1
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Hypocholesterolemic effects of soy protein isolates from soybeans differing in 7S and 11S globulin subunits vary in rats fed a high cholesterol diet. J Funct Foods 2022. [DOI: 10.1016/j.jff.2022.105347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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2
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Beneficial Effects of Three Dietary Cyclodextrins on Preventing Fat Accumulation and Remodeling Gut Microbiota in Mice Fed a High-Fat Diet. Foods 2022; 11:foods11081118. [PMID: 35454706 PMCID: PMC9031782 DOI: 10.3390/foods11081118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/02/2022] [Accepted: 04/08/2022] [Indexed: 11/23/2022] Open
Abstract
Globally, obesity and its metabolic complications, which are intimately linked to diet, are major public health problems. Cyclodextrins (CDs) are cyclic oligosaccharides consisting of (α-1,4)-linked D-glucopyranose units that can reduce fat bioavailability and affect metabolism by improving intestinal flora as prebiotics. We compared the effects of three CDs on preventing fat accumulation and remodeling gut microbiota in a high-fat diet-fed C57BL/6J mouse model. α-CD maximized energy expenditure by 12.53%, caused the RER value to drop from 0.814 to 0.788, and increased the proportion of fatty acid oxidation for energy supply. β-CD supplementation resulted in a marked 24.53% reduction in weight gain and a decrease in epididymal-fat-relative weight from 3.76% to 2.09%. It also minimized ectopic fat deposition and improved blood lipid parameters. γ-CD maximized the concentration of SCFAs in the cecum from 6.29 to 15.31 μmol/g. All three CDs reduced the abundance ratio of Firmicutes and Bacteroidetes to a low-fat diet level, increased the abundance of Lactobacillus and Akkermansia, and reduced the abundance of Allobaculum and Ruminococcus. These findings imply that a combination of multiple CDs may exert superior effects as a potential strategy for obesity prevention.
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Juste C, Gérard P. Cholesterol-to-Coprostanol Conversion by the Gut Microbiota: What We Know, Suspect, and Ignore. Microorganisms 2021; 9:1881. [PMID: 34576776 PMCID: PMC8468837 DOI: 10.3390/microorganisms9091881] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/24/2021] [Accepted: 09/01/2021] [Indexed: 12/12/2022] Open
Abstract
Every day, up to 1 g of cholesterol, composed of the unabsorbed dietary cholesterol, the biliary cholesterol secretion, and cholesterol of cells sloughed from the intestinal epithelium, enters the colon. All cholesterol arriving in the large intestine can be metabolized by the colonic bacteria. Cholesterol is mainly converted into coprostanol, a non-absorbable sterol that is excreted in the feces. Interestingly, cholesterol-to-coprostanol conversion in human populations is variable, with a majority of high converters and a minority of low or inefficient converters. Two major pathways have been proposed, one involving the direct stereospecific reduction of the Δ5 double bond direct while the indirect pathway involves the intermediate formation of 4-cholelesten-3-one and coprostanone. Despite the fact that intestinal cholesterol conversion was discovered more than a century ago, only a few cholesterol-to-coprostanol-converting bacterial strains have been isolated and characterized. Moreover, the responsible genes were mainly unknown until recently. Interestingly, cholesterol-to-coprostanol conversion is highly regulated by the diet. Finally, this gut bacterial metabolism has been linked to health and disease, and recent evidence suggests it could contribute to lower blood cholesterol and cardiovascular risks.
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Affiliation(s)
| | - Philippe Gérard
- AgroParisTech, Micalis Institute, Université Paris-Saclay, INRAE, 78350 Jouy-en-Josas, France;
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4
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Cyclodextrin Monomers and Polymers for Drug Activity Enhancement. Polymers (Basel) 2021; 13:polym13111684. [PMID: 34064190 PMCID: PMC8196804 DOI: 10.3390/polym13111684] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/18/2021] [Accepted: 05/19/2021] [Indexed: 12/13/2022] Open
Abstract
Cyclodextrins (CDs) and cyclodextrin (CD)-based polymers are well-known complexing agents. One of their distinctive features is to increase the quantity of a drug in a solution or improve its delivery. However, in certain instances, the activity of the solutions is increased not only due to the increase of the drug dose but also due to the drug complexation. Based on numerous studies reviewed, the drug appeared more active in a complex form. This review aims to summarize the performance of CDs and CD-based polymers as activity enhancers. Accordingly, the review is divided into two parts, i.e., the effect of CDs as active drugs and as enhancers in antimicrobials, antivirals, cardiovascular diseases, cancer, neuroprotective agents, and antioxidants.
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Matencio A, Caldera F, Cecone C, López-Nicolás JM, Trotta F. Cyclic Oligosaccharides as Active Drugs, an Updated Review. Pharmaceuticals (Basel) 2020; 13:E281. [PMID: 33003610 PMCID: PMC7601923 DOI: 10.3390/ph13100281] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 09/26/2020] [Accepted: 09/27/2020] [Indexed: 12/13/2022] Open
Abstract
There have been many reviews of the cyclic oligosaccharide cyclodextrin (CD) and CD-based materials used for drug delivery, but the capacity of CDs to complex different agents and their own intrinsic properties suggest they might also be considered for use as active drugs, not only as carriers. The aim of this review is to summarize the direct use of CDs as drugs, without using its complexing potential with other substances. The direct application of another oligosaccharide called cyclic nigerosyl-1,6-nigerose (CNN) is also described. The review is divided into lipid-related diseases, aggregation diseases, antiviral and antiparasitic activities, anti-anesthetic agent, function in diet, removal of organic toxins, CDs and collagen, cell differentiation, and finally, their use in contact lenses in which no drug other than CDs are involved. In the case of CNN, its application as a dietary supplement and immunological modulator is explained. Finally, a critical structure-activity explanation is provided.
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Affiliation(s)
- Adrián Matencio
- Dipartimento di Chimica, Università di Torino, via P. Giuria 7, 10125 Torino, Italy; (F.C.); (C.C.); (F.T.)
| | - Fabrizio Caldera
- Dipartimento di Chimica, Università di Torino, via P. Giuria 7, 10125 Torino, Italy; (F.C.); (C.C.); (F.T.)
| | - Claudio Cecone
- Dipartimento di Chimica, Università di Torino, via P. Giuria 7, 10125 Torino, Italy; (F.C.); (C.C.); (F.T.)
| | - José Manuel López-Nicolás
- Departamento de Bioquímica y Biología Molecular A, Unidad Docente de Biología, Facultad de Veterinaria, Regional Campus of International Excellence “Campus Mare Nostrum”, Universidad de Murcia, 30100 Espinardo, Murcia, Spain;
| | - Francesco Trotta
- Dipartimento di Chimica, Università di Torino, via P. Giuria 7, 10125 Torino, Italy; (F.C.); (C.C.); (F.T.)
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6
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Eggink HM, van Nierop FS, Schooneman MG, Boelen A, Kalsbeek A, Koehorst M, ten Have GA, de Brauw LM, Groen AK, Romijn JA, Deutz NE, Soeters MR. Transhepatic bile acid kinetics in pigs and humans. Clin Nutr 2018; 37:1406-1414. [DOI: 10.1016/j.clnu.2017.06.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/13/2017] [Accepted: 06/13/2017] [Indexed: 01/06/2023]
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7
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Cheong AM, Jessica Koh JX, Patrick NO, Tan CP, Nyam KL. Hypocholesterolemic Effects of Kenaf Seed Oil, Macroemulsion, and Nanoemulsion in High-Cholesterol Diet Induced Rats. J Food Sci 2018; 83:854-863. [PMID: 29412455 DOI: 10.1111/1750-3841.14038] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/23/2017] [Accepted: 12/11/2017] [Indexed: 12/17/2022]
Abstract
This study aimed to evaluate the effect of kenaf seed oil (KSO), kenaf seed oil-in-water macroemulsion (KSOM), kenaf seed oil-in-water nanoemulsions (KSON), and emulsifier mixtures (EM) on serum lipid profile, liver oxidative status, and histopathological changes in high-cholesterol fed rats. Stability and characteristic of KSOM and KSON were carried out prior to in vivo study. Forty-two Sprague-Dawley rats were divided into 7 groups (6 rats each) and induced hypercholesterolemia by feeding high cholesterol diet (HCD) for 14 days prior to treatments. Different treatments were introduced on day 15 to 29 while supplemented with HCD and removal of HCD during treatment on day 30 to 43, except for HCD group. Body weight and serum lipid profiles were measured at 3 different points: after hypercholesterolemia was induced, on day 29, and at the end of the experiment. Relative liver weight, atherogenic index, coronary risk index, and fecal total bile acids were also determined at the end of experiment. KSON showed significantly higher stability than KSOM and FTIR exhibited good encapsulation of KSO after 1.5 years of storage. Serum total cholesterol, low density lipoprotein cholesterol, lipid peroxidation levels in HCD group without treatment were significantly higher compared to normal control group and all treatment groups. All samples demonstrated hypocholesterolemic effect, but KSON exhibited higher efficiency in cholesterol-lowering properties, weight control and decreased liver fat as confirmed by histopathological evaluation. The overall results revealed that the efficacy of different treatments was in descending order of KSON, KSO, KSOM, and EM. PRACTICAL APPLICATION Kenaf seed oil-in-water nanoemulsion (KSON) has the potential to be used as a natural alternative to the synthetic hypocholesterolemic drug in the future. However, larger sample size and clinical trial are needed to confirm on this potential application. In addition, treatment with KSON was suggested to prevent cardiovascular disease and fatty liver.
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Affiliation(s)
- Ai Mun Cheong
- Dept. of Food Science with Nutrition, Faculty of Applied Sciences, UCSI Univ., 5600, Kuala Lumpur, Malaysia
| | - Jue Xi Jessica Koh
- Dept. of Food Science with Nutrition, Faculty of Applied Sciences, UCSI Univ., 5600, Kuala Lumpur, Malaysia
| | | | - Chin Ping Tan
- Dept. of Food Technology, Faculty of Food Science and Technology, Univ. Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - Kar Lin Nyam
- Dept. of Food Science with Nutrition, Faculty of Applied Sciences, UCSI Univ., 5600, Kuala Lumpur, Malaysia
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8
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Mistry RH, Verkade HJ, Tietge UJF. Absence of intestinal microbiota increases ß-cyclodextrin stimulated reverse cholesterol transport. Mol Nutr Food Res 2017; 61. [PMID: 28087885 DOI: 10.1002/mnfr.201600674] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 12/14/2016] [Accepted: 12/16/2016] [Indexed: 11/07/2022]
Abstract
SCOPE Non-digestible oligosaccharides are used as prebiotics for perceived health benefits, among these modulating lipid metabolism. However, the mechanisms of action are incompletely understood. The present study characterized the impact of dietary ß-cyclodextrin (ßCD, 10%, w/w), a cyclic oligosaccharide, on sterol metabolism and reverse cholesterol transport (RCT) in conventional and also germ-free mice to establish dependency on metabolism by intestinal bacteria. METHODS AND RESULTS In conventional ßCD-fed C57BL/6J wild-type mice plasma cholesterol decreased significantly (-40%, p < 0.05), largely within HDL, while fecal neutral sterol excretion increased (3-fold, p < 0.01) and fecal bile acid excretion was unchanged. Hepatic cholesterol levels and biliary cholesterol secretion were unaltered. Changes in cholesterol metabolism translated into increased macrophage-to-feces RCT in ßCD-administered mice (1.5-fold, p < 0.05). In germ-free C57BL/6J mice ßCD similarly lowered plasma cholesterol (-40%, p < 0.05). However, ßCD increased fecal neutral sterol excretion (7.5-fold, p < 0.01), bile acid excretion (2-fold, p < 0.05) and RCT (2.5-fold, p < 0.01) even more substantially in germ-free mice compared with the effect in conventional mice. CONCLUSION In summary, this study demonstrates that ßCD lowers plasma cholesterol levels and increases fecal cholesterol excretion from a RCT-relevant pool. Intestinal bacteria decrease the impact of ßCD on RCT. These data suggest that dietary ßCD might have cardiovascular health benefits.
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Affiliation(s)
- Rima H Mistry
- Department of Pediatrics, Center for Liver, Digestive, and Metabolic Diseases, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Henkjan J Verkade
- Department of Pediatrics, Center for Liver, Digestive, and Metabolic Diseases, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Uwe J F Tietge
- Department of Pediatrics, Center for Liver, Digestive, and Metabolic Diseases, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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Fenyvesi É, Vikmon M, Szente L. Cyclodextrins in Food Technology and Human Nutrition: Benefits and Limitations. Crit Rev Food Sci Nutr 2017; 56:1981-2004. [PMID: 25764389 DOI: 10.1080/10408398.2013.809513] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Cyclodextrins are tasteless, odorless, nondigestible, noncaloric, noncariogenic saccharides, which reduce the digestion of carbohydrates and lipids. They have low glycemic index and decrease the glycemic index of the food. They are either non- or only partly digestible by the enzymes of the human gastrointestinal (GI) tract and fermented by the gut microflora. Based on these properties, cyclodextrins are dietary fibers useful for controlling the body weight and blood lipid profile. They are prebiotics, improve the intestinal microflora by selective proliferation of bifidobacteria. These antiobesity and anti-diabetic effects make them bioactive food supplements and nutraceuticals. In this review, these features are evaluated for α-, β- and γ-cyclodextrins, which are the cyclodextrin variants approved by authorities for food applications. The mechanisms behind these effects are reviewed together with the applications as solubilizers, stabilizers of dietary lipids, such as unsaturated fatty acids, phytosterols, vitamins, flavonoids, carotenoids and other nutraceuticals. The recent applications of cyclodextrins for reducing unwanted components, such as trans-fats, allergens, mycotoxins, acrylamides, bitter compounds, as well as in smart active packaging of foods are also overviewed.
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Affiliation(s)
- É Fenyvesi
- a CycloLab Cyclodextrin Research & Development Laboratory, Ltd. , Budapest , Hungary
| | - M Vikmon
- a CycloLab Cyclodextrin Research & Development Laboratory, Ltd. , Budapest , Hungary
| | - L Szente
- a CycloLab Cyclodextrin Research & Development Laboratory, Ltd. , Budapest , Hungary
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Mendonça PV, Serra AC, Silva CL, Simões S, Coelho JF. Polymeric bile acid sequestrants—Synthesis using conventional methods and new approaches based on “controlled”/living radical polymerization. Prog Polym Sci 2013. [DOI: 10.1016/j.progpolymsci.2012.09.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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11
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Erickson RP. Current controversies in Niemann-Pick C1 disease: steroids or gangliosides; neurons or neurons and glia. J Appl Genet 2013; 54:215-24. [PMID: 23292954 DOI: 10.1007/s13353-012-0130-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 12/10/2012] [Accepted: 12/11/2012] [Indexed: 11/28/2022]
Abstract
There has been a recent explosion in research on Niemann-Pick type C disease. Much of the work has used mouse models or cells in culture to elucidate the pathophysiological mechanisms resulting in the phenotype of the disease. This work has generated several contrasting views on the mechanism, which are labeled 'controversies' here. In this review, two of these controversies are explored. The first concerns which stored materials are causative in the disease: cholesterol, gangliosides and sphingolipids, or something else? The second concerns which cells in the body require Npc1 in order to function properly: somatic cells, neurons only, or neurons and glia? For the first controversy, a clear answer has emerged. More research will be needed in order to definitively solve the second controversy.
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Affiliation(s)
- Robert P Erickson
- Department of Pediatrics, University of Arizona, Tucson, AZ 85724-5073, USA.
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12
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Muralidhar A, Borbon IA, Esharif DM, Ke W, Manacheril R, Daines M, Erickson RP. Pulmonary function and pathology in hydroxypropyl-beta-cyclodextin-treated and untreated Npc1⁻/⁻ mice. Mol Genet Metab 2011; 103:142-7. [PMID: 21459030 PMCID: PMC3107736 DOI: 10.1016/j.ymgme.2011.03.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 02/28/2011] [Accepted: 03/01/2011] [Indexed: 11/19/2022]
Abstract
Lung dysfunction is an important part of the pathology of the neurodegenerative disorder, Niemann-Pick C1 (NPC1). We have studied the pulmonary disease in the Npc1(NIH/NIH) mouse model. On histology, we find large numbers of alveolar foamy macrophages but no alveolar proteinosis. Lung weight as percent of body weight was markedly increased; using the flexiVent small animal ventilator (SCIREQ, Inc.), we find inspiratory capacity, elastance and hysterisivity to be increased while resistance was not changed. Cholesterol measurements show a doubling of lung cholesterol levels. Collagen is also increased. Treatment of Npc1(-/-) mice with hydroxypropyl-β-cyclodextrin (HPBCD), despite efficacious effects in brain and liver, results in little difference from age-matched controls (using a CNS-expressed transgene to extend the life expectancy of the Npc1(-/-) mice) for these variables.
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Affiliation(s)
| | - Ivan A Borbon
- Dept of Pediatrics, University of Arizona, Tucson, AZ, 85724
| | | | - Wangjing Ke
- Dept of Pediatrics, University of Arizona, Tucson, AZ, 85724
| | - Rinu Manacheril
- Dept of Pediatrics, University of Arizona, Tucson, AZ, 85724
| | - Michael Daines
- Dept of Pediatrics, University of Arizona, Tucson, AZ, 85724
- Arizona Respiratory Center, University of Arizona, Tucson, AZ, 85724
| | - Robert P Erickson
- Dept of Pediatrics, University of Arizona, Tucson, AZ, 85724
- Dept of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, 85724
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Ward S, O'Donnell P, Fernandez S, Vite CH. 2-hydroxypropyl-beta-cyclodextrin raises hearing threshold in normal cats and in cats with Niemann-Pick type C disease. Pediatr Res 2010; 68:52-6. [PMID: 20357695 PMCID: PMC2913583 DOI: 10.1203/pdr.0b013e3181df4623] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
2-hydroxypropyl-beta-cyclodextrin (HPbetaCD) is a promising experimental therapy for Niemann-Pick type C disease that improved intracellular cholesterol transport, substantially reduced neurodegeneration and hepatic disease, and increased lifespan in npc1 mice. On the basis of favorable treatment outcome in mice, HPbetaCD is being evaluated as a therapy in children with Niemann-Pick type C (NPC) disease. We evaluated the efficacy of HPbetaCD in the feline model of NPC disease and recognized a dose-dependent increase in hearing threshold associated with therapy as determined by brain stem auditory evoked response (BAER) testing. To further assess the effect of HPbetaCD on hearing threshold, normal cats were administered the drug s.c. at either 4000 mg/kg or 8000 mg/kg body weight, or intrathecally at a dose of 4000 mg/kg brain weight. HPbetaCD caused a significant increase in hearing threshold following one dose of 8000 mg/kg s.c. or 120 mg intrathecally, and the effect was maintained for at least 12 weeks. Repeated weekly s.c. administration of 4000 mg/kg HPbetaCD resulted in a similar increase in hearing threshold. These studies are the first to describe a specific negative effect of HPbetaCD on the auditory system and suggest the need for auditory testing in patients receiving similar doses of HPbetaCD.
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Affiliation(s)
- Sarah Ward
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Martins JM, Neves JA, Freitas A, Tirapicos JL. Betaine supplementation affects the cholesterol but not the lipid profile of pigs. EUR J LIPID SCI TECH 2010. [DOI: 10.1002/ejlt.200900066] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- José M. Martins
- Laboratório de Metabolismo Animal, ICAM/Universidade de Évora, 7002‐554 Évora, Portugal
| | - José A. Neves
- Departamento de Zootecnia, Universidade de Évora, 7002‐554 Évora, Portugal
| | - Amadeu Freitas
- Departamento de Zootecnia, Universidade de Évora, 7002‐554 Évora, Portugal
| | - José L. Tirapicos
- Departamento de Medicina Veterinária, Universidade de Évora, 7002‐554 Évora, Portugal
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Huang X, Tang J, Zhou Q, Lu H, Wu Y, Wu W. Polysaccharide from fuzi (FPS) prevents hypercholesterolemia in rats. Lipids Health Dis 2010; 9:9. [PMID: 20109183 PMCID: PMC2835708 DOI: 10.1186/1476-511x-9-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Accepted: 01/28/2010] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND AIM Polysaccharide from fuzi (FPS), a Chinese herbal medicine extract, has been demonstrated to exert lipid lowering affects. In this study we examined potential mechanisms underlying this affect, specifically alterations in expression of the LDL-receptor (LDL-R), 3-hydroxy-3-methyl glutaryl (HMG)-CoA reductase and cytochrome P450 7alpha-1 (CYP7alpha-1), using a rat model of hypercholesterolemia. METHODS AND RESULTS Male rats were fed either a normal or high cholesterol (HC) diet for two-weeks. Half of the rats on the HC diet were orally gavaged with FPS (224 mg/kg, 448 mg/kg or 896 mg/kg diet) daily. Serum lipid levels were quantified at end of the study period as were liver levels of LDL-R protein and mRNA expression of CYP7alpha-1 and HMG-CoA. Serum cholesterol and LDL-C concentrations were significantly elevated from control in HC rats, but not in those treated with FPS (P < 0.05). LDL-R expression was significantly decreased in the HC group compared to control (P < 0.05), but significantly increased in the FPS group (P < 0.05). HMG-CoA mRNA levels were significantly increased in the HC group compared both other groups (P < 0.05), while CYP7alpha-1 expression was significantly higher in the FPS group compared to both other groups (P < 0.05). CONCLUSION These findings suggest that the cholesterol lowering effect of FPS in hypercholesteremic rats is caused at least in part by increased hepatic LDL-R and CYP7alpha-1 expression and decreased HMG-CoA expression. Further study is needed to determine precisely where and how FPS exerts these effects. FPS offers potential as a therapeutic agent for the treatment of hypercholesterolemia.
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Affiliation(s)
- Xiongqing Huang
- Department of Anesthesiology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, PR China
| | - Juan Tang
- Guangzhou Critical Care Medicine Department, Guangzhou Women and Children's Medical Center, Guangzhou 510120, PR China
| | - Qin Zhou
- Department of Anesthesiology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, PR China
| | - Hanping Lu
- Department of Nuclear Medicine, Zhongshan Medical College, Sun Yat-sen University, Guangzhou 510089, PR China
| | - Yiling Wu
- Hebei Yiling Pharmaceutical Research Institute, Shijiazhuang 050035, PR China
| | - Weikang Wu
- Institute of Integrated Traditional Chinese and Western Medicine, Zhongshan Medical College, Sun Yat-sen University, Guangzhou 510089, PR China
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Lepercq P, Hermier D, David O, Michelin R, Gibard C, Beguet F, Relano P, Cayuela C, Juste C. Increasing ursodeoxycholic acid in the enterohepatic circulation of pigs through the administration of living bacteria. Br J Nutr 2007; 93:457-69. [PMID: 15946407 DOI: 10.1079/bjn20041386] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We investigated the feasibility of increasing ursodeoxycholic acid (UDCA) in the enterohepatic circulation of pigs by administering living bacteria capable of epimerising endogenous amidated chenodeoxycholic acid (CDCA) to UDCA. We first demonstrated that combining Bifidobacterium animalis DN-173 010, as a bile salt-hydrolysing bacterium, and Clostridium absonum ATCC 27555, as a CDCA to UDCA epimerising bacterium, led to the efficient epimerisation of glyco- and tauro-CDCA in vitro, with respective UDCA yields of 55·8 (se 2·8) and 36·6 (se 1·5)%. This strain combination was then administered to hypercholesterolaemic pigs over a 3-week period, as two daily preprandial doses of either viable (six experimental pigs) or heat-inactivated bacteria (six controls). The main effects of treatment were on unconjugated bile acids (P=0·035) and UDCA (P<0·0001) absorbed into the portal vein, which increased 1·6–1·7- and 3·5–7·5-fold, respectively, under administration of living compared with inactivated bacteria. In bile, UDCA did not increase significantly, but the increase in biliary lithocholic acid with time in the controls was not observed in the experimental pigs (P=0·007), and the same trend was observed in faeces. All other variables (biliary lipid equilibrium, plasma lipid levels and partition of cholesterol between the different lipoprotein classes) remained unaffected by treatment throughout the duration of the experiment. In conclusion, it is feasible to increase the bioavailability of UDCA to the intestine and the liver by administering active bacteria. This may represent an interesting new probiotic activity, provided that in future it could be expressed by a safe food micro-organism.
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Affiliation(s)
- Pascale Lepercq
- Unité d'Ecologie et de Physiologie du Système Digestif, Institut National de la Recherche Agronomique, 78352 Jouy-en-Josas Cedex, France
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17
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Morise A, Mourot J, Boué C, Combe N, Amsler G, Gripois D, Quignard-Boulangé A, Yvan-Charvet L, Fénart E, Weill P, Hermier D. Gender-related response of lipid metabolism to dietary fatty acids in the hamster. Br J Nutr 2007; 95:709-20. [PMID: 16571150 DOI: 10.1079/bjn20051721] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Gender and dietary fatty acids are involved in the regulation of lipid metabolism, disturbances of which can lead to pathologies such as metabolic syndrome or CVD. Possible interactions between these factors were investigated in male and female hamsters fed diets rich in either saturated fatty acids (‘butter’ diet) or in α-linolenic acid (‘linseed oil’ diet). Gender effect predominated over the diet effect on cholesterol (CH) metabolism; compared to males, females exhibited lower concentrations of plasma total CH (−20%,P<0·001), LDL-CH (−40%,P<0·001) and HDL-CH (−16%,P<0·001), together with higher LDL receptor (+40%) and lower HDL receptor (−60%) hepatic content. Triacylglycerol (TG) metabolism was affected by diet above all: compared to animals fed the ‘butter’ diet, those fed the ‘linseed oil’ diet exhibited lower plasma (−23%,P=0·046) and liver TG (−20%,P=0·026) concentration which may result from both an increased β-oxidation (P<0·001), without any change in PPARα mRNA, and a decreased hepatic lipogenesis (P=0·023), without increased sterol response element binding protein 1c (SREBP1c) mRNA. The response to diet was much more pronounced in males than in females, without gender effect on the transcription level of PPARα and SREBP1c. Finally, the ‘linseed oil’ diet decreased the insulin resistance index (−80%,P<0·001) with a more marked effect in males, in relation to their higher hepatic PPARγ expression (+90%,P=0·012). In conclusion, in our model, the response of either TG or CH to dietary fatty acids is modulated differently by gender. The possible relevance of these interactions to dietary practice should be taken into account in man.
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Affiliation(s)
- Anne Morise
- Laboratoire d'Endocrinologie de la Nutrition, Université Paris Sud, 91405 Orsay Cedex, France
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Martins JM, Riottot M, de Abreu MC, Viegas-Crespo AM, Lança MJ, Almeida JA, Freire JB, Bento OP. Cholesterol-lowering effects of dietary blue lupin (Lupinus angustifolius L.) in intact and ileorectal anastomosed pigs. J Lipid Res 2005; 46:1539-47. [PMID: 15834122 DOI: 10.1194/jlr.m500129-jlr200] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The present study was undertaken to investigate the effect of cholesterol-enriched casein (CAS) and blue lupin seed (BL) diets on the cholesterol metabolism of intact (INT) and ileorectal anastomosed (IRA) pigs. For 3 weeks, four groups of six pigs were allocated to the treatments (CAS-INT, CAS-IRA, BL-INT, and BL-IRA). Diet-induced hypercholesterolemia was inhibited by the BL through a substantial decrease in plasma LDL-cholesterol. The BL also reduced liver esterified and total cholesterol, increased hepatic LDL receptor synthesis and HMG-CoA reductase activity, and stimulated intestinal bile acid reabsorption. The neutral sterol output was higher in BL- than in CAS-fed pigs. The bile acid output was lower in IRA than in INT pigs. Surgery also prevented steroid microbial transformation, but it did not influence plasma cholesterol levels. These results suggest that the hypocholesterolemic effect of the BL, compared with the CAS, is attributable to impaired intestinal cholesterol absorption, probably involving increased bile acid reabsorption and higher contents of dietary phytosterols, both factors that reduce the micellar solubilization of cholesterol. Furthermore, according to our data, the contribution of the large intestine to cholesterol metabolism is very weak.
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Affiliation(s)
- José M Martins
- Laboratório de Metabolismo Animal, Instituto de Ciências Agrárias Mediterrânicas /Universidade de Evora, 7002-554 Evora, Portugal.
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19
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Martins JM, Riottot M, de Abreu MC, Lança MJ, Viegas-Crespo AM, Almeida JA, Freire JB, Bento OP. Dietary raw peas (Pisum sativum L.) reduce plasma total and LDL cholesterol and hepatic esterified cholesterol in intact and ileorectal anastomosed pigs fed cholesterol-rich diets. J Nutr 2004; 134:3305-12. [PMID: 15570030 DOI: 10.1093/jn/134.12.3305] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Previous studies demonstrated the cholesterol-lowering effect of dietary legumes (mainly soybeans) in animals and humans, but the mechanisms by which they exert this effect are not completely understood. The contribution of the hindgut to this hypocholesterolemic effect is also not well documented. The present work was undertaken to investigate the effect of cholesterol-enriched (2.8 g/kg) casein (C) and raw pea seed (RP) diets on the cholesterol metabolism of intact (I) and ileorectal anastomosed (IRA) growing pigs. Four groups of 6 pigs were allocated to the treatments (C-I, C-IRA, RP-I, and RP-IRA pigs) for 3 wk. Plasma total cholesterol was lowered by the RP diet through a significant decrease in LDL cholesterol. The RP diet also decreased the hepatic concentration of esterified cholesterol and increased 3-hydroxy-3-methylglutaryl CoA reductase activity and LDL receptor synthesis. The biliary total cholesterol and bile acid concentrations were greater in RP- than in C-fed pigs. In addition, fecal bile acid output was higher in RP-fed pigs. The cecum-colon by-pass inhibited cholesterol and beta-sitosterol microbial transformation, lowered the bile acid output, and increased the primary to secondary bile acid output ratio, but its influence on cholesterolemia was negligible. These results suggest a hypocholesterolemic effect of the raw pea diet probably due to increased fecal bile acid output and an increased biliary bile acid concentration.
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Affiliation(s)
- José M Martins
- Laboratório de Metabolismo Animal, ICAM/Universidade de Evora, 7002-554 Evora, Portugal.
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Abstract
Cyclodextrins (CyDs) have traditionally been used for dissolving hydrophobic chemicals into aqueous media, and more recently, for inducing cholesterol efflux from lipid-laden cells as a proposed mechanism for reversal of cardiovascular disease. This review discusses the potential of delivering therapeutic oligonucleotides to solid tumours using CyD molecules. The physicochemical properties of these oligosaccharide molecules, and the barriers posed by the solid tumour itself, factors that affect may affect the uptake of oligonucleotides by CyDs, are the major foci of this review.
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Affiliation(s)
- Crispin R Dass
- Genetic Technologies Pty. Ltd., Hanover St 3065 Fitzroy Australia.
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Morise A, Sérougne C, Gripois D, Blouquit MF, Lutton C, Hermier D. Effects of dietary alpha linolenic acid on cholesterol metabolism in male and female hamsters of the LPN strain. J Nutr Biochem 2004; 15:51-61. [PMID: 14711461 DOI: 10.1016/j.jnutbio.2003.10.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
N-3 polyunsaturated fatty acids and estrogens are recognized as protective factors of atherosclerosis, however their interactions on cholesterol metabolism remain unclear. Male and female hamsters were fed for 9 weeks diets containing 12.5% lipids and rich in either alpha-linolenic acid ("linseed" diet) or saturated fatty acids ("butter" diet). Hamsters fed the "linseed" diet exhibited lower plasma concentrations of cholesterol (-29%), total LDL (-35%) and HDL (-17%), glucose (-20%), insulin (-40%) and of the LDL-cholesterol/HDL-cholesterol ratio (-27%) than those fed the "butter" diet. In the liver, cholesterol content was 2.7-fold lower in response to the "linseed" diet, whereas the concentration of HDL receptor (SR-BI) and the activities of HMGCoA reductase and cholesterol 7alpha-hydroxylase were 30 to 50% higher than with the "butter" diet. By contrast, the LDL receptor concentration did not vary with the diet. Females exhibited higher concentration of LDL (+24%), lower concentration of plasma triglycerides (-34%), total VLDL (-46%) and VLDL-cholesterol (-37%) and of biliary phospholipids (-19%). Besides, there was also an interaction between gender and diet: in males fed the "butter" diet, plasma triglycerides and VLDL concentration, were 2 to 4 fold higher than in the other groups. These data suggest that gene and/or metabolic regulations by fatty acids could interact with that of sex hormones and explain why males are more sensitive to dietary fatty acids.
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Affiliation(s)
- Anne Morise
- Laboratoire de Physiologie de la Nutrition-INRA, Université Paris-Sud, 91405 Orsay, France.
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Pakarinen MP, Pirinen P, Lauronen J, Raivio P, Kuusanmäki P, Halttunen J. Growth hormone selectively improves intestinal cholesterol absorption after jejunoileal autotransplantation in pigs. J Pediatr Surg 2004; 39:1220-5. [PMID: 15300531 DOI: 10.1016/j.jpedsurg.2004.04.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND/PURPOSE Small bowel transplantation impairs enteric function and causes malabsorption of cholesterol and bile acids. Growth hormone stimulates intestinal absorptive function. The authors hypothesized that long-term growth hormone therapy could improve absorption of bile acids and cholesterol after autotransplantation of the jejunoileum. METHODS Sixteen pigs with similar food, cholesterol, and fat intake underwent either sham laparotomy or a model of jejunoileal autotransplantation, including extrinsic autonomic denervation, lymphatic interruption, and in situ cold ischemia. Five randomly chosen autotransplanted animals received daily growth hormone treatment for 8 weeks. Serum lipids, absorption, and excretion of cholesterol, bile acids, and fat were determined after 8 weeks. Mucosal morphometrics, proliferation, and enzyme activities were determined. Plasma cholesterol precursors and plant sterols, respective markers of cholesterol synthesis and absorption, were measured after 2 and 8 weeks. RESULTS After jejunoileal autotransplantation, growth hormone treatment significantly increased body weight gain, cholesterol absorption efficiency from 45.1% to 62.1%, plasma campesterol to cholesterol proportions, and biliary secretion of cholesterol. With or without growth hormone treatment, autotransplantation significantly increased fecal bile acid excretion, plasma cholesterol precursors, fecal bacterially modified neutral sterols, mucosal thickness of the ileum (but not jejunum), and intestinal transit time when compared with sham-operated animals. Crypt cell proliferation, mucosal enzyme activities, and microvilli showed no differences between the groups. CONCLUSIONS These findings suggest that growth hormone treatment selectively improves cholesterol, but not bile acid absorption, after autotransplantation of the jejunoileum.
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Affiliation(s)
- Mikko P Pakarinen
- Department of Pediatric Surgery, Children's Hospital, Helsinki, Finland
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23
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Bento OP, Martins JM, Lança MJ, de Abreu MC, Viegas-Crespo AM, Freire JPB, Almeida JAA, Riottot M. Effects of ileo-rectal anastomosis on cholesterol metabolism in pigs fed either casein or extruded soya beans. Br J Nutr 2004; 91:689-98. [PMID: 15137920 DOI: 10.1079/bjn20041102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The importance of legume proteins in cholesterol metabolism has been recognised, but the hindgut contribution is still unclear. The present work was undertaken to address the role of the caecum-colon in cholesterol metabolism in intact (I) and ileo-rectal anastomosed (IRA) pigs fed with casein or extruded soyabean (ES) diets. Four groups of six growing pigs were assigned to the treatments (casein-I, casein-IRA, ES-I, ES-IRA) for 3 weeks. Plasma total cholesterol, LDL- and HDL-cholesterol were not modified by surgery or diet. In the liver, the ES diet significantly depressed non-esterified, esterified and total cholesterol. The treatments did not affect hepatic 3-hydroxy-3-methylglutaryl CoA reductase, cholesterol 7alpha-hydroxylase or sterol 27-hydroxylase activities. In the gallbladder bile of ES-fed pigs, total cholesterol was depressed while total bile acid concentration was increased. IRA and the ES diet markedly decreased the biliary bile acid microbial metabolites (namely hyodeoxycholic acid) and increased the primary bile acids (mainly hyocholic acid). The concentration of bile hydrophobic acids was decreased only by the ES diet. Faecal neutral sterol output was increased in ES-fed pigs, but the bile acid and the sum of neutral and acidic steroid outputs were not. Microbial transformation of neutral and acidic steroids was markedly reduced by IRA, especially in the ES-fed pigs. Thus, surgery and ES modulated the steroid profile but the caecum-colon did not seem to play a crucial role in determining cholesterolaemia in pigs.
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Affiliation(s)
- Ofélia P Bento
- Departamento de Zootecnia, Universidade de Evora, Apartado 94, 7002-554 Evora, Portugal
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24
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Blanchard G, Paragon BM, Sérougne C, Férézou J, Milliat F, Lutton C. Plasma lipids, lipoprotein composition and profile during induction and treatment of hepatic lipidosis in cats and the metabolic effect of one daily meal in healthy cats. J Anim Physiol Anim Nutr (Berl) 2004; 88:73-87. [PMID: 15059230 DOI: 10.1111/j.1439-0396.2003.00462.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Anorexia in obese cats may result in feline hepatic lipidosis (FHL). This study was designed to determine plasma lipids and lipoprotein profiles in queens at different stages during experimental induction of FHL (lean, obese, FHL), and after 10 weeks of treatment. Results were compared with those obtained from lean queens of same age fed the same diet but at a maintenance level, once a day. Hepatic lipidosis led to an increase in plasma triacylglycerol (TG), very low density lipoprotein (VLDL) and low density lipoprotein (LDL), and an enrichment of LDL with TG and of high density lipoprotein (HDL) with cholesterol, suggesting that VLDL secretion is enhanced, VLDL and LDL catabolism is lowered, and lipoprotein exchanges are impaired in FHL. This study also showed that cholesterolaemia is increased in cats fed at a dietary rhythm of one meal per day compared to ad libitum feeding.
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Affiliation(s)
- G Blanchard
- UP de Nutrition, Ecole Nationale Vétérinaire d'Alfort, Maisons Alfort, France.
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25
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Pakarinen MP, Pirinen P, Lauronen J, Raivio P, Kuusanmäki P, Halttunen J. Effects of transection and extrinsic denervation and a model of autotransplantation of the porcine jejunoileum on cholesterol biodynamics. J Pediatr Surg 2003; 38:1585-90. [PMID: 14614705 DOI: 10.1016/s0022-3468(03)00569-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND/PURPOSE Small bowel transplantation impairs enteric function, necessitating transection, extrinsic denervation, and ischemia-reperfusion of the small intestine. The authors investigated how each of these nonimmunologic insides of the transplantation procedure modulates biodynamics of cholesterol and absorption of lipids. METHODS Twenty-three pigs with similar food, cholesterol, and fat intake underwent sham laparotomy (group 1), transection (group 2), extrinsic jejunoileal denervation (group 3), or a model of autotransplantation, including extrinsic jejunoileal denervation with in situ ischemia-reperfusion (group 4). Serum lipids, absorption, and excretion of cholesterol, bile acids, and fat were determined after 8 weeks. Plasma cholesterol precursors and plant sterols, respective markers of cholesterol synthesis, and absorption, were measured after 2 and 8 weeks. RESULTS When compared with sham laparotomy and transection groups, denervation and autotransplantation significantly decreased weight gain and increased plasma cholesterol precursors and fecal excretion of bile acids. In relation to sham operated animals, transection alone modestly increased plasma plant sterols at 2 weeks and biliary secretion and mass absorption of cholesterol. The latter changes were not observed after denervation or autotransplantation, ie, fractional and total absorption of cholesterol were significantly decreased in autotransplanted pigs when compared with transected controls. As compared with all the other groups, autotransplantation significantly increased bacterial metabolites of neutral sterols in feces and net fecal elimination of cholesterol, mainly as bile acids. CONCLUSIONS Extrinsic autonomic denervation of the jejunoileum, with or without synchronous ischemia-reperfusion, results in increased cholesterol synthesis, bile acid malabsorption, and decreased weight gain. Cholesterol malabsorption may develop gradually after intestinal autotransplantation, and even a short period of ischemia further impairs absorptive function of the denervated jejunoileum, resulting in increased fecal elimination of cholesterol mainly as bile acids.
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Affiliation(s)
- Mikko P Pakarinen
- Department of Pediatric Surgery, Children's Hospital, University of Helsinki, Helsinki, Finland
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26
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García-Mediavilla V, Villares C, Culebras JM, Báyon JE, González-Gallego J. Effects of dietary beta-cyclodextrin in hypercholesterolaemic rats. PHARMACOLOGY & TOXICOLOGY 2003; 92:94-9. [PMID: 12747579 DOI: 10.1034/j.1600-0773.2003.920206.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Beta-cyclodextrin is a compound that forms inclusion complexes with a variety of molecules, specially bile acids and sterols. This study examines the effects of beta-cyclodextrin on cholesterol and bile acid metabolism in hypercholesterolaemic rats. Male Wistar rats were divided into 4 groups that received during 7 weeks: control diet, 2% cholesterol diet (A), A+2.5% beta-cyclodextrin (B) and A+5% beta-cyclodextrin (C). The cholesterol-rich diet induced hepatomegaly and fatty liver and significantly reduced cholesterol, bile acid and phospholipid secretion. Addition of beta-cyclodextrin normalised biliary lipid secretion. Moreover, when compared to A, beta-cyclodextrin significantly lowered plasma phospholipid concentration (B: -21%; C: -29%) and the liver free/total cholesterol molar ratio (B: -40%; C: -38%), increased bile acid faecal output (B: +17%; C: +62%) and enhanced cholesterol 7alpha-hydroxylase activity (B:+50%; C : +100%)and mRNA levels (B: + 14%; C: +29%). 5% beta-cyclodextrin also reduced plasma triglycerides concentration (-38%). However, ALT and AST activities were significantly increased (B: +140% and +280%; C: +72% and +135%) and there was a high incidence of cell necrosis with portal inflammatory cell infiltration. Addition of beta-cyclodextrin to a cholesterol-rich diet results in a triglyceride-lowering action, enhancement of bile acid synthesis and excretion, and normalization of biliary lipid secretion, but produces a marked hepatotoxic effect.
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Eckhardt ERM, Wang DQH, Donovan JM, Carey MC. Dietary sphingomyelin suppresses intestinal cholesterol absorption by decreasing thermodynamic activity of cholesterol monomers. Gastroenterology 2002; 122:948-56. [PMID: 11910347 DOI: 10.1053/gast.2002.32539] [Citation(s) in RCA: 142] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS In humans, cholesterol absorbed from the intestine contributes appreciably to serum cholesterol levels. We hypothesized that cholesterol thermodynamic activity (A(t)) would predict bioavailability of cholesterol monomers in intestinal content, and that natural dietary phospholipids exhibiting high affinity for cholesterol would reduce its absorption. METHODS Cholesterol A(t) was determined by measuring partitioning of monomeric cholesterol from aqueous solutions of taurocholate, cholesterol, and either milk sphingomyelin (MSM), dipalmitoyl phosphatidylcholine (DPPC), or egg yolk phosphatidylcholine (EYPC) into wafers of polymerized silicone. Cholesterol absorption from the same mixtures was tested with monolayers of Caco-2 cells. For in vivo absorption studies (employing male C57L/J mice), we used the fecal dual isotope method during dietary enrichment with MSM, DPPC, or EYPC at varying dose levels. RESULTS Cholesterol A(t) values were reduced significantly in MSM- and DPPC-containing systems compared with EYPC and correlated positively with reduced uptake and esterification of cholesterol by Caco-2 cells. Mice fed chow absorbed 31.4% +/- 6.9% (mean +/- SEM) cholesterol, whereas enrichment with MSM or DPPC led to dose-dependent decreases in cholesterol absorption; even at 0.1% MSM, cholesterol absorption was reduced by 20.4% +/- 15.4% (P < 0.05, n = 6). CONCLUSIONS Different phospholipids have distinct effects on micellar cholesterol A(t), which predicts cholesterol uptake by enterocytes in vitro as well as in vivo. Natural phospholipids with high affinity for cholesterol, as evidenced particularly by sphingomyelin, decrease A(t) and curtail intestinal cholesterol absorption.
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Affiliation(s)
- Erik R M Eckhardt
- Gastroenterology Division of Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
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Blanchard G, Paragon BM, Milliat F, Lutton C. Dietary L-carnitine supplementation in obese cats alters carnitine metabolism and decreases ketosis during fasting and induced hepatic lipidosis. J Nutr 2002; 132:204-10. [PMID: 11823579 DOI: 10.1093/jn/132.2.204] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This study was designed to determine whether dietary carnitine supplement could protect cats from ketosis and improve carnitine and lipid metabolism in experimental feline hepatic lipidosis (FHL). Lean spayed queens received a diet containing 40 (CL group, n = 7) or 1000 (CH group, n = 4) mg/kg of L-carnitine during obesity development. Plasma fatty acid, beta-hydroxybutyrate and carnitine, and liver and muscle carnitine concentrations were measured during experimental induction of FHL and after treatment. In control cats (CL group), fasting and FHL increased the plasma concentrations of fatty acids two- to threefold (P < 0.0001) and beta-hydroxybutyrate > 10-fold (from a basal 0.22 +/- 0.03 to 1.70 +/- 0.73 after 3 wk fasting and 3.13 +/- 0.49 mmol/L during FHL). In carnitine-supplemented cats, these variables increased significantly (P < 0.0001) only during FHL (beta-hydroxybutyrate, 1.42 +/- 0.17 mmol/L). L-Carnitine supplementation significantly increased plasma, muscle and liver carnitine concentrations. Liver carnitine concentration increased dramatically from the obese state to FHL in nonsupplemented cats, but not in supplemented cats, which suggests de novo synthesis of carnitine from endogenous amino acids in control cats and reversible storage in supplemented cats. These results demonstrate the protective effect of a dietary L-carnitine supplement against fasting ketosis during obesity induction. Increasing the L-carnitine level of diets in cats with low energy requirements, such as after neutering, and a high risk of obesity could therefore be recommended.
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Affiliation(s)
- Géraldine Blanchard
- UP de Nutrition, Ecole Nationale Vétérinaire d'Alfort, 94704 Maisons Alfort, France.
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Abstract
The vasculature of a tumour provides the most effective route by which neoplastic cells may be reached and eradicated by drugs. The fact that a tumour's vasculature is relatively more permeable than healthy host tissue should enable selective delivery of drugs to tumour tissue. Such delivery is relevant to carrier-mediated delivery of genetic medicine to tumours. This review discusses the potential of delivering therapeutic oligonucleotides (ONs) to tumours using cationic liposomes and cyclodextrins (CyDs), and the major hindrances posed by the tumour itself on such delivery. Cationic liposomes are generally 100-200 nm in diameter, whereas CyDs typically span 1.5 nm across. Cationic liposomes have been used for the introduction of nucleic acids into mammalian cells for more than a decade. CyD molecules are routinely used as agents that engender cholesterol efflux from lipid-laden cells, thus having an efficacious potential in the management of atherosclerosis. A recent trend is to employ these oligosaccharide molecules for delivering nucleic acids in cells both in-vitro and in-vivo. Comparisons are made with other ON delivery agents, such as porphyrin derivatives (< 1 nm), branched chain dendrimers (approximately 10 nm), polyethylenimine polymers (approximately 10 nm), nanoparticles (20-1,000 nm) and microspheres (> 1 microm), in the context of delivery to solid tumours. A discourse on how the chemical and physical properties of these carriers may affect the uptake of ONs into cells, particularly in-vivo, forms a major basis of this review.
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Affiliation(s)
- Crispin R Dass
- Johnson & Johnson Research, Strawberry Hills, Australia.
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Wray-Cahen D, Caperna TJ, Steele NC. Methyl-beta-cyclodextrin: an alternative carrier for intravenous infusion of palmitate during tracer studies in swine (Sus scrofa domestica). Comp Biochem Physiol A Mol Integr Physiol 2001; 130:55-65. [PMID: 11672683 DOI: 10.1016/s1095-6433(01)00369-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Fatty acid-free albumin has been the standard carrier for intravenous infusion of fatty acids to study in vivo lipid metabolism. However, subjects can have adverse reactions to infusion of albumin. We sought an alternative to albumin as a carrier for intravenous infusion of fatty acids, using the pig as a model. Cyclodextrins are naturally occurring water-soluble molecules that can serve as carriers for lipid-soluble compounds. 13C-palmitate was complexed to either 20% methyl-beta-cyclodextrin, 20% 2-hydroxypropyl-beta-cyclodextrin, or 5% porcine albumin (isotopic purity of infusates: 99.22+/-0.06%). 13C-palmitate-albumin was infused under fed conditions and 13C-palmitate-methyl-beta-cyclodextrin was infused under fasted and fed conditions in 50-kg pigs. Palmitate remained in solution at 4 degrees C in methyl-beta-cyclodextrin, but precipitated at 25-30 degrees C in 2-hydroxypropyl-beta-cyclodextrin. Pigs infused with 13C-palmitate-methyl-beta-cyclodextrin maintained normal body temperature and appetite; those infused with 13C-palmitate-albumin became anorexic and exhibited other negative side effects to albumin. Palmitate oxidation rates under fed conditions were similar using either 13C-palmitate-methyl-beta-cyclodextrin or 13C-palmitate-albumin complexes. Fasting increased 13C-palmitate-methyl-beta-cyclodextrin oxidation by approximately eight-fold. These data suggest that methyl-beta-cyclodextrin may be a suitable substitute for albumin in fatty acid metabolism studies in swine.
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Affiliation(s)
- D Wray-Cahen
- USDA-ARS, Livestock and Poultry Science Institute, Growth Biology Laboratory, Beltsville, MD 20705, USA.
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31
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Souidi M, Combettes-Souverain M, Milliat F, Eckhardt ER, Audas O, Dubrac S, Parquet M, Férézou J, Lutton C. Hamsters predisposed to sucrose-induced cholesterol gallstones (LPN strain) are more resistant to excess dietary cholesterol than hamsters that are not sensitive to cholelithiasis induction. J Nutr 2001; 131:1803-11. [PMID: 11385071 DOI: 10.1093/jn/131.6.1803] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We compared the effects of cholesterol feeding in male hamsters from two strains with different propensities to sucrose-induced cholelithiasis; Laboratoire de Physiologie de la Nutrition (LPN) hamsters are predisposed to developing biliary cholesterol gallstones, whereas Janvier (JAN) hamsters are not. When fed a basal control diet, LPN hamsters had a lower cholesterolemia (-21%, P = 0.01) than JAN hamsters, and a higher activity of 3-hydroxy-3-methyl glutaryl coenzyme A reductase in liver (+148%, P = 0.018) and intestine (+281%, P < 0.0001). After feeding the same diet enriched with 0.3% cholesterol for 5 wk, cholesterolemia increased more dramatically in JAN hamsters (+235%, P < 0.001) than in LPN hamsters (+108%, P < 0.001), as did the liver concentration of cholesterol, which reached 152.30 +/- 13.00 and 44.41 +/- 9.06 micromol/g, respectively. Only JAN hamsters displayed hepatomegaly, with an increased cholesterol saturation index of the gallbladder bile (+100%, P < 0.01), due to the cholesterol challenge. In liver, cholesterol feeding reduced cholesterol 7alpha-hydroxylase activity and mRNA level, and stimulated sterol 27-hydroxylase and oxysterol 7alpha-hydroxylase activities. Hepatic levels of LDL receptor decreased by approximately 60% in both strains, whereas HDL receptor scavenger class B type 1 (SR-BI) levels were unaffected by dietary cholesterol. The greater resistance of LPN hamsters to the hypercholesterolemic diet can be explained by a lower capacity to store cholesterol in the liver and greater efficiency in reducing the activity of 3-hydroxy-3-methyl glutaryl coenzyme A reductase in response to cholesterol feeding [from 11263 to 261 pmol/(min x organ) in LPN hamsters and from 4530 to 694 pmol/(min x organ) in JAN hamsters]. These results highlight the usefulness of this two-strain model, which offers some analogy with the inverse association between the predisposition to cholelithiasis and the risk of atherosclerosis in humans.
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Affiliation(s)
- M Souidi
- Laboratoire de Physiologie de la Nutrition-INRA, Université Paris XI, F-91405 Orsay Cedex, France
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Férézou J, Combettes-Souverain M, Souidi M, Smith JL, Boehler N, Milliat F, Eckhardt E, Blanchard G, Riottot M, Sérougne C, Lutton C. Cholesterol, bile acid, and lipoprotein metabolism in two strains of hamster, one resistant, the other sensitive (LPN) to sucrose-induced cholelithiasis. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)32366-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Smith JL, Roach PD, Wittenberg LN, Riottot M, Pillay SP, Nestel PJ, Nathanson LK. Effects of simvastatin on hepatic cholesterol metabolism, bile lithogenicity and bile acid hydrophobicity in patients with gallstones. J Gastroenterol Hepatol 2000; 15:871-9. [PMID: 11022827 DOI: 10.1046/j.1440-1746.2000.02231.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIMS There is limited information available on the effects of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors on hepatic and biliary cholesterol metabolism in patients with gallstones. The aims of this study were to determine the effect of simvastatin on the regulatory elements of cholesterol metabolism that determine the concentrations of cholesterol in plasma and bile. METHODS Thirty-one gallstone patients were enrolled in the study; 17 were treated with 20 mg simvastatin daily for 3 weeks prior to cholecystectomy and 14 served as controls. Samples of blood, liver, gall-bladder bile and bile from the common bile duct (CBD) were collected and analysed. RESULTS The plasma cholesterol (-30%), triacylglycerol (-23%) and low-density lipoprotein (LDL) cholesterol (-42%) concentrations were significantly lowered by simvastatin treatment, as was the plasma lathosterol: cholesterol (-70%), which reflects whole-body cholesterol synthesis. Despite these changes, the hepatic LDL receptor protein and LDL receptor activity in circulating mononuclear cells were similar in both groups. There were no differences in the plasma phytosterol: cholesterol, which reflects the intestinal cholesterol absorption capacity or in the activity of hepatic acyl-coenzyme A: cholesterol acyltransferase. There were however, lower cholesterol concentrations in CBD (-68%) and gall bladder (-41%) bile, and decreased lithogenic (-47%) and bile acid hydrophobicity (-22%) indices of CBD bile in the simvastatin group. CONCLUSIONS These data indicate that simvastatin reduced plasma and biliary cholesterol levels primarily by reducing cholesterol synthesis. The reduction in CBD bile lithogenicity and bile acid hydrophobicity by simvastatin suggests that this agent may be useful for people who have early stages of cholesterol gallstone development and in whom a choleretic effect is required.
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Affiliation(s)
- J L Smith
- Department of Surgery, The University of Queensland, Royal Brisbane Hospital, Australia.
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Dass CR, Jessup W. Apolipoprotein A-I, cyclodextrins and liposomes as potential drugs for the reversal of atherosclerosis. A review. J Pharm Pharmacol 2000; 52:731-61. [PMID: 10933125 DOI: 10.1211/0022357001774606] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Several studies have revealed that high-density lipoprotein (HDL) is the most reliable predictor for susceptibility to cardiovascular disease. Since apolipoprotein A-I (apoA-I) is the major protein of HDL, it is worthwhile evaluating the potential of this protein to reduce the lipid burden of lesions observed in the clinic. Indeed, apoA-I is used extensively in cell culture to induce cholesterol efflux. However, while there is a large body of data emanating from in-vitro and cell-culture studies with apoA-I, little animal data and scant clinical trials examining the potential of this apolipoprotein to induce cholesterol (and other lipid) efflux exists. Importantly, the effects of oxysterols, such as 7-ketocholesterol (7KC), on cholesterol and other lipid efflux by apoA-I needs to be investigated in any attempt to utilise apoA-I as an agent to stimulate efflux of lipids. Lessons may be learnt from studies with other lipid acceptors such as cyclodextrins and phospholipid vesicles (PLVs, liposomes), by combination with other effluxing agents, by remodelling the protein structure of the apolipoprotein, or by altering the composition of the lipoprotein intended for administration in-vivo. Akin to any other drug, the usage of this apolipoprotein in a therapeutic context has to follow the traditional sequence of events, namely an evaluation of the biodistribution, safety and dose-response of the protein in animal trials in advance of clinical trials. Mass production of the apolipoprotein is now a simple process due to the advent of recombinant DNA technology. This review also considers the potential of cyclodextrins and PLVs for use in inducing reverse cholesterol transport in-vivo. Finally, the potential of cyclodextrins as delivery agents for nucleic acid-based constructs such as oligonucleotides and plasmids is discussed.
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Affiliation(s)
- C R Dass
- Johnson and Johnson Research, Strawberry Hills, Australia.
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Dass CR. Apolipoprotein A-I, phospholipid vesicles, and cyclodextrins as potential anti-atherosclerotic drugs: delivery, pharmacokinetics, and efficacy. Drug Deliv 2000; 7:161-82. [PMID: 10989917 DOI: 10.1080/10717540050120205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
High-density lipoprotein (HDL) is a reliable predictor for susceptibility to cardiovascular disease. Since apolipoprotein A-I (apoA-I) is the major protein of HDL, it is worthwhile to evaluate the potential of this protein to reduce the lipid burden of lesions observed in the clinic. While a large body of data emanates from in vitro and cell culture studies with apoA-I, few animal and lesser clinical trials examining the potential of this apolipoprotein to induce cholesterol (and other lipid) efflux exist. Lessons may be learned from studies with other lipid acceptors such as phospholipid vesicles (PLVs, liposomes) and cyclodextrins (CDs). Additionally, the combination of apoA-I with other effluxing agents, alteration of the composition of the lipoprotein, or a remodeling of the protein structure of the apolipoprotein to be administered in vivo may result in increased efficacy. The usage of this apolipoprotein in a therapeutic context has to follow the conventional sequence of events: an evaluation of the biodistribution, safety, and dose-response of the protein in animal trials before clinical trials. The review also considers the potential of cyclodextrins and PLVs to induce reverse cholesterol transport in vivo and discusses the potential of CDs as delivery agents for genetic constructs, such as plasmids and oligonucleotides.
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Affiliation(s)
- C R Dass
- Johnson and Johnson Research, Strawberry Hills, Australia.
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Abstract
Oxygenated derivatives of cholesterol (oxysterols) present a remarkably diverse profile of biological activities, including effects on sphingolipid metabolism, platelet aggregation, apoptosis, and protein prenylation. The most notable oxysterol activities center around the regulation of cholesterol homeostasis, which appears to be controlled in part by a complex series of interactions of oxysterol ligands with various receptors, such as the oxysterol binding protein, the cellular nucleic acid binding protein, the sterol regulatory element binding protein, the LXR nuclear orphan receptors, and the low-density lipoprotein receptor. Identification of the endogenous oxysterol ligands and elucidation of their enzymatic origins are topics of active investigation. Except for 24, 25-epoxysterols, most oxysterols arise from cholesterol by autoxidation or by specific microsomal or mitochondrial oxidations, usually involving cytochrome P-450 species. Oxysterols are variously metabolized to esters, bile acids, steroid hormones, cholesterol, or other sterols through pathways that may differ according to the type of cell and mode of experimentation (in vitro, in vivo, cell culture). Reliable measurements of oxysterol levels and activities are hampered by low physiological concentrations (approximately 0.01-0.1 microM plasma) relative to cholesterol (approximately 5,000 microM) and by the susceptibility of cholesterol to autoxidation, which produces artifactual oxysterols that may also have potent activities. Reports describing the occurrence and levels of oxysterols in plasma, low-density lipoproteins, various tissues, and food products include many unrealistic data resulting from inattention to autoxidation and to limitations of the analytical methodology. Because of the widespread lack of appreciation for the technical difficulties involved in oxysterol research, a rigorous evaluation of the chromatographic and spectroscopic methods used in the isolation, characterization, and quantitation of oxysterols has been included. This review comprises a detailed and critical assessment of current knowledge regarding the formation, occurrence, metabolism, regulatory properties, and other activities of oxysterols in mammalian systems.
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Affiliation(s)
- G J Schroepfer
- Departments of Biochemistry, Rice University, Houston, Texas, USA.
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Boehler N, Riottot M, Férézou J, Souidi M, Milliat F, Sérougne C, Smith JL, Lutton C. Antilithiasic effect of β-cyclodextrin in LPN hamster: comparison with cholestyramine. J Lipid Res 1999. [DOI: 10.1016/s0022-2275(20)32152-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Trautwein EA, Forgbert K, Rieckhoff D, Erbersdobler HF. Impact of beta-cyclodextrin and resistant starch on bile acid metabolism and fecal steroid excretion in regard to their hypolipidemic action in hamsters. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1437:1-12. [PMID: 9931405 DOI: 10.1016/s0005-2760(98)00174-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To examine the impact on bile acid metabolism and fecal steroid excretion as a mechanism involved in the lipid-lowering action of beta-cyclodextrin and resistant starch in comparison to cholestyramine, male golden Syrian hamsters were fed 0% (control), 8% or 12% of beta-cyclodextrin or resistant starch or 1% cholestyramine. Resistant starch, beta-cyclodextrin and cholestyramine significantly lowered plasma total cholesterol and triacylglycerol concentrations compared to control. Distinct changes in the bile acid profile of gallbladder bile were caused by resistant starch, beta-cyclodextrin and cholestyramine. While cholestyramine significantly reduced chenodeoxycholate independently of its taurine-glycine conjugation, beta-cyclodextrin and resistant starch decreased especially the percentage of taurochenodeoxycholate by -75% and -44%, respectively. As a result, the cholate:chenodeoxycholate ratio was significantly increased by 100% with beta-cyclodextrin and by 550% with cholestyramine while resistant starch revealed no effect on this ratio. beta-Cyclodextrin and resistant starch, not cholestyramine, significantly increased the glycine:taurine conjugation ratio demonstrating the predominance of glycine conjugated bile acids. Daily fecal excretion of bile acids was 4-times higher with 8% beta-cyclodextrin and 19-times with 1% cholestyramine compared to control. beta-Cyclodextrin and cholestyramine also induced a 2-fold increase in fecal neutral sterol excretion, demonstrating the sterol binding capacity of these two compounds. Resistant starch had only a modest effect on fecal bile acid excretion (80% increase) and no effect on excretion of neutral sterols, suggesting a weak interaction with intestinal steroid absorption. These data demonstrate the lipid-lowering potential of beta-cyclodextrin and resistant starch. An impaired reabsorption of circulating bile acids and intestinal cholesterol absorption leading to an increase in fecal bile acid and neutral sterol excretion is most likely the primary mechanism responsible for the lipid-lowering action of beta-cyclodextrin. In contrast, other mechanisms involving the alterations in the biliary bile acid profile or repressed hepatic lipogenesis, e.g., VLDL production, appear to be involved in the hypolipidemic effect of resistant starch.
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Affiliation(s)
- E A Trautwein
- University of Kiel, Institute of Human Nutrition and Food Science, Düsternbrooker Weg 17, 24105, Kiel, Germany.
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Abstract
Cultured rat sympathetic neurons derived from postnatal rat superior cervical ganglia (SCG) were used to compare the neurotoxicity of several cholesterol oxides. The cholesterol oxides tested included: 7-beta-OH-, 7-keto-, 19-OH-, 22(R)-OH-, 22(S)-OH-, and 25-OH-cholesterol. These agents caused an acute as well as a delayed toxicity in sympathetic neurons with 25-OH-cholesterol appearing to be the most toxic. A time-dependent experiment indicated that 25-OH-cholesterol at 4 microg/ml (10 microM) was able to kill 50% of the cells in 36 h. Morphological studies indicate that most of the cells do not exhibit a structural change similar to that observed in neuronal programmed cell death. Whole-cell patch clamp recording of untreated controls and 25-OH-cholesterol (2 microg/ml)-treated cells indicated that this toxicity was not accompanied by significant changes in voltage-dependent calcium channel activity. A number of pharmacological agents including ethylene glycolbis (beta-aminoethyl ether) N,N,N',N'-tetraacetic acid (EGTA), cycloheximide, KCl, vitamin E, and methyl-beta-cyclodextrin were able to prevent the 25-OH-cholesterol-induced cell death to various degrees. These results suggest that, in addition to causing pathological changes in cells directly involved in atherosclerosis, cholesterol oxides may induce neurotoxicity in sympathetic neurons.
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Affiliation(s)
- J Y Chang
- Department of Anatomy, University of Arkansas for Medical Sciences, Little Rock 72205, USA.
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Abstract
Cultured rat cerebellar granule cells were used to determine the potential neurotoxicity of cholesterol oxides. The cholesterol oxides tested included: 7-beta-OH-, 7-keto-, 19-OH-, 22(R)-OH-, 22(S)-OH- and 25-OH- cholesterol. Among them, 7-beta-OH- and 7-keto-cholesterol were the most efficacious in causing neuronal death such that 20 microg/ml (50 microM) of these agents killed more than 80% of cells in 2 days. 7-beta-OH-cholesterol at this concentration killed 50% of cells in approximately 7 h. A number of pharmacological agents were tested for their abilities to prevent neuronal death induced by cholesterol oxides. Among them, aurintricarboxylic acid, vitamin E and methyl-beta-cyclodextrin were able to prevent cholesterol oxide-induced neurotoxicity in a dose-dependent manner. These results suggest that, in addition to causing pathological changes in cells directly involved in atherosclerosis, cholesterol oxides may induce toxicity in neurons of the central nervous system.
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Affiliation(s)
- J Y Chang
- Department of Anatomy, University of Arkansas for Medical Sciences, Little Rock 72205, USA
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Abstract
Despite limitations, animal models continue to provide insight into the etiology of atherosclerosis. Hamsters, guinea-pigs, and domesticated pigs are being used more frequently to address the biochemical bases for the effects of dietary lipids on cholesterol metabolism.
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Abstract
PURPOSE By using nerve growth factor-differentiated PC12 cells as a model for sympathetic neurons, we have recently shown that cholesterol oxides are toxic to cells of neural origin. Since lipid metabolism is known to be involved in some pathological conditions associated with the visual system, we sought to extend this line of research by studying the potential cytotoxicity of cholesterol oxides on primary cultures derived from neuroretinas. METHODS Dissociated cultures derived from neuroretinas of 1-day-old Sprague-Dawley rats were used in this series of studies. Immunohistochemical staining was used to identify neuronal and glial cell types in these cultures. MTT assay was used to determine the cytotoxicity of cholesterol oxides, including 7-beta-OH-, 7-keto-, 19-OH-, 22(R)-OH-, 22(S)-OH- and 25-OH-cholesterol. RESULTS Among the cholesterol oxides tested, 7-beta-OH- and 7-keto-cholesterol were the most effective in causing cell death, such that 20 micrograms/ml (50 microM) of these agents killed approximately 80% of cells in 3 days. A time-dependent experiment indicated that 10 micrograms/ml of 7-beta-cholesterol was able to kill 50% of cells in approximately 5 h. A number of pharmacological agents were tested for their ability to prevent cell death induced by cholesterol oxides. Among them, vitamin E and methyl-beta-cyclodextrin were able to prevent cholesterol oxide-induced cell death in a dose-dependent manner. CONCLUSIONS These results suggest that, in addition to causing pathological changes in cells directly involved in atherosclerosis, cholesterol oxides may be toxic to cells derived from neuroretinas.
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Affiliation(s)
- J Y Chang
- Department of Anatomy, University of Arkansas for Medical Sciences, Little Rock 72205, USA.
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