldar K. Salmonella enterica serovar Typhimurium requires nonsterol precursors of the cholesterol biosynthetic pathway for intracellular proliferation. Infect Immun 2004; 72:1036-42. [PMID: 14742551 PMCID: PMC321618 DOI: 10.1128/iai.72.2.1036-1042.2004] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
We have previously shown that Salmonella enterica serovar Typhimurium infection perturbs the host cholesterol biosynthetic pathway. Here we show that inhibiting the first step of this pathway (3-hydroxy-3-methylglutaryl coenzyme A reductase) reduces the growth of intracellular S. enterica serovar Typhimurium and has no effect on extracellular bacterial growth. Selectively inhibiting synthesis of downstream sterol components has no effect on infection, suggesting that the effect of statins on host nonsterol intermediates is detrimental to bacterial growth. Furthermore, statins also reduce bacterial proliferation in the S. enterica serovar Typhimurium mouse model. This suggests that blocking the production of nonsterol precursors in the host cell can be used to reduce infection.
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Affiliation(s)
- Drew M Catron
- Departments of Pathology and Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA
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Berger A, Rein D, Kratky E, Monnard I, Hajjaj H, Meirim I, Piguet-Welsch C, Hauser J, Mace K, Niederberger P. Cholesterol-lowering properties of Ganoderma lucidum in vitro, ex vivo, and in hamsters and minipigs. Lipids Health Dis 2004; 3:2. [PMID: 14969592 PMCID: PMC385249 DOI: 10.1186/1476-511x-3-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2004] [Accepted: 02/18/2004] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION There has been renewed interest in mushroom medicinal properties. We studied cholesterol lowering properties of Ganoderma lucidum (Gl), a renowned medicinal species. RESULTS Organic fractions containing oxygenated lanosterol derivatives inhibited cholesterol synthesis in T9A4 hepatocytes. In hamsters, 5% Gl did not effect LDL; but decreased total cholesterol (TC) 9.8%, and HDL 11.2%. Gl (2.5 and 5%) had effects on several fecal neutral sterols and bile acids. Both Gl doses reduced hepatic microsomal ex-vivo HMG-CoA reductase activity. In minipigs, 2.5 Gl decreased TC, LDL- and HDL cholesterol 20, 27, and 18%, respectively (P < 0.05); increased fecal cholestanol and coprostanol; and decreased cholate. CONCLUSIONS Overall, Gl has potential to reduce LDL cholesterol in vivo through various mechanisms. Next steps are to: fully characterize bioactive components in lipid soluble/insoluble fractions; evaluate bioactivity of isolated fractions; and examine human cholesterol lowering properties. Innovative new cholesterol-lowering foods and medicines containing Gl are envisioned.
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Affiliation(s)
- A Berger
- Nestlé Research Center, Lausanne 26, 1000, Switzerland
- Paradigm Genetics, Research Triangle Park, NC 27709-4528, USA
| | - D Rein
- Nestlé Research Center, Lausanne 26, 1000, Switzerland
- BASF Plant Science Holding GmbH, Agricultural Center, BPH-Li 555, Limburgerhof, 67114, Germany
| | - E Kratky
- Nestlé Research Center, Lausanne 26, 1000, Switzerland
| | - I Monnard
- Nestlé Research Center, Lausanne 26, 1000, Switzerland
| | - H Hajjaj
- Nestlé Research Center, Lausanne 26, 1000, Switzerland
- Univerity des Sciences et de Technologie de Lille, B.P. 179, Villeneuve d'Ascq Cedex, 59653, France
| | - I Meirim
- Nestlé Research Center, Lausanne 26, 1000, Switzerland
| | | | - J Hauser
- Nestlé Research Center, Lausanne 26, 1000, Switzerland
- University of Lausanne, Institut de Biologie Cellulaire et de Morphologie, 1015, Lausanne, Switzerland
| | - K Mace
- Nestlé Research Center, Lausanne 26, 1000, Switzerland
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Vecka M, Tvrzická E, Stanková B, Novák F, Nováková O, Zák A. Hypolipidemic Drugs Can Change the Composition of Rat Brain Lipids. TOHOKU J EXP MED 2004; 204:299-308. [PMID: 15572855 DOI: 10.1620/tjem.204.299] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Hypolipidemic drugs are potent serum cholesterol lowering agents used for prevention of coronary heart disease. In addition to their cholesterol lowering effect, these drugs exhibit both pleiotropic beneficial and various neurological side effects. Therefore, we analysed effect of the hypolipidemic drugs, fenofibrate and statins, on membrane lipid composition in the rat brain tissue. Male Wistar rats were given 0.1 mg of fenofibrate, lovastatin, pravastatin, fluvastatin or placebo (control) once daily for six weeks. In rats treated with lovastatin or pravastatin, decreased cholesterol and increased ceramide monohexoside contents in the brain tissue were observed in comparison with control. Treatment with fluvastatin or lovastatin resulted in increased sphingomyelin and decreased diphosphatidylglycerol contents. The most important changes in the fatty acid profile were observed in ceramide monohexosides; treatment with fluvastatin decreased the content of saturated and increased the content of polyunsaturated fatty acids. Fenofibrate treatment led to decreased content of saturated fatty acids in phosphatidylethanolamines. In conclusion, statin treatment resulted in the decreased content of cholesterol and diphosphatidylglycerol associated with the increased content of sphingolipids in the rat brain tissue. As cholesterol and sphingolipids are important components of brain membranes, the observed alterations in the composition brain lipids might be involved in genesis of neurological and mental symptoms following statin therapy.
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Affiliation(s)
- Marek Vecka
- First Faculty of Medicine, Charles University, Prague, Czech Republic.
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Bełtowski J, Wójcicka G, Jamroz A. Effect of 3-hydroxy-3-methylglutarylcoenzyme A Reductase Inhibitors (Statins) on Tissue Paraoxonase 1 and Plasma Platelet Activating Factor Acetylhydrolase Activities. J Cardiovasc Pharmacol 2004; 43:121-7. [PMID: 14668577 DOI: 10.1097/00005344-200401000-00018] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The authors investigated the effect of pravastatin and fluvastatin on paraoxonase 1 (PON1) activity in plasma, liver, heart, and kidney, as well as on plasma platelet activating factor acetylhydrolase (PAF-AH) in the rat. The animals received pravastatin at doses of 4 and 40 mg/kg/d or fluvastatin at doses of 2 or 20 mg/kg/d for 3 weeks. Fluvastatin (20 mg/kg/d) reduced plasma PON1 activity toward paraoxon and phenyl acetate by 23.6% and 17.4%, respectively. The lower dose of this drug as well as both doses of pravastatin had no effect on plasma PON1. PON1 activity toward paraoxon in the liver of rats treated with 20 mg/kg/d fluvastatin was 27.5% lower than in the control group, and the activity toward phenyl acetate was reduced by 25.4% and 35.9% in rats receiving 2 and 20 mg/kg/d of this drug, respectively. Fluvastatin at 2 and 20 mg/kg/d also decreased cardiac PON1 by 31.3% and 27.3%, respectively. Both statins reduced PON1 activity in the renal cortex and medulla. Statins had no effect on plasma PAF-AH. It is concluded that fluvastatin reduces PON1 activity more efficiently than does pravastatin. Reducing effect on PON1 may negatively modulate atheroprotective potential of statins and may contribute to differences in antiatherosclerotic properties of different drugs in this group.
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Affiliation(s)
- Jerzy Bełtowski
- Department of Paraphysiology, Medical University, Lublin, Poland.
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Elokdah H, Sulkowski TS, Abou-Gharbia M, Butera JA, Chai SY, McFarlane GR, McKean ML, Babiak JL, Adelman SJ, Quinet EM. Design, Synthesis, and Biological Evaluation of Thio-Containing Compounds with Serum HDL-Cholesterol-Elevating Properties. J Med Chem 2003; 47:681-95. [PMID: 14736248 DOI: 10.1021/jm030219z] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel series of substituted sulfanyldihydroimidazolones (1) that modulates high-density lipoprotein cholesterol (HDL-C) has been reported to have HDL-elevating properties in several animal models. Concerns about the chemical and metabolic stability of 1 directed us to explore the structure-activity relationship (SAR) of a related series of substituted thiohydantoins (2). Expansion of the scope of the thiohydantoin series led to exploration of compounds in related thio-containing ring systems 3-7 and the N-cyanoguanidine derivative 8. Compounds were tested sequentially in three animal models to assess their HDL-C elevating efficacy and safety profiles. Further evaluation of selected compounds in a dose-response paradigm culminated in the identification of compound 2.39 as a candidate compound for advanced preclinical studies.
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Affiliation(s)
- Hassan Elokdah
- Medicinal Chemistry, Wyeth Research, CN 8000, Princeton, New Jersey 08543, USA.
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Gouédard C, Koum-Besson N, Barouki R, Morel Y. Opposite regulation of the human paraoxonase-1 gene PON-1 by fenofibrate and statins. Mol Pharmacol 2003; 63:945-56. [PMID: 12644596 DOI: 10.1124/mol.63.4.945] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The human paraoxonase-1 (PON-1) is a serum high-density lipoprotein-associated phosphotriesterase secreted mainly by the liver. This enzyme is able to hydrolyze toxic organophosphate xenobiotics, endogenous oxidized phospholipids, and homocysteine thiolactone. Physiologically, it is thought to protect against cardiovascular diseases. The level of PON-1 gene expression is a major determinant of paraoxonase-1 status but little is known regarding the regulation of this gene. We identified several transcription start sites and characterized the regulation of its promoter by fibrates and statins. In HuH7 human hepatoma cells, the PON-1 secreted enzymatic activity and mRNA levels were increased by fenofibric acid (approximately 70%) and decreased by several statins (approximately 50%). Transient and stable transfection assays in HuH7 cells indicated that the modulation of the mRNA and enzymatic activity levels could be accounted for by the regulation of the PON-1 gene promoter activity by these drugs. These effects are probably not mediated by the PPAR alpha because over-expression of this receptor decreased the fibrate effect and did not modify statins activity. The repressive effect of statins is reversed by mevalonate and 22(R)-hydroxycholesterol, suggesting the involvement of the liver X receptor in the mechanism. The opposite effects of fenofibrate and statins could be consistent with clinical data on homocysteine levels after hypolipidemic drug treatment. Regarding the toxicological aspects, the induction achieved with fenofibric acid, although limited, could increase organophosphate metabolism and may be relevant in certain conditions for protective treatments.
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Affiliation(s)
- Cédric Gouédard
- Institut National de la Santé et de la Recherche Médicale Unité-490, Centre Universitaire des Saints-Pères, Paris, France
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Kirsch C, Eckert GP, Mueller WE. Statin effects on cholesterol micro-domains in brain plasma membranes. Biochem Pharmacol 2003; 65:843-56. [PMID: 12628479 DOI: 10.1016/s0006-2952(02)01654-4] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recent epidemiological studies revealed inhibitors of the hydroxymethylglutaryl-coenzyme A reductase, so-called statins, to be effective in lowering the prevalence of Alzheimer's disease (AD). In vitro, statins strongly reduced the cellular amyloid beta-protein load by modulating the processing of the amyloid beta precursor protein. Both observations are probably linked to cellular cholesterol homeostasis in brain. So far, little is known about brain effects of statins. Recently, we could demonstrate that treatment of mice with the lipophilic compound lovastatin resulted in a discrete reduction of brain membrane cholesterol levels. To follow up these findings, we subsequently carried out a further in vivo study including lovastatin and simvastatin as lipophilic agents, as well as pravastatin as a hydrophilic compound, focussing on their efficiency to affect subcellular membrane cholesterol pools in synaptosomal plasma membranes of mice. In contrast to the hydrophilic pravastatin, the lipophilic lovastatin and simvastatin strongly reduced the levels of free cholesterol in SPM. Interestingly, lovastatin and pravastatin but not simvastatin significantly reduced cholesterol levels in the exofacial membrane leaflet. These changes were accompanied by modified membrane bulk fluidity. All three statins reduced the expression of the raft marker protein flotillin. Alterations in transbilayer cholesterol distribution have been suggested as the underlying mechanism that forces amyloidogenic processing of APP in AD. Thus, our data give some first insight in the mode of action of statins to reduce the prevalence of AD in clinical trials.
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Affiliation(s)
- Christopher Kirsch
- Department of Pharmacology, Biocenter Niederursel, University of Frankfurt, Marie-Curie-Str. 9, Germany
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Baptista T, Araujo de Baptista E, Ying Kin NMKN, Beaulieu S, Walker D, Joober R, Lalonde J, Richard D. Comparative effects of the antipsychotics sulpiride or risperidone in rats. I: bodyweight, food intake, body composition, hormones and glucose tolerance. Brain Res 2002; 957:144-51. [PMID: 12443990 DOI: 10.1016/s0006-8993(02)03616-8] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Obesity and related metabolic disorders are important side effects of some antipsychotic drugs (APs). The currently available animal model of AP-induced bodyweight gain (BWG) in rats is based on administration of sulpiride (SUL). However, this model has important limitations. For example, SUL is a pure dopamine antagonist, whereas most APs in current clinical use interact with multiple neurotransmitter receptors involved in food intake (FI) and metabolism regulation. Therefore, we evaluated the effects of risperidone (RIS, 0.125, 0.25 or 0.5 mg/kg during 16 days) on BWG and FI in male and female rats. Comparison between RIS (0.5 mg/kg), SUL (20 mg/kg) and vehicle (VEH) during 12 days was also conducted in females. In male rats, RIS did not significantly affect BWG, FI, glucose tolerance or leptin levels, even though prolactin and corticosterone were significantly elevated. In females, both APs significantly increased BWG and FI, but the effect was stronger with SUL. The BWG was significantly associated with an increase in body fat. Serum leptin levels were increased only in SUL-treated rats. The area under the curve for glucose (AUGC) was significantly lower in the SUL group, but it was similar for insulin in all treatment groups. The area under the curve for insulin (AUIC) and BWG positively correlated only in the RIS group. Prolactin and corticosterone were significantly increased by both APs. Serum estradiol levels were significantly increased by RIS but not by SUL, but progesterone levels were similar in both groups. The observed positive correlation between BWG and the AUIC during RIS administration suggests that this agent may represent a better model of AP administration in humans. The animal model of RIS-induced obesity in rats might be improved by testing other doses, route of administration and type of diet.
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Affiliation(s)
- Trino Baptista
- Department of Physiology, Los Andes University Medical School, 5101-A, Mèrida, Venezuela.
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Sauerberg P, Pettersson I, Jeppesen L, Bury PS, Mogensen JP, Wassermann K, Brand CL, Sturis J, Wöldike HF, Fleckner J, Andersen AST, Mortensen SB, Svensson LA, Rasmussen HB, Lehmann SV, Polivka Z, Sindelar K, Panajotova V, Ynddal L, Wulff EM. Novel tricyclic-alpha-alkyloxyphenylpropionic acids: dual PPARalpha/gamma agonists with hypolipidemic and antidiabetic activity. J Med Chem 2002; 45:789-804. [PMID: 11831892 DOI: 10.1021/jm010964g] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Synthesis and structure-activity relationships of tricyclic alpha-ethoxy-phenylpropionic acid derivatives guided by in vitro PPARalpha and PPARgamma transactivation data and computer modeling led to the identification of the novel carbazole analogue, 3q, with dual PPARalpha (EC(50) = 0.36 microM) and PPARgamma (EC(50) = 0.17 microM) activity in vitro. Ten days treatment of db/db mice with 3q improved the insulin sensitivity, as measured by OGTT, better than that seen with both pioglitazone and rosiglitazone treatment, suggesting in vivo PPARgamma activity. Likewise, 3q lowered plasma triglycerides and cholesterol in high cholesterol fed rats after 4 days treatment, indicating in vivo PPARalpha activity. Investigations of the pharmacokinetics of selected compounds suggested that extended drug exposure improved the in vivo activity of in vitro active compounds.
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Affiliation(s)
- Per Sauerberg
- Novo Nordisk A/S, Novo Nordisk Park E9 2.02, 2760 Måløv, Denmark.
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