1
|
Hirayama S, Nagasaka H, Honda A, Komatsu H, Kodama T, Inui A, Morioka I, Kaji S, Ueno T, Ihara K, Yagi M, Kizaki Z, Bessho K, Kondou H, Yorifuji T, Tsukahara H, Iijima K, Miida T. Cholesterol Metabolism Is Enhanced in the Liver and Brain of Children With Citrin Deficiency. J Clin Endocrinol Metab 2018; 103:2488-2497. [PMID: 29659898 DOI: 10.1210/jc.2017-02664] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 04/02/2018] [Indexed: 02/07/2023]
Abstract
CONTEXT Citrin-deficient infants present neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD), which resolves at 12 months. Thereafter, they have normal liver function associated with hypercholesterolemia, and a preference for lipid-rich carbohydrate-restricted diets. However, some develop adult-onset type II citrullinemia, which is associated with metabolic abnormalities. OBJECTIVES To identify the causes of hypercholesterolemia in citrin-deficient children post-NICCD. DESIGN AND SETTING We determined the concentrations of sterol markers of cholesterol synthesis, absorption, and catabolism by liquid chromatography-electrospray ionization-tandem mass spectrometry and evaluated serum lipoprotein profiles. SUBJECTS Twenty citrin-deficient children aged 5 to 13 years and 37 age-matched healthy children. INTERVENTION None. MAIN OUTCOME MEASURES Relationship between serum lipoproteins and sterol markers of cholesterol metabolism. RESULTS The citrin-deficient group had a significantly higher high-density lipoprotein cholesterol (HDL-C) concentration than did the control group (78 ± 11 mg/dL vs 62 ± 14 mg/dL, P < 0.001), whereas the two groups had similar low-density lipoprotein cholesterol and triglyceride concentrations. The concentrations of markers of cholesterol synthesis (lathosterol and 7-dehydrocholesterol) and bile acids synthesis (7α-hydroxycholesterol and 27-hydroxycholesterol) were 1.5- to 2.8-fold and 1.5- to 3.9-fold, respectively, higher in the citrin-deficient group than in the control group. The concentration of 24S-hydroxycholesterol, a marker of cholesterol catabolism in the brain, was 2.5-fold higher in the citrin-deficient group. In both groups, the HDL-C concentration was significantly positively correlated with that of 27-hydroxycholesterol, the first product of the alternative bile acid synthesis pathway. CONCLUSIONS HDL-C and sterol marker concentrations are elevated in citrin-deficient children post-NICCD. Moreover, cholesterol synthesis and elimination are markedly enhanced in the liver and brain of citrin-deficient children.
Collapse
Affiliation(s)
- Satoshi Hirayama
- Department of Clinical Laboratory Medicine, Juntendo University School of Medicine, Tokyo, Japan
| | - Hironori Nagasaka
- Department of Pediatrics, Takarazuka City Hospital, Takarazuka, Japan
| | - Akira Honda
- Joint Research Center and Division of Gastroenterology, Tokyo Medical University Ibaraki Medical Center, Ibaraki, Japan
| | - Haruki Komatsu
- Department of Pediatrics, Toho University Sakura Medical Center, Sakura, Japan
| | - Takahiro Kodama
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Ayano Inui
- Department of Pediatric Hepatology and Gastroenterology, Saiseikai Yokohamashi Tobu Hospital, Yokohama, Japan
| | - Ichiro Morioka
- Department of Pediatrics and Child Health, Nihon University School of Medicine, Tokyo, Japan
| | - Shunsaku Kaji
- Department of Pediatrics, Tsuyama-Chuo Hospital, Okayama, Japan
| | - Tsuyoshi Ueno
- Department of Clinical Laboratory Medicine, Juntendo University School of Medicine, Tokyo, Japan
| | - Kenji Ihara
- Department of Pediatrics, Kyushu University Graduate School of Medical Science, Fukuoka, Japan
- Department of Pediatrics, Oita University, Faculty of Medicine, Yufu, Japan
| | - Mariko Yagi
- Department of Pediatrics, Nikoniko House Medical & Welfare Center, Kobe, Japan
| | - Zenro Kizaki
- Department of Pediatrics, Japanese Red Cross Kyoto Daiichi Hospital, Kyoto, Japan
| | - Kazuhiko Bessho
- Department of Pediatrics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Hiroki Kondou
- Department of Pediatrics, Kindai University Nara Hospital, Nara, Japan
| | - Tohru Yorifuji
- Division of Pediatric Endocrinology and Metabolism, Children's Medical Center, Osaka City General Hospital, Osaka, Japan
| | - Hirokazu Tsukahara
- Department of Pediatrics, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takashi Miida
- Department of Clinical Laboratory Medicine, Juntendo University School of Medicine, Tokyo, Japan
- Department of Clinical Laboratory Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan
| |
Collapse
|
2
|
Cholesterol oversynthesis markers define familial combined hyperlipidemia versus other genetic hypercholesterolemias independently of body weight. J Nutr Biochem 2018; 53:48-57. [DOI: 10.1016/j.jnutbio.2017.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 09/07/2017] [Accepted: 10/14/2017] [Indexed: 12/31/2022]
|
3
|
Fliesler SJ, Peachey NS, Herron J, Hines KM, Weinstock NI, Ramachandra Rao S, Xu L. Prevention of Retinal Degeneration in a Rat Model of Smith-Lemli-Opitz Syndrome. Sci Rep 2018; 8:1286. [PMID: 29352199 PMCID: PMC5775248 DOI: 10.1038/s41598-018-19592-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 01/04/2018] [Indexed: 12/20/2022] Open
Abstract
Smith-Lemli-Opitz Syndrome (SLOS) is a recessive human disease caused by defective cholesterol (CHOL) synthesis at the level of DHCR7 (7-dehydrocholesterol reductase), which normally catalyzes the conversion of 7-dehydrocholesterol (7DHC) to CHOL. Formation and abnormal accumulation of 7DHC and 7DHC-derived oxysterols occur in SLOS patients and in rats treated with the DHCR7 inhibitor AY9944. The rat SLOS model exhibits progressive and irreversible retinal dysfunction and degeneration, which is only partially ameliorated by dietary CHOL supplementation. We hypothesized that 7DHC-derived oxysterols are causally involved in this retinal degeneration, and that blocking or reducing their formation should minimize the phenotype. Here, using the SLOS rat model, we demonstrate that combined dietary supplementation with CHOL plus antioxidants (vitamins E and C, plus sodium selenite) provides better outcomes than dietary CHOL supplementation alone with regard to preservation of retinal structure and function and lowering 7DHC-derived oxysterol formation. These proof-of-principle findings provide a translational, pre-clinical framework for designing clinical trials using CHOL-antioxidant combination therapy as an improved therapeutic intervention over the current standard of care for the treatment of SLOS.
Collapse
Affiliation(s)
- Steven J Fliesler
- Research Service, VA Western New York Healthcare System, Buffalo, NY, USA. .,Departments of Ophthalmology and Biochemistry, and Neuroscience Program, Jacobs School of Medicine & Biomedical Sciences, University at Buffalo- The State University of New York (SUNY), Buffalo, NY, USA. .,SUNY Eye Institute, Buffalo, NY, USA.
| | - Neal S Peachey
- Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA.,Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH, USA.,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA
| | - Josi Herron
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA, USA
| | - Kelly M Hines
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA, USA
| | - Nadav I Weinstock
- Hunter James Kelly Research Institute, Jacobs School of Medicine & Biomedical Sciences, University at Buffalo- The State University of New York (SUNY), Buffalo, NY, USA
| | - Sriganesh Ramachandra Rao
- Research Service, VA Western New York Healthcare System, Buffalo, NY, USA.,Departments of Ophthalmology and Biochemistry, and Neuroscience Program, Jacobs School of Medicine & Biomedical Sciences, University at Buffalo- The State University of New York (SUNY), Buffalo, NY, USA.,SUNY Eye Institute, Buffalo, NY, USA
| | - Libin Xu
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA, USA.
| |
Collapse
|
4
|
Zhang X, Li B, Luo X, Zhao W, Jiang J, Zhang C, Gao M, Chen X, Dong Y. Biodegradable Amino-Ester Nanomaterials for Cas9 mRNA Delivery in Vitro and in Vivo. ACS APPLIED MATERIALS & INTERFACES 2017; 9:25481-25487. [PMID: 28685575 PMCID: PMC5896755 DOI: 10.1021/acsami.7b08163] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Efficient and safe delivery of the CRISPR/Cas system is one of the key challenges for genome-editing applications in humans. Herein, we designed and synthesized a series of biodegradable lipidlike compounds containing ester groups for the delivery of mRNA-encoding Cas9. Two lead materials, termed N-methyl-1,3-propanediamine (MPA)-A and MPA-Ab, showed a tunable rate of biodegradation. MPA-A with linear ester chains was degraded dramatically faster than MPA-Ab with branched ester chains in the presence of esterase or in wild-type mice. Most importantly, MPA-A and MPA-Ab demonstrated efficient delivery of Cas9 mRNA both in vitro and in vivo. Consequently, these biodegradable lipidlike nanomaterials merit further development as genome-editing delivery tools for biological and therapeutic applications.
Collapse
Affiliation(s)
- Xinfu Zhang
- Division of Pharmaceutics & Pharmaceutical Chemistry, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, United States
| | - Bin Li
- Division of Pharmaceutics & Pharmaceutical Chemistry, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, United States
| | - Xiao Luo
- Division of Pharmaceutics & Pharmaceutical Chemistry, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, United States
| | - Weiyu Zhao
- Division of Pharmaceutics & Pharmaceutical Chemistry, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, United States
| | - Justin Jiang
- Division of Pharmaceutics & Pharmaceutical Chemistry, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, United States
| | - Chengxiang Zhang
- Division of Pharmaceutics & Pharmaceutical Chemistry, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, United States
| | - Min Gao
- LCI Characterization Facility, Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, United States
| | - Xiaofang Chen
- Division of Pharmaceutics & Pharmaceutical Chemistry, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, United States
| | - Yizhou Dong
- Division of Pharmaceutics & Pharmaceutical Chemistry, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, United States
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio 43210, United States
- The Center for Clinical and Translational Science, The Ohio State University, Columbus, Ohio 43210, United States
- The Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210, United States
- James Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210, United States
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio 43210, United States
- Department of Radiation Oncology, The Ohio State University, Columbus, Ohio 43210, United States
| |
Collapse
|
5
|
Stellaard F, von Bergmann K, Sudhop T, Lütjohann D. The value of surrogate markers to monitor cholesterol absorption, synthesis and bioconversion to bile acids under lipid lowering therapies. J Steroid Biochem Mol Biol 2017; 169:111-122. [PMID: 27060336 DOI: 10.1016/j.jsbmb.2016.03.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 03/21/2016] [Accepted: 03/22/2016] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Regulation of cholesterol (Chol) homeostasis is controlled by three main fluxes, i.e. intestinal absorption, de novo synthesis (ChS) and catabolism, predominantly as bile acid synthesis (BAS). High serum total Chol and LDL-Chol concentrations in particular are considered risk factors and markers for the development of atherosclerosis. Pharmaceutical treatments to lower serum Chol have focused on reducing absorption or ChS and increasing BAS. Monitoring of these three parameters is complex involving isotope techniques, cholesterol balance experiments and advanced mass spectrometry based analysis methods. Surrogate markers were explored that require only one single fasting blood sample collection. These markers were validated in specific, mostly physiological conditions and during statin treatment to inhibit ChS. They were also applied under cholesterol absorption restriction, but were not validated in this condition. We retrospectively evaluated the use of serum campesterol (Camp), sitosterol (Sit) and cholestanol (Cholol) as markers for cholesterol absorption, lathosterol (Lath) as marker for ChS and 7α-hydroxycholesterol (7α-OH-Ch) and 27-hydroxycholesterol (27-OH-Ch) as markers for BAS under conditions of Chol absorption restriction. Additionally, their values were corrected for Chol concentration (R_sterol or oxysterols). METHODS Thirty-seven healthy male omnivore subjects were studied under treatments with placebo (PLAC), ezetimibe (EZE) to inhibit cholesterol absorption, simvastatin (SIMVA) to reduce cholesterol synthesis and a combination of both (EZE+SIMVA). Results were compared to those obtained in 18 pure vegetarian subjects (vegans) whose dietary Chol intake is extremely low. Relative or fractional Chol absorption (FrChA) was measured with the continuous feeding stable isotope procedure, ChS and BAS with the cholesterol balance method. The daily Chol intake (DICh) was inventoried and the daily Chol absorption (DACh) calculated. RESULTS Monitoring cholesterol absorption, R_Camp, R_Sit and R_Cholol responded sensitively to changes in FrChA. R_Camp correlated well with FrChA in all omnivore treatment groups and in the vegan group. R_Camp confirmed reduced FrChA under EZE treatment and reduced DACh in the vegan subjects. R_Sit and R_Cholol did not accurately reflect FrChA or DACh in all situations. Monitoring endogenous cholesterol synthesis, R_Lath correlated with ChS in the vegan group, but in none of the omnivore treatment groups. R_Lath confirmed increased ChS under EZE treatment and was reduced under SIMVA treatment, while ChS was not. An increased ChS under EZE+SIMVA treatment could not be confirmed with R_Lath. R_Lath responded very insensitively to a change in ChS. Monitoring BAS, R_7α-OH-Ch but not R_27-OH-Ch correlated with BAS during PLAC, EZE and SIMVA treatments. In line with BAS, R_7α-OH-Ch did not differ in any of the omnivore treatment groups. R_7α-OH-Ch responded insensitively to a change in BAS. CONCLUSIONS Under Chol absorption restriction, serum R_Camp is a sensitive and valid marker to monitor FrChA in a population with a normal DICh. Also, major changes in DACh can be detected in vegans. Serum R_Lath does not reflect ChS measured with the cholesterol balance method during EZE treatment. This result initiates the question whether the measured ChS reflects pure de novo synthesis. Serum R_7α-OH-Ch appears to be a valid but insensitive marker for BAS.
Collapse
Affiliation(s)
- Frans Stellaard
- Institute for Clinical Chemistry and Clinical Pharmacology, University Clinics of Bonn, Germany
| | - Klaus von Bergmann
- Institute for Clinical Chemistry and Clinical Pharmacology, University Clinics of Bonn, Germany
| | - Thomas Sudhop
- Institute for Clinical Chemistry and Clinical Pharmacology, University Clinics of Bonn, Germany
| | - Dieter Lütjohann
- Institute for Clinical Chemistry and Clinical Pharmacology, University Clinics of Bonn, Germany.
| |
Collapse
|
6
|
Mutemberezi V, Guillemot-Legris O, Muccioli GG. Oxysterols: From cholesterol metabolites to key mediators. Prog Lipid Res 2016; 64:152-169. [PMID: 27687912 DOI: 10.1016/j.plipres.2016.09.002] [Citation(s) in RCA: 230] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 09/13/2016] [Accepted: 09/23/2016] [Indexed: 12/13/2022]
Abstract
Oxysterols are cholesterol metabolites that can be produced through enzymatic or radical processes. They constitute a large family of lipids (i.e. the oxysterome) involved in a plethora of physiological processes. They can act through GPCR (e.g. EBI2, SMO, CXCR2), nuclear receptors (LXR, ROR, ERα) and through transporters or regulatory proteins. Their physiological effects encompass cholesterol, lipid and glucose homeostasis. Additionally, they were shown to be involved in other processes such as immune regulatory functions and brain homeostasis. First studied as precursors of bile acids, they quickly emerged as interesting lipid mediators. Their levels are greatly altered in several pathologies and some oxysterols (e.g. 4β-hydroxycholesterol or 7α-hydroxycholestenone) are used as biomarkers of specific pathologies. In this review, we discuss the complex metabolism and molecular targets (including binding properties) of these bioactive lipids in human and mice. We also discuss the genetic mouse models currently available to interrogate their effects in pathophysiological settings. We also summarize the levels of oxysterols reported in two key organs in oxysterol metabolism (liver and brain), plasma and cerebrospinal fluid. Finally, we consider future opportunities and directions in the oxysterol field in order to gain a better insight and understanding of the complex oxysterol system.
Collapse
Affiliation(s)
- Valentin Mutemberezi
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Université catholique de Louvain, Belgium
| | - Owein Guillemot-Legris
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Université catholique de Louvain, Belgium
| | - Giulio G Muccioli
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Université catholique de Louvain, Belgium.
| |
Collapse
|
7
|
Racine R, Grandcolas L, Grison S, Stefani J, Delissen O, Gourmelon P, Veyssière G, Souidi M. Cholesterol 7alpha-hydroxylase (CYP7A1) activity is modified after chronic ingestion of depleted uranium in the rat. J Steroid Biochem Mol Biol 2010; 120:60-6. [PMID: 20362056 DOI: 10.1016/j.jsbmb.2010.03.066] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 03/22/2010] [Accepted: 03/23/2010] [Indexed: 12/01/2022]
Abstract
Depleted uranium (DU) is a radioactive heavy metal derived from the nuclear energy production. Its wide use in civilian and military items increases the risk of its environmental dissemination, and thus the risk of internal contamination of populations living in such contaminated territories. Previous studies have shown that vitamin D and cerebral cholesterol metabolisms were affected following chronic ingestion of DU. Even more than the brain, the liver is a crucial organ in cholesterol homeostasis since it regulates cholesterol distribution and elimination at body level. The aim of this work was to assess the impact of a low-level chronic ingestion of DU on hepatic cholesterol metabolism. Rats were contaminated with DU in their drinking water at a concentration of 40mg/l for 9 months. The major effect induced by DU was a decrease of CYP7A1 specific activity (-60%) correlated with a matching decrease of its product 7alpha-hydroxycholesterol in the plasma. Hepatic gene expression of transporters ABC A1, ABC G5, ABC G8 and of nuclear receptor RXR was increased, whereas that of catabolism enzyme CYP7B1 was decreased. Thus, after a chronic ingestion of DU, rats experience a modulation of cholesterol catabolism but overcome it, since their cholesterolemia is preserved and no pathology is declared.
Collapse
Affiliation(s)
- R Racine
- Institute for Radiological Protection and Nuclear Safety (IRSN), Laboratory of Experimental Toxicology (LRTOX), BP 17, F-92262 Fontenay-aux-Roses Cedex, France
| | | | | | | | | | | | | | | |
Collapse
|
8
|
Pincinato EDC, Moriel P, Abdalla DSP. Cholesterol oxides inhibit cholesterol esterification by lecithin: cholesterol acyl transferase. BRAZ J PHARM SCI 2009. [DOI: 10.1590/s1984-82502009000300007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cholesterol oxides are atherogenic and can affect the activity of diverse important enzymes for the lipidic metabolism. The effect of 7β-hydroxycholesterol, 7-ketocholesterol, 25-hydroxycholesterol, cholestan-3β,5α,6β-triol,5,6β-epoxycholesterol, 5,6α-epoxycholesterol and 7α-hydroxycholesterol on esterification of cholesterol by lecithin:cholesterol acyl transferase (LCAT, EC 2.3.1.43) and the transfer of esters of cholesterol oxides from high density lipoprotein (HDL) to low density lipoproteins (LDL) and very low density lipoproteins (VLDL) by cholesteryl ester transfer protein (CETP) was investigated. HDL enriched with increasing concentrations of cholesterol oxides was incubated with fresh plasma as source of LCAT. Cholesterol and cholesterol oxides esterification was followed by measuring the consumption of respective free sterol and oxysterols. Measurements of cholesterol and cholesterol oxides were done by gas-chromatography. 14C-cholesterol oxides were incorporated into HDL2 and HDL3 subfractions and then incubated with fresh plasma containing LCAT and CETP. The transfer of cholesterol oxide esters was followed by measuring the 14C-cholesterol oxide-derived esters transferred to LDL and VLDL. All the cholesterol oxides studied were esterified by LCAT after incorporation into HDL particles, competing with cholesterol by LCAT. Cholesterol esterification by LCAT was inversely related to the cholesterol oxide concentration. The esterification of 14C-cholesterol oxides was higher in HDL3 and the transfer of the derived esters was greater from HDL2 to LDL and VLDL. The results suggest that cholesterol esterification by LCAT is inhibited in cholesterol oxide-enriched HDL particles. Moreover, the cholesterol oxides-derived esters are efficiently transferred to LDL and VLDL. Therefore, we suggest that cholesterol oxides may exert part of their atherogenic effect by inhibiting cholesterol esterification on the HDL surface and thereby disturbing reverse cholesterol transport.
Collapse
|
9
|
Bertho JM, Roy L, Souidi M, Benderitter M, Bey E, Racine R, Fagot T, Gourmelon P. Initial evaluation and follow-up of acute radiation syndrome in two patients from the Dakar accident. Biomarkers 2009; 14:94-102. [DOI: 10.1080/13547500902773904] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
10
|
Honda A, Yamashita K, Hara T, Ikegami T, Miyazaki T, Shirai M, Xu G, Numazawa M, Matsuzaki Y. Highly sensitive quantification of key regulatory oxysterols in biological samples by LC-ESI-MS/MS. J Lipid Res 2009; 50:350-7. [DOI: 10.1194/jlr.d800040-jlr200] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
11
|
Pikuleva IA. Cholesterol-metabolizing cytochromes P450: implications for cholesterol lowering. Expert Opin Drug Metab Toxicol 2008; 4:1403-14. [PMID: 18950282 PMCID: PMC2957831 DOI: 10.1517/17425255.4.11.1403] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Cardiovascular disease (CVD) continues to be a leading cause of death worldwide. Elevated serum cholesterol is one of the classical risk factors for CVD, which also include age, hypertension, smoking, diabetes mellitus, obesity and family history. Several therapeutic drug classes have been developed to treat hypercholesterolemia; yet, an important percentage of patients do not reach their treatment goals. Therefore, new cholesterol-lowering medications that have sites of action different from that of drugs available at present need to be developed. This review summarizes new information about cytochrome P450 enzymes 7A1, 27A1 and 46A1. These enzymes play key roles in cholesterol elimination and have the potential to serve as targets for cholesterol-lowering.
Collapse
Affiliation(s)
- Irina A Pikuleva
- Case Western Reserve University, University Hospitals Case Medical Center, Department of Ophthalmology and Visual Sciences, Cleveland, OH 44106, USA.
| |
Collapse
|
12
|
Bertho JM, Roy L, Souidi M, Benderitter M, Gueguen Y, Lataillade JJ, Prat M, Fagot T, De Revel T, Gourmelon P. New Biological Indicators to Evaluate and Monitor Radiation-Induced Damage: An Accident Case Report. Radiat Res 2008; 169:543-50. [DOI: 10.1667/rr1259.1] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Accepted: 12/19/2007] [Indexed: 11/03/2022]
|
13
|
Yoshida T, Honda A, Miyazaki H, Matsuzaki Y. Determination of key intermediates in cholesterol and bile acid biosynthesis by stable isotope dilution mass spectrometry. ANALYTICAL CHEMISTRY INSIGHTS 2008; 3:45-60. [PMID: 19609389 PMCID: PMC2701176 DOI: 10.4137/aci.s611] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
For more than a decade, we have developed stable isotope dilution mass spectrometry methods to quantify key intermediates in cholesterol and bile acid biosynthesis, mevalonate and oxysterols, respectively. The methods are more sensitive and reproducible than conventional radioisotope (RI), gas-chromatography (GC) or high-performance liquid chromatography (HPLC) methods, so that they are applicable not only to samples from experimental animals but also to small amounts of human specimens. In this paper, we review the development of stable isotope dilution mass spectrometry for quantifying mevalonate and oxysterols in biological materials, and demonstrate the usefulness of this technique.
Collapse
|
14
|
Abstract
By participating in pathways of cholesterol biosynthesis and elimination, different cytochrome P450 (P450 or CYP) enzymes play an important role in maintenance of cholesterol homeostasis. CYP51 is involved in cholesterol biosynthesis, whereas CYP 7A1, 27A1, 46A1, 7B1, 39A1, and 8B1 are the key enzymes in cholesterol catabolism to bile acids, the major route of cholesterol elimination in mammals. Cholesterol transformations to steroid hormones are also initiated by the P450 enzyme CYP11A1. Finally, one of the major drug-metabolizing P450s CYP3A4 seems to contribute to bile acid biosynthesis as well. The 9 P450s will be the focus of this review and assessed as drug targets for cholesterol lowering.
Collapse
Affiliation(s)
- Irina A Pikuleva
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1031, USA.
| |
Collapse
|
15
|
Abstract
By catalyzing the first steps in different pathways of cholesterol degradation, cytochromes P450 (P450s) 7A1, 27A1, 11A1, and 46A1 play key roles in cholesterol homeostasis. CYP7A1 is a microsomal liver-specific enzyme that converts cholesterol to 7alpha-hydroxycholesterol. CYP27A1 is a ubiquitously expressed mitochondrial P450 that metabolizes cholesterol to 27-hydroxycholesterol. CYP11A1 also resides in mitochondria but is expressed mainly in steroidogenic tissues, where it catalyzes the conversion of cholesterol to pregnenolone. Finally, CYP46A1 is a brain-selective microsomal monooxygenase producing 24S-hydroxycholesterol from cholesterol. Catalytic efficiencies of cholesterol-metabolizing P450s vary significantly and probably reflect physiological requirements of different organs for the rate of cholesterol turnover. P450s 7A1, 27A1, 11A1, and 46A1 represent a unique system for elucidation of how different enzymes have adapted to fit their specific roles in cholesterol elimination. Studies of cholesterol-metabolizing P450s suggest that their activities could be modulated post-translationally and that they should also be considered as targets for regulation of cholesterol homeostasis.
Collapse
Affiliation(s)
- Irina A Pikuleva
- Department of Pharmacology and Toxicology, University of Texas, Medical Branch, 301 University Blvd., Galveston, TX 77555-1031, USA.
| |
Collapse
|
16
|
Del Puppo M, Crosignani A, Longo M, Zuin M, Podda M, Galli G, De Fabiani E, Ciuffreda P, Santaniello E, Javitt NB, Kienle MG. A minimally invasive technique for the evaluation of the regulatory steps of the two major pathways of bile acid synthesis. Clin Chim Acta 2005; 355:23-31. [PMID: 15820474 DOI: 10.1016/j.cccn.2004.11.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2004] [Revised: 11/29/2004] [Accepted: 11/29/2004] [Indexed: 11/29/2022]
Abstract
BACKGROUND Bile acid synthesis accounts for more than 95% of total cholesterol catabolism per day. We have developed a minimally invasive technique in humans that quantifies the rates of plasma appearance of 7alpha- and 27-hydroxycholesterol, representing the first steps of the "classical" and "alternative" pathways of bile acid synthesis, respectively. METHODS For this purpose, during the intravenous infusion of synthetic deuterated isotopomers of 7alpha-hydroxycholesterol and 27-hydroxycholesterol plasma samples are collected and analysed by a GC-MS based method that allows to quantify the exogenous/natural isotopomer ratio of the two sterols. From this data, the rates of plasma appearance of 7alpha- and 27-hydroxycholesterol are calculated. RESULTS In a group of healthy individuals steady state kinetics are obtained during a 2 h period yielding mean values of 2.0+/-0.8 and 3.7+/-0.6 mg/h for 7alpha- and 27-hydroxycholesterol, respectively. The data are consistent with findings using older techniques that require studies over several days. CONCLUSION Considering that at steady state of the exogenous/natural isotopomer ratio the plasma appearance of the two regulatory hydroxysterols are related to the rate of bile acid synthesis via the "classical" and the "alternative" pathways, respectively, the proposed method could be used to evaluate the immediate effects of different diets and drugs and other determinants on cholesterol catabolism.
Collapse
Affiliation(s)
- Marina Del Puppo
- Dipartimento di Medicina Sperimentale, Ambientale e Biotecnologie Mediche (DIMESAB), University of Milano-Bicocca, Via Cadore 48, 20052 Monza, Italy.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Prunet C, Petit JM, Ecarnot-Laubriet A, Athias A, Miguet-Alfonsi C, Rohmer JF, Steinmetz E, Néel D, Gambert P, Lizard G. High circulating levels of 7beta- and 7alpha-hydroxycholesterol and presence of apoptotic and oxidative markers in arterial lesions of normocholesterolemic atherosclerotic patients undergoing endarterectomy. ACTA ACUST UNITED AC 2005; 54:22-32. [PMID: 16376175 DOI: 10.1016/j.patbio.2004.11.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2004] [Accepted: 11/22/2004] [Indexed: 11/19/2022]
Abstract
In previous investigations, we found that 7beta-hydroxycholesterol had potent pro-apoptotic, and pro-oxidative properties. So, we asked whether the circulating level of this oxysterol was enhanced in atherosclerotic patients undergoing endarterectomy of the superficial femoral artery. To this end, 7beta-hydroxycholesterol serum concentrations were determined and compared with common lipid parameters in atherosclerotic patients, and in healthy subjects. 7alpha-hydroxycholesterol was simultaneously measured to evaluate the reliability of the method used for oxysterol analysis. On normal and atherosclerotic arterial fragments from patients, markers of oxidation (4-hydroxynonenal (4-HNE) adducts), and apoptosis (activated caspase-3; condensed/fragmented nuclei) were studied. Interestingly, high serum concentrations of 7beta- and 7alpha-hydroxycholesterol were found in normocholesterolemic atherosclerotic patients. However, in statin-treated patients, the circulating levels of 7beta- and 7alpha-hydroxycholesterol tend towards normal values. Therefore, 7beta- as well as 7alpha-hydroxycholesterol could be more appropriate markers of lipid metabolism disorders than cholesterol or LDL in normocholesterolemic patients with atherosclerosis of the lower limbs, and statins could normalize their serum concentrations. At the arterial level, apoptotic cells were mainly identified in low grade lesions and no statin effects were found on oxidation and apoptosis.
Collapse
Affiliation(s)
- C Prunet
- Laboratoire de Biochimie Médicale, INSERM U498/IFR 100, CHU/Hôpital du Bocage, BP 77908, 21079 Dijon cedex, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Honda A, Yoshida T, Xu G, Matsuzaki Y, Fukushima S, Tanaka N, Doy M, Shefer S, Salen G. Significance of plasma 7alpha-hydroxy-4-cholesten-3-one and 27-hydroxycholesterol concentrations as markers for hepatic bile acid synthesis in cholesterol-fed rabbits. Metabolism 2004; 53:42-8. [PMID: 14681840 DOI: 10.1016/j.metabol.2003.07.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Plasma 7alpha-hydroxy-4-cholesten-3-one has been used as an index of hepatic bile acid synthesis. The aim of the current study was to ascertain whether the level of this oxysterol reflects hepatic cholesterol 7alpha-hydroxylase activity when plasma cholesterol concentrations are markedly changed. In addition, the relationship of hepatic sterol 27-hydroxylase activity with plasma concentrations of 27-hydroxycholesterol and 3beta-hydroxy-5-cholestenoic acid was studied. We used New Zealand white rabbits fed 2% cholesterol for 5 or 10 days and/or constructed bile fistula. Feeding cholesterol markedly increased and bile drainage reduced plasma cholesterol concentrations. Initially, in these models there was no correlation between plasma 7alpha-hydroxy-4-cholesten-3-one concentrations and hepatic cholesterol 7alpha-hydroxylase activities (r = -0.24, n = 10). Cholesterol feeding was associated with downregulated 7alpha-hydroxylase activities, while plasma 7alpha-hydroxy-4-cholesten-3-one concentrations were elevated in the presence of increased plasma cholesterol levels. However, this discrepancy was overcome and significant correlation was observed (r = 0.73, P <.05, n = 10) by expressing 7alpha-hydroxy-4-cholesten-3-one levels relative to cholesterol. In contrast, hepatic sterol 27-hydroxylase activities were not significantly correlated with plasma absolute (r = 0.23, difference not significant [NS], n = 10) nor cholesterol-related levels of 27-hydroxycholesterol (r = -0.13, NS, n = 10), or 3beta-hydroxy-5-cholestenoic acid concentrations (r = 0.30, NS, n = 10). In conclusion, plasma 7alpha-hydroxy-4-cholesten-3-one concentrations reflected hepatic cholesterol 7alpha-hydroxylase activities when the sterol levels were adjusted to plasma cholesterol concentrations in rabbits with hypercholesterolemia. The results suggest that plasma 7alpha-hydroxy-4-cholesten-3-one relative to cholesterol is a better marker for hepatic cholesterol 7alpha-hydroxylase activity than the absolute concentration when hypercholesterolemia is present. In contrast, 27-hydroxycholesterol and 3beta-hydroxy-5-cholestenoic acid levels in plasma did not reflect hepatic sterol 27-hydroxylase activities even if the levels were adjusted to plasma cholesterol concentrations.
Collapse
Affiliation(s)
- Akira Honda
- Ibaraki Prefectural Institute of Public Health, Mito, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Abstract
This article describes the most commonly used procedures and recent laboratory methodologies using gas and liquid chromatography developed for separation and quantitation of non-saponifiable steroidal lipids from clinical (human) studies, edible fats and oils or fatty foods.
Collapse
Affiliation(s)
- P Volin
- Caloniuksenk. 10 C 47, Helsinki, Finland
| |
Collapse
|
20
|
Del Puppo M, Kienle MG, Crosignani A, Petroni M, Amati B, Zuin M, Podda M. Cholesterol metabolism in primary biliary cirrhosis during simvastatin and UDCA administration. J Lipid Res 2001. [DOI: 10.1016/s0022-2275(20)31668-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
21
|
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.
Collapse
Affiliation(s)
- G J Schroepfer
- Departments of Biochemistry, Rice University, Houston, Texas, USA.
| |
Collapse
|
22
|
Kuroki S, Naito T, Chijiiwa K, Tanaka M. Effects of cholestyramine on hepatic cholesterol 7alpha-hydroxylase and serum 7alpha-hydroxycholesterol in the hamster. Lipids 1999; 34:817-23. [PMID: 10529092 DOI: 10.1007/s11745-999-0428-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Cholestyramine increases activities of hepatic cholesterol 7alpha-hydroxylase and serum levels of 7alpha-hydroxycholesterol. To examine if serum 7alpha-hydroxycholesterol levels parallel with enzyme activity, 0, 0.5, 1, 2, 4, and 10% of cholestyramine was administered to female golden Syrian hamsters for 28 d in the dose-dependent study, and 2% cholestyramine for 0, 1, 3, 7, 14, 21, and 28 d in the time-dependent study. In the dose-dependent study, hepatic and serum cholesterol levels were significantly decreased dose-dependently when more than 0.5% of cholestyramine was fed for 28 d. Cholestyramine increased the cholesterol 7alpha-hydroxylase activity in a dose-dependent manner, while the serum 7alpha-hydroxycholesterol level was essentially unchanged. No correlation was found between the serum level and the hepatic enzyme activity. In the time-dependent study, hepatic and serum cholesterol levels markedly decreased when 2% cholestyramine was fed for longer than 3 d. The serum triglyceride level increased significantly for the first 7 d and then decreased. Cholesterol 7alpha-hydroxylase activity increased significantly as early as day 1, reached maximum activity level on day 7, and then kept the significantly high values until day 28. The serum 7alpha-hydroxycholesterol level significantly increased for the first 7 d and decreased to the pretreatment level thereafter. 7Alpha-hydroxycholesterol levels significantly correlated with serum cholesterol and triglyceride levels. We conclude that the serum 7alpha-hydroxycholesterol level does not always reflect the activity of hepatic cholesterol 7alpha-hydroxylase, when cholesterol metabolism is severely disturbed by cholestyramine.
Collapse
Affiliation(s)
- S Kuroki
- Department of Surgery I, Kyushu University Faculty of Medicine, Fukuoka, Japan.
| | | | | | | |
Collapse
|
23
|
Abstract
Clinical studies have clearly established a relationship between bile acid synthesis and plasma LDL-cholesterol concentrations. Interruption of the enterohepatic circulation of bile acids leads to increased bile acid synthesis and a reduction in plasma LDL-cholesterol concentrations. New studies indicate that genetic variation in cholesterol 7alpha-hydroxylase activity accounts for a significant fraction of the inter-individual variation in plasma LDL-cholesterol concentrations in the general population, and a specific CYP7A1 allele associated with increased plasma LDL-cholesterol concentrations has been identified. Studies in which cholesterol 7alpha-hydroxylase was transiently overexpressed in hamsters and mice indicate that direct manipulation of cholesterol 7alpha-hydroxylase leads to changes in plasma LDL-cholesterol concentrations. Interestingly, targeted inactivation of the gene encoding cholesterol 7alpha-hydroxylase does not lead to increased plasma LDL-cholesterol concentrations in mice.
Collapse
Affiliation(s)
- J C Cohen
- The Centre for Human Nutrition and Department of Internal Medicine, University of Texas Southwestern Medical Centre, Dallas 75235-9052, USA.
| |
Collapse
|
24
|
Saisho Y, Shimada C, Umeda T. Determination of 7alpha-hydroxycholesterol in dog plasma by high-performance liquid chromatography with fluorescence detection. Anal Biochem 1998; 265:361-7. [PMID: 9882415 DOI: 10.1006/abio.1998.2915] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A new method was developed for the determination of 7alpha-hydroxycholesterol (7-HC) in dog plasma by means of high-performance liquid chromatography (HPLC) with fluorescence detection. 7-HC extracted with organic solvent from plasma was purified with Bond Elut 2OH and converted to a sensitive fluorescent derivative containing double coumarin groups at the C-3 and C-7 positions of the steroid nucleus with 7-methoxycoumarin-3-carbonyl azide. After removal of the excess reagent with Bond Elut NH2, the 7-HC derivative was separated by reverse-phase HPLC method. The detection limit of the authentic 7-HC-3,7-coumarin derivative was 4 pg (S/N = 5), approximately four times less than that of the 7-HC-3-anthroyl derivative yielded by reaction of 7-HC with 1-anthroylcyanide. The newly developed method was used to investigate the effects of consecutive oral administrations of cholestyramine (CA) on 7-HC levels in dog plasma. The plasma 7-HC levels of the CA-treated group were two times greater than those of the control group.
Collapse
Affiliation(s)
- Y Saisho
- Shionogi Research Laboratories, Shionogi & Company, Ltd., 12-4 Sagisu 5-Chome, Osaka, Fukushima-ku, 553-0002, Japan.
| | | | | |
Collapse
|
25
|
Tint GS, Pentchev P, Xu G, Batta AK, Shefer S, Salen G, Honda A. Cholesterol and oxygenated cholesterol concentrations are markedly elevated in peripheral tissue but not in brain from mice with the Niemann-Pick type C phenotype. J Inherit Metab Dis 1998; 21:853-63. [PMID: 9870211 DOI: 10.1023/a:1005474803278] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Niemann-Pick disease type C (NP-C) is a rare genetic disorder characterized by progressive neurodegeneration, frequent developmental delay and early death. Tissues of affected individuals accumulate large quantities of free cholesterol in lysosomes. Because cytotoxic oxygenated derivatives of cholesterol are known to form readily when cholesterol concentrations are elevated, we searched for these compounds in liver, kidney, spleen and brain from mice with the NP-C phenotype. In order of abundance, we identified 7 alpha- and 7 beta-hydroxycholesterol, 5 alpha, 6 alpha-epoxycholestan-3 beta-ol, 4 beta-hydroxycholesterol, cholest-4-en-3 beta, 7 alpha-diol and cholest-4-en-3 beta, 6 beta-diol in most tissue samples. Cholesterol concentrations in affected mice were increased 3-fold in kidney and 7- to 8-fold in spleen and liver compared to controls (all p < 0.001) but were unchanged in brain. Although oxysterol levels were markedly elevated in nonbrain tissue, the oxysterol and cholesterol concentrations increased proportionally so that oxysterols expressed as percentage of total sterols were the same for all animals (0.34 +/- 0.19% averaged over all organs in affected animals vs 0.40 +/- 0.42% in control mice). In contrast to peripheral tissue, we could not detect any increase in either absolute or relative oxysterol levels in the brains of affected and control mice (49 +/- 61 vs 53 +/- 43 micrograms/g wet weight and 0.45 +/- 0.52 vs 0.47 +/- 0.37%, respectively). Thus, brain sterols are normal in NP-C mice and it is unlikely that an accumulation of cytotoxic oxygenated derivatives of cholesterol could account for the progressive neuropathology seen in the disease.
Collapse
Affiliation(s)
- G S Tint
- Department of Veterans Affairs New Jersey Health Care System, East Orange, New Jersey 07018, USA
| | | | | | | | | | | | | |
Collapse
|
26
|
Serum 27-hydroxycholesterol in patients with primary biliary cirrhosis suggests alteration of cholesterol catabolism to bile acids via the acidic pathway. J Lipid Res 1998. [DOI: 10.1016/s0022-2275(20)33328-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
27
|
Hainer JW, Hunninghake DB, Benedek IH, Broyles FE, Garner DM, Jenkins RM, McGinn A, Pieniaszek HJ, London E, Gillies PJ. DMP 504, a novel hydrogel bile acid sequestrant: III. Safety, tolerability, and cholesterol-lowering in healthy hypercholesterolemic subjects. Drug Dev Res 1997. [DOI: 10.1002/(sici)1098-2299(199706)41:2<76::aid-ddr4>3.0.co;2-o] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
28
|
Hahn C, von Bergmann K. Relationship between the serum concentration of 7 alpha-hydroxycholesterol and fecal bile acid excretion in humans. Scand J Gastroenterol 1996; 31:804-8. [PMID: 8858751 DOI: 10.3109/00365529609010356] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Serum levels of 7 alpha-hydroxycholesterol have been shown to reflect the activity of cholesterol 7 alpha-hydroxylase, the key enzyme of bite acid synthesis in the liver, but a comparison with direct measurements of bile acid synthesis rates has never been performed. METHODS 7 alpha-Hydroxycholesterol was measured by gas-liquid chromatography/mass spectrometry and bile acid synthesis by the fecal balance method in 35 subjects. RESULTS A significant correlation was found between 7 alpha-hydroxycholesterol concentration in serum and bile acid synthesis (r = 0.863, p < 0.001). Serum levels of 7 alpha-hydroxycholesterol in 20 patients treated with a 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor did not differ from levels obtained in healthy volunteers (78 +/- 7 ng/ml versus 63 +/- 5 ng/ml; NS). Treatment with fenofibrate reduced 7 alpha-hydroxycholesterol concentrations in six patients from 107 +/- 47 ng/ml to 61 +/- 12 ng/ml (p < 0.05). CONCLUSIONS We conclude that the concentration of 7 alpha-hydroxycholesterol in serum is an indicator of bile acid synthesis and that serum levels of 7 alpha-hydroxycholesterol are not affected in patients treated with HMG-CoA reductase inhibitors but are affected in those treated with fenofibrate.
Collapse
Affiliation(s)
- C Hahn
- Dept. of Clinical Pharmacology, University of Bonn, Germany
| | | |
Collapse
|
29
|
Abstract
Material dealing with the chemistry, biochemistry, and biological activities of oxysterols is reviewed for the period 1987-1995. Particular attention is paid to the presence of oxysterols in tissues and foods and to their physiological relevance.
Collapse
Affiliation(s)
- L L Smith
- University of Texas Medical Branch, Galveston 77555-0653, USA
| |
Collapse
|
30
|
Honda A, Yoshida T, Tanaka N, Matsuzaki Y, He B, Shoda J, Osuga T. Accumulation of 7 alpha-hydroxycholesterol in liver tissue of patients with cholesterol gallstones. J Gastroenterol 1995; 30:651-6. [PMID: 8574339 DOI: 10.1007/bf02367793] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Patients with cholesterol gallstones have a reduced pool of bile acids. This study was undertaken to clarify the mechanism by which bile acid biosynthesis does not increase to supranormal levels to cause a reexpansion of the pool. We investigated the first two steps of the bile acid biosynthesis pathway by assaying the activities of cholesterol 7 alpha-hydroxylase, the rate-limiting enzyme in this pathway, and 3 beta-hydroxy-delta 5-C27-steroid dehydrogenase/isomerase, and by measuring the concentrations of 7 alpha-hydroxycholesterol and 7 alpha-hydroxy-4-cholesten-3-one in liver specimens from ten patients with cholesterol gallstones and ten gallstone-free controls. In the patients with gallstones, cholesterol 7 alpha-hydroxylase activity, 3 beta-hydroxy-delta 5-C27-steroid dehydrogenase/isomerase activity, and hepatic 7 alpha-hydroxy-4-cholesten-3-one concentration did not significantly different from levels in controls, but hepatic 7 alpha-hydroxycholesterol concentration was more than twofold that of controls (12.9 +/- 2.6 vs 5.3 +/- 1.2 nmol/g liver, P < 0.01). The concentration of 7 alpha-hydroxycholesterol positively correlated with the ratio of cholesterol 7 alpha-hydroxylase activity to 3 beta-hydroxy-delta 5-C27-steroid dehydrogenase/isomerase activity (r = 0.93; P < 0.005) in the gallstone-free controls. In contrast, this correlation disappeared in the patients with gallstones. These results suggest a derangement of the normal 7 alpha-hydroxycholesterol metabolism in the patients with gallstones. The reason for the accumulation of 7 alpha-hydroxycholesterol remains unclear; however, it is possible that, in patients with cholesterol gallstone, the accumulated 7 alpha-hydroxycholesterol causes inappropriate suppression of cholesterol 7 alpha-hydroxylase activity by product inhibition.
Collapse
Affiliation(s)
- A Honda
- Department of Gastroenterology, University of Tsukuba, Japan
| | | | | | | | | | | | | |
Collapse
|
31
|
Hahn C, Reichel C, von Bergmann K. Serum concentration of 7 alpha-hydroxycholesterol as an indicator of bile acid synthesis in humans. J Lipid Res 1995. [DOI: 10.1016/s0022-2275(20)41123-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
32
|
Szedlacsek SE, Wasowicz E, Hulea SA, Nishida HI, Kummerow FA, Nishida T. Esterification of oxysterols by human plasma lecithin-cholesterol acyltransferase. J Biol Chem 1995; 270:11812-9. [PMID: 7744831 DOI: 10.1074/jbc.270.20.11812] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
In the present study, lecithin-cholesterol acyltransferase (LCAT) catalyzed esterification of oxysterols was investigated by using discoidal bilayer particles (DBP) containing various oxysterols, phosphatidylcholines, and apolipoprotein A-I. The esterified oxysterols were analyzed by high pressure liquid chromatography, gas chromatography, and mass spectrometry. LCAT esterified all oxysterols tested that are known to be present in human plasma. The esterification yields in almost all cases were relatively high, often as high as the yield of cholesterol esterification. When DBP preparations containing 27-hydroxycholesterol and various phosphatidylcholines were used for the LCAT reaction, both monoesters and diesters were produced. The mass spectrometry analysis showed that the monoester was produced by the esterification of the 3 beta-hydroxyl group and not the 27-hydroxyl group. The diesters were apparently produced by the esterification of the 27-hydroxyl group only after the esterification of the 3 beta-hydroxyl group. Phosphatidylcholine containing a saturated acyl group at sn-1 position and an unsaturated acyl group at sn-2 position gave generally high esterification yield. The esterification of various oxysterols was compared by using DBP containing dioleoyl-phosphatidylcholine and individual oxysterols. All oxysterols produced 3 beta-oleoyl monoesters. Unlike 27-hydroxycholesterol, 25-hydroxycholesterol, 7 alpha-hydroxycholesterol, 7 beta-hydroxycholesterol, or cholestanetriol did not produce diesters. Various factors influencing the formation of the monoesters and diesters from 27-hydroxycholesterol were investigated. When dioleoyl-phosphatidylcholine was used as the acyl donor, prolonged dialysis of DBP preparations and increase in the ratio of the enzyme concentration to substrate particle concentration increased the diester formation. Significant amounts of diesters were also produced by using 1-palmitoyl-2-oleoyl-phosphatidylcholine and other phosphatidylcholines as the acyl donors. By analyzing the conditions of monoester and diester formation, a scheme for the LCAT reaction pathway was proposed.
Collapse
Affiliation(s)
- S E Szedlacsek
- Burnsides Research Laboratory, Department of Food Science, University of Illinois, Urbana 61801, USA
| | | | | | | | | | | |
Collapse
|
33
|
Fukushima K, Ichimiya H, Higashijima H, Yamashita H, Kuroki S, Chijiiwa K, Tanaka M. Regulation of bile acid synthesis in the rat: relationship between hepatic cholesterol 7 alpha-hydroxylase activity and portal bile acids. J Lipid Res 1995. [DOI: 10.1016/s0022-2275(20)39908-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
|
34
|
Yoshida T, Honda A, Tanaka N, Matsuzaki Y, Shoda J, He B, Osuga T, Miyazaki H. Determination of 7 alpha-hydroxy-4-cholesten-3-one level in plasma using isotope-dilution mass spectrometry and monitoring its circadian rhythm in human as an index of bile acid biosynthesis. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL APPLICATIONS 1994; 655:179-87. [PMID: 8081463 DOI: 10.1016/0378-4347(94)00107-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A highly sensitive and specific method has been developed for determination of the level of 7 alpha-hydroxy-4-cholesten-3-one in plasma. This method is based on a stable isotope-dilution technique by gas chromatography-selected-ion monitoring mass spectrometry. 7 alpha-Hydroxy-4-cholesten-3-one was extracted from plasma by saltingout extraction, and then purified by serial solid-phase extractions. The extract was treated with O-methylhydroxyl-amine hydrochloride and then dimethylethylsilylated. The resulting methyloxime-dimethylethylsilyl ether derivative was quantified by gas chromatography-selected-ion monitoring mass spectrometry with a high-resolution mode. The plasma levels of 7 alpha-hydroxy-4-cholesten-3-one were correlated with the cholesterol 7 alpha-hydroxylase activity to a higher degree than those of any other form of 7 alpha-hydroxycholesterol (r = 0.84, n = 16, p < 0.0001). The present method was applied to monitor the circadian rhythm of 7 alpha-hydroxy-4-cholesten-3-one levels in human plasma. It was concluded that the plasma level of 7 alpha-hydroxy-4-cholesten-3-one is a useful index for the monitoring of bile acid biosynthesis in the human liver.
Collapse
Affiliation(s)
- T Yoshida
- Department of Gastroenterology, University of Tsukuba, Ibaraki, Japan
| | | | | | | | | | | | | | | |
Collapse
|
35
|
Nakashima N, Sakai Y, Sakai H, Yanase T, Haji M, Umeda F, Koga S, Hoshita T, Nawata H. A point mutation in the bile acid biosynthetic enzyme sterol 27-hydroxylase in a family with cerebrotendinous xanthomatosis. J Lipid Res 1994. [DOI: 10.1016/s0022-2275(20)41180-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|
36
|
Okamoto S, Nakano K, Kosahara K, Kishinaka M, Oda H, Ichimiya H, Chijiiwa K, Kuroki S. Effects of pravastatin and ursodeoxycholic acid on cholesterol and bile acid metabolism in patients with cholesterol gallstones. J Gastroenterol 1994; 29:47-55. [PMID: 8199696 DOI: 10.1007/bf01229073] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To investigate the effects of pravastatin and ursodeoxycholic acid (UDCA) on cholesterol and bile acid metabolism in humans, 41 patients with cholesterol gallstone disease were allocated to four groups and treated with pravastatin (20 mg/day), UDCA (600 mg/day), both pravastatin and UDCA, or neither drug (control) for 1-2 weeks prior to elective cholecystectomy. Cholesterol 7 alpha-hydroxylase activity and serum levels of total 7 alpha-hydroxycholesterol were significantly increased by pravastatin and unaffected by UDCA. 3-Hydroxy-3-methylglutaryl coenzyme A reductase activity was markedly increased by pravastatin and decreased by UDCA. UDCA significantly decreased biliary cholesterol concentration and the cholesterol saturation index and prolonged the nucleation time; however, pravastatin alone had little effect on biliary lithogenicity. Serum total and low-density lipoprotein (LDL)-cholesterol levels were reduced most by the combined administration of pravastatin and UDCA. In conclusion, at a dose of 20 mg/day, pravastatin increased bile acid synthesis but did not decrease biliary lithogenicity. UDCA had no significant effect on bile acid synthesis, but markedly decreased biliary lithogenicity.
Collapse
Affiliation(s)
- S Okamoto
- First Department of Surgery, Kyushu University Faculty of Medicine, Fukuoka, Japan
| | | | | | | | | | | | | | | |
Collapse
|
37
|
Einarsson K. Effect of ursodeoxycholic acid on hepatic cholesterol metabolism. SCANDINAVIAN JOURNAL OF GASTROENTEROLOGY. SUPPLEMENT 1994; 204:19-23. [PMID: 7824873 DOI: 10.3109/00365529409103620] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Oral administration of ursodeoxycholic acid (UDCA) renders bile unsaturated with cholesterol by reducing the hepatic output of cholesterol. Theoretically, several mechanisms may be of importance. In the present overview, the effect of treatment with UDCA on hepatic cholesterol metabolism is evaluated, in particular the influence on hepatic cholesterol synthesis, 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase activity, bile acid synthesis, 7 alpha-hydroxylation of cholesterol, and esterification of cholesterol--acyl coenzyme A: cholesterol acetyltransferase (ACAT) activity. It is apparent that UDCA treatment does not inhibit the hepatic HMG CoA reductase activity. Neither is ACAT activity or the cholesteryl ester content changed by UDCA. The catabolism of cholesterol to bile acids is unaffected or slightly increased during administration of UDCA. It is concluded that a stimulated degradation of cholesterol to bile acids may partly explain the decrease in hepatic secretion of cholesterol obtained during UDCA administration. It is suggested that the reduction in cholesterol absorption from the intestine seen during UDCA therapy may also be of importance.
Collapse
Affiliation(s)
- K Einarsson
- Dept. of Gastroenterology and Hepatology, Karolinska Institute, Huddinge University Hospital, Sweden
| |
Collapse
|
38
|
Honda A, Yoshida T, Tanaka N, Matsuzaki Y, He B, Osuga T, Kobayashi N, Ozawa K. Hepatic cholesterol and bile acid synthesis in Japanese patients with cholesterol gallstones. GASTROENTEROLOGIA JAPONICA 1993; 28:406-14. [PMID: 8344502 DOI: 10.1007/bf02776986] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In Japan the composition of gallstones is changing rapidly from the once-predominant brown-pigment stones to cholesterol ones. The present work was undertaken to clarify the mechanism of cholesterol supersaturated bile production in Japanese patients with cholesterol gallstones. In 26 non-obese and normolipidemic patients (11 with cholesterol gallstones, 8 with black- or brown-pigment gallstones, 7 without gallstones) a liver biopsy and hepatic bile were surgically obtained under standardized conditions. The cholesterol saturation of hepatic bile was significantly higher in cholesterol gallstone patients than in gallstone-free controls (195 +/- 10 vs. 146 +/- 8%, respectively; P < 0.01). The microsomal activities of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, the rate-limiting enzyme for cholesterol synthesis, cholesterol 7 alpha-hydroxylase, the rate-limiting enzyme for bile acid synthesis, and 7 alpha-hydroxy-4-cholesten-3-one 12 alpha-hydroxylase (12 alpha-hydroxylase), the rate-limiting enzyme for cholic acid synthesis, were assayed simultaneously in the same subjects. There were positive correlations between HMG-CoA reductase and cholesterol 7 alpha-hydroxylase activities (Rs = 0.62, P < 0.005), and between cholesterol 7 alpha-hydroxylase and 12 alpha-hydroxylase activities (Rs = 0.44, P < 0.05) in all subjects, irrespective of the existence of gallstones. The activities of the three rate-limiting enzymes did not differ significantly among the three groups (cholesterol stone, pigment stone and stone-free). In conclusion, the cholesterol supersaturation of hepatic bile in nonobese and normolipidemic Japanese patients with cholesterol gallstones does not result from an increased hepatic cholesterol synthesis or a decreased bile acid synthesis.
Collapse
Affiliation(s)
- A Honda
- Department of Gastroenterology, University of Tsukuba, Ibaraki, Japan
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Yoshida T, Honda A, Tanaka N, Matsuzaki Y, He B, Osuga T, Kobayashi N, Ozawa K, Miyazaki H. Simultaneous determination of mevalonate and 7 alpha-hydroxycholesterol in human plasma by gas chromatography-mass spectrometry as indices of cholesterol and bile acid biosynthesis. JOURNAL OF CHROMATOGRAPHY 1993; 613:185-93. [PMID: 8491805 DOI: 10.1016/0378-4347(93)80133-o] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A very sensitive and specific method for the simultaneous determination of mevalonate and 7 alpha-hydroxycholesterol in human plasma is described. The assay is based on isotope dilution mass spectrometry: the extracts from plasma were treated with benzylamine followed by dimethylethylsilylimidazole, then the resulting dimethylethylsilyl ether derivatives of mevalonylbenzylamide and 7 alpha-hydroxycholesterol were determined by gas chromatography-mass spectrometry using high-resolution selected-ion monitoring. Simple regression analysis revealed significant correlations between the plasma level of mevalonate and the hepatic activity of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (EC 1.1.1.34) (r = 0.83, P < 0.01) and between the plasma level of free 7 alpha-hydroxycholesterol and the hepatic activity of cholesterol 7 alpha-hydroxylase (EC 1.14.13.7) (r = 0.76, P < 0.05).
Collapse
Affiliation(s)
- T Yoshida
- Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Masanori K, Keigo K, Shuichiro O, Hitoshi O, Hitoshi I, Kazuo C, Syoji K. Metabolism of intravenously administered 7α-hydroxycholesterol-3β-stearate in the hamster. ACTA ACUST UNITED AC 1992. [DOI: 10.1016/0005-2760(92)90190-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|