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Ribeiro RM, Vasconcelos SC, Lima PLGDSB, Coelho EF, Oliveira AMN, Gomes EDABM, Mota LDA, Radtke LS, Carvalho MDS, Araújo DABS, Pinheiro MSN, Gama VCDV, Júnior RMM, Braga Neto P, Nóbrega PR. Pathophysiology and Treatment of Lipid Abnormalities in Cerebrotendinous Xanthomatosis: An Integrative Review. Brain Sci 2023; 13:979. [PMID: 37508912 PMCID: PMC10377253 DOI: 10.3390/brainsci13070979] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 06/19/2023] [Accepted: 06/19/2023] [Indexed: 07/30/2023] Open
Abstract
Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive disorder caused by pathogenic variants in CYP27A1, leading to a deficiency in sterol 27-hydroxylase. This defect results in the accumulation of cholestanol and bile alcohols in various tissues, including the brain, tendons and peripheral nerves. We conducted this review to evaluate lipid profile abnormalities in patients with CTX. A search was conducted in PubMed, Embase and the Virtual Health Library in January 2023 to evaluate studies reporting the lipid profiles of CTX patients, including the levels of cholestanol, cholesterol and other lipids. Elevated levels of cholestanol were consistently observed. Most patients presented normal or low serum cholesterol levels. A decrease in chenodeoxycholic acid (CDCA) leads to increased synthesis of cholesterol metabolites, such as bile alcohols 23S-pentol and 25-tetrol 3-glucuronide, which may serve as surrogate follow-up markers in patients with CTX. Lipid abnormalities in CTX have clinical implications. Cholestanol deposition in tissues contributes to clinical manifestations, including neurological symptoms and tendon xanthomas. Dyslipidemia and abnormal cholesterol metabolism may also contribute to the increased risk of atherosclerosis and cardiovascular complications observed in some CTX patients.
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Affiliation(s)
| | | | | | | | | | | | | | - Lucas Soares Radtke
- Faculty of Medicine, Federal University of Ceara, Fortaleza 60430-372, Brazil
| | | | | | | | | | | | - Pedro Braga Neto
- Division of Neurology, Department of Clinical Medicine, Federal University of Ceara, Fortaleza 60430-372, Brazil
| | - Paulo Ribeiro Nóbrega
- Division of Neurology, Department of Clinical Medicine, Federal University of Ceara, Fortaleza 60430-372, Brazil
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Pannu PS, Allahverdian S, Francis GA. Oxysterol generation and liver X receptor-dependent reverse cholesterol transport: not all roads lead to Rome. Mol Cell Endocrinol 2013; 368:99-107. [PMID: 22884520 DOI: 10.1016/j.mce.2012.07.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 06/30/2012] [Accepted: 07/27/2012] [Indexed: 12/31/2022]
Abstract
Cell cholesterol metabolism is a tightly regulated process, dependent in part on activation of nuclear liver X receptors (LXRs) to increase expression of genes mediating removal of excess cholesterol from cells in the reverse cholesterol transport pathway. LXRs are thought to be activated predominantly by oxysterols generated enzymatically from cholesterol in different cell organelles. Defects resulting in slowed release of cholesterol from late endosomes and lysosomes or reduction in sterol-27-hydroxylase activity lead to specific blocks in oxysterol production and impaired LXR-dependent gene activation. This block does not appear to be compensated by oxysterol production in other cell compartments. The purpose of this review is to summarize current knowledge about oxysterol-dependent activation by LXR of genes involved in reverse cholesterol transport, and what these defects of cell cholesterol homeostasis can teach us about the critical pathways of oxysterol generation for expression of LXR-dependent genes.
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Affiliation(s)
- Parveer S Pannu
- Department of Medicine, UBC James Hogg Research Centre, Institute of Heart and Lung Health at St. Paul's Hospital, Vancouver, BC, Canada V6Z 1Y6.
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3
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Björkhem I, Leoni V, Meaney S. Genetic connections between neurological disorders and cholesterol metabolism. J Lipid Res 2010; 51:2489-503. [PMID: 20466796 PMCID: PMC2918434 DOI: 10.1194/jlr.r006338] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Revised: 05/13/2010] [Indexed: 12/25/2022] Open
Abstract
Cholesterol is an essential component of both the peripheral and central nervous systems of mammals. Over the last decade, evidence has accumulated that disturbances in cholesterol metabolism are associated with the development of various neurological conditions. In addition to genetically defined defects in cholesterol synthesis, which will be covered in another review in this Thematic Series, defects in cholesterol metabolism (cerebrotendinous xanthomatosis) and intracellular transport (Niemann Pick Syndrome) lead to neurological disease. A subform of hereditary spastic paresis (type SPG5) and Huntington's disease are neurological diseases with mutations in genes that are of importance for cholesterol metabolism. Neurodegeneration is generally associated with disturbances in cholesterol metabolism, and presence of the E4 isoform of the cholesterol transporter apolipoprotein E as well as hypercholesterolemia are important risk factors for development of Alzheimer's disease. In the present review, we discuss the links between genetic disturbances in cholesterol metabolism and the above neurological disorders.
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Affiliation(s)
- Ingemar Björkhem
- Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden.
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4
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Björkhem I, Hansson M. Cerebrotendinous xanthomatosis: an inborn error in bile acid synthesis with defined mutations but still a challenge. Biochem Biophys Res Commun 2010; 396:46-9. [PMID: 20494109 DOI: 10.1016/j.bbrc.2010.02.140] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 02/20/2010] [Indexed: 10/19/2022]
Abstract
Cerebrotendinous xanthomatosis [CTX] is a rare disease characterized by the accumulation of cholesterol and cholestanol in brain and tendons caused by a mutation in the sterol 27-hydroxylase gene [CYP27A1] involved in bile acid synthesis. Disruption of this gene in mice does not give rise to xanthomas. The gene defect leads to reduced bile acid synthesis with a compensatory increase in the activity of the rate-limiting enzyme in bile acid synthesis, cholesterol 7alpha-hydroxylase. This leads to a marked accumulation of 7alpha-hydroxylated bile acid precursors, in particular 7alpha-hydroxy-4-cholesten-3-one. The latter oxysterol passes the blood-brain barrier and is an efficient precursor to cholestanol. The activity of cholesterol 7alpha-hydroxylase is normalized by treatment with bile acids. Such treatment reduces the xanthomas in CTX patients in parallel with decreased cholestanol levels. The relationship between the accumulation of cholestanol and the development of cholesterol-rich xanthomas has however not been clarified and a suitable animal model is still lacking.
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Affiliation(s)
- Ingemar Björkhem
- Department of Laboratory Medicine, Division of Clinical Chemistry, Karolinska Institutet, Karolinska University Hospital Huddinge, S-14186 Huddinge, Sweden.
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5
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Hojo K, Hakamata H, Takahashi A, Hosokawa YY, Kusu F. Determination of serum cholestanol by semi-micro high-performance liquid chromatography with electrochemical detection. Biomed Chromatogr 2009; 24:600-5. [DOI: 10.1002/bmc.1332] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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6
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Panzenboeck U, Andersson U, Hansson M, Sattler W, Meaney S, Björkhem I. On the mechanism of cerebral accumulation of cholestanol in patients with cerebrotendinous xanthomatosis. J Lipid Res 2007; 48:1167-74. [PMID: 17325385 DOI: 10.1194/jlr.m700027-jlr200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The most serious consequence of sterol 27-hydroxylase deficiency in humans [cerebrotendinous xanthomatosis (CTX)] is the development of cholestanol-containing brain xanthomas. The cholestanol in the brain may be derived from the circulation or from 7alpha-hydroxylated intermediates in bile acid synthesis, present at 50- to 250-fold increased levels in plasma. Here, we demonstrate a transfer of 7alpha-hydroxy-4-cholesten-3-one across cultured porcine brain endothelial cells (a model for the blood-brain barrier) that is approximately 100-fold more efficient than the transfer of cholestanol. Furthermore, there was an efficient conversion of 7alpha-hydroxy-4-cholesten-3-one to cholestanol in cultured neuronal and glial cells as well as in monocyte-derived macrophages of human origin. It is concluded that the continuous intracellular production of cholestanol from a bile acid precursor capable of rapidly passing biomembranes, including the blood-brain barrier, is likely to be of major importance for the accumulation of cholestanol in patients with CTX. Such a mechanism also fits well with the observation that treatment with chenodeoxycholic acid, which normalizes the level of the bile acid precursor, results in a reduction of cholestanol-containing xanthomas even in the brain.
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Affiliation(s)
- Ute Panzenboeck
- Institute of Pathophysiology, Center of Molecular Medicine, Medical University of Graz, Graz, Austria, and Division of Clinical Chemistry, Karolinska University Hospital, Karolinska Institutet, Huddinge, Sweden
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Affiliation(s)
- G Salen
- Department of Medicine, University of Medicine and Dentistry-New Jersey Medical School, Newark 07103, USA
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Nikkilä K, Höckerstedt K, Miettinen TA. Serum and hepatic cholestanol, squalene and noncholesterol sterols in man: a study on liver transplantation. Hepatology 1992; 15:863-70. [PMID: 1568728 DOI: 10.1002/hep.1840150519] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Serum noncholesterol sterols indicate overall cholesterol metabolism in a variety of experimental and clinical conditions. In patients with advanced primary biliary cirrhosis serum cholestanol, a 5 alpha-derivative of cholesterol, is markedly increased, and cholesterol precursors, which are indicators of cholesterol synthesis, are clearly reduced, as is the ratio of plant sterols (campesterol/sitosterol). Therefore these variables were studied in the livers and sera of 23 patients undergoing liver transplantation (16 patients with chronic liver disease, 4 with acute liver failure and 3 receiving second liver) and in 10 healthy controls. A most striking finding was the markedly high liver and serum levels of cholestanol in patients with chronic end-stage liver disease, a finding specific for cholestanol but not for other sterols. Of the cholesterol precursor sterols, lathosterol exhibited low contents in both the serum and liver of the cirrhotic patient group, supposedly reflecting decreased cholesterol synthesis. In contrast to the largely similar levels of noncholesterol sterols in serum and liver and the positive correlations between the two sources, the serum squalene levels were markedly lower than the hepatic levels, with a negative correlation between the serum and the liver, suggesting that serum squalene content poorly reflects cholesterol synthesis. In contrast to campesterol, serum and liver sitosterol tended to show increases, and the serum and hepatic campesterol/sitosterol ratios were lower in the chronic liver disease patients than in the controls, probably because of the more consistently impaired biliary elimination of sitosterol in those patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- K Nikkilä
- Second Department of Medicine, University of Helsinki, Finland
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Nguyen LB, Cobb M, Shefer S, Salen G, Ness GC, Tint GS. Regulation of cholesterol biosynthesis in sitosterolemia: effects of lovastatin, cholestyramine, and dietary sterol restriction. J Lipid Res 1991. [DOI: 10.1016/s0022-2275(20)41897-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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11
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Kim KS, Kano K, Kasama T, Ishii Y, Yamashita H, Seyama Y. Effects of cholestanol feeding on corneal dystrophy in mice. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1085:343-9. [PMID: 1911869 DOI: 10.1016/0005-2760(91)90139-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A cholestanol-enriched diet administered for 8 months to BALB/c mice produced in 20% two kinds of corneal opacities resembling calcific band keratopathy and Schnyder's crystalline dystrophy in humans. The concentrations of cholestanol in serum, liver and cornea of the corneal opacity bearing mice were 30-40-times higher than those of normal mice. On the other hand, brain cholestanol level increased only 7-times in the opacity group as compared with that of control group. There was no significant difference in the cholesterol concentrations of serum and several tissues among opacity, non-opacity and the control group. The crystal particles were observed between epithelial basement membrane and superficial stroma by the electron microscopy. Energy dispersive analysis of the particles revealed that the deposits were composed principally of calcium and phosphorus with other crystalline materials, which was presumed to be cholestanol. These results suggest that the cholestanol may deposit in the cornea from elevated serum levels. Deposition of cholestanol in cornea and related area may be a cause of corneal dystrophy in CTX.
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Affiliation(s)
- K S Kim
- Department of Physiological Chemistry and Nutrition, Faculty of Medicine, University of Tokyo, Japan
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12
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Nguyen LB, Salen G, Shefer S, Tint GS, Shore V, Ness GC. Decreased cholesterol biosynthesis in sitosterolemia with xanthomatosis: diminished mononuclear leukocyte 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and enzyme protein associated with increased low-density lipoprotein receptor function. Metabolism 1990; 39:436-43. [PMID: 2325562 DOI: 10.1016/0026-0495(90)90260-j] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We investigated the mechanism for reduced cholesterol biosynthesis in sitosterolemia with xanthomatosis. The conversion of acetate to cholesterol and total and active hydroxymethylglutaryl (HMG) coenzyme A (CoA) reductase activities, enzyme protein mass, and catalytic efficiency were related to low-density lipoprotein (LDL) receptor function in freshly isolated mononuclear leukocytes collected at 9 AM after a 12-hour fast from two affected sisters and 12 control subjects. Active HMG-CoA reductase activity was determined in mononuclear leukocyte microsomes prepared and assayed in the presence of sodium fluoride, while total HMG-CoA reductase activity was determined in the absence of the phosphatase inhibitor. Enzyme protein was assayed using rabbit polyclonal anti-rat liver microsomal HMG-CoA reductase serum. The rates at which [14C]acetate was transformed to cholesterol by sitosterolemic mononuclear leukocytes were decreased 29% and 41%, respectively, compared with the mean value for mononuclear leukocytes from 12 control subjects. Similarly, total HMG-CoA reductase activities were 71% and 68% lower in sitosterolemic mononuclear leukocyte microsomes and were associated with 62% and 65% less enzyme protein than the mean for the control microsomal preparations. This marked decrease in HMG-CoA reductase protein mass in sitosterolemic microsomes was partially compensated for by an increase in the proportion of active enzyme. Sitosterolemic plasma and mononuclear leukocyte cholesterol concentrations were not significantly different from control values, although total sterol levels were increased about 20% because of abundant plant sterols. In contrast, receptor-mediated LDL degradation by sitosterolemic mononuclear leukocytes was increased 50% over control.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- L B Nguyen
- Department of Medicine, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark
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Salen G, Shore V, Tint GS, Forte T, Shefer S, Horak I, Horak E, Dayal B, Nguyen L, Batta AK. Increased sitosterol absorption, decreased removal, and expanded body pools compensate for reduced cholesterol synthesis in sitosterolemia with xanthomatosis. J Lipid Res 1989. [DOI: 10.1016/s0022-2275(20)38259-6] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Miettinen TA, Tilvis RS, Kesäniemi YA. Serum cholestanol and plant sterol levels in relation to cholesterol metabolism in middle-aged men. Metabolism 1989; 38:136-40. [PMID: 2913464 DOI: 10.1016/0026-0495(89)90252-7] [Citation(s) in RCA: 165] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Serum cholestanol was studied in relation to fecal cholestanol excretion and cholesterol metabolism in a random middle-aged population of 61 men. The serum concentrations of cholestanol ranged from 1.6 to 10.8 mumol/L and were positively correlated with those of serum total LDL and HDL cholesterol. In terms of millimole per mole of cholesterol, these correlations disappeared; inverse associations were found with VLDL cholesterol and triglyceride levels, the P/S ratio of dietary fat, and the amount of fecal plant sterols, but not with fecal cholestanol. The serum contents of cholestanol (1) were also closely positively associated with those of serum plant sterols (campesterol and sitosterol) and fractional cholesterol absorption, (2) were inversely related to the fecal excretion of neutral sterols and cholesterol synthesis which were measured either by the sterol balance technique or serum cholesterol precursor sterols (desmosterol and lathosterol), and (3) were unrelated to bile acid synthesis. Fecal cholestanol (mean = 12.5 mg/d) was (1) clearly higher than the dietary cholestanol intake (less than 2 mg/d), (2) unrelated to serum cholestanol, and (3) positively correlated with the intestinal cholesterol (dietary plus endogenous) flux as well as fecal plant sterols, neutral sterols, and bacterial products of cholesterol. The study emphasizes that, in normal men, high serum cholestanol levels reflect high efficiency of intestinal sterol absorption and low cholesterol synthesis. Thus, the changes in the serum contents of cholestanol are parallel with those of plant sterols and opposite to those of cholesterol precursor sterols.
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Affiliation(s)
- T A Miettinen
- Second Department of Medicine, University of Helsinki, Finland
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15
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Shefer S, Salen G, Nguyen L, Batta AK, Packin V, Tint GS, Hauser S. Competitive inhibition of bile acid synthesis by endogenous cholestanol and sitosterol in sitosterolemia with xanthomatosis. Effect on cholesterol 7 alpha-hydroxylase. J Clin Invest 1988; 82:1833-9. [PMID: 3143743 PMCID: PMC442761 DOI: 10.1172/jci113799] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The 7 alpha-hydroxylation of two cholesterol analogues, sitosterol and cholestanol, and their effect on the 7 alpha-hydroxylation of cholesterol were measured in rat and human hepatic microsomes. In untreated rat liver microsomes, the 7 alpha-hydroxylation of cholesterol was higher than that of cholestanol (1.4-fold) and sitosterol (30-fold). After removal of endogenous sterols from the microsomes by acetone treatment, the 7 alpha-hydroxylation of cholesterol was similar to that of cholestanol and only fourfold higher than that of sitosterol. Cholestanol and sitosterol competitively inhibited cholesterol 7 alpha-hydroxylase in both rat and human liver microsomes, with cholestanol the more potent inhibitor. Patients with sitosterolemia with xanthomatosis, who have elevated microsomal cholestanol and sitosterol, showed reduced cholesterol 7 alpha-hydroxylase activity relative to the activity in control subjects (13.9 and 14.7 vs. 20.3 +/- 0.9 pmol/nmol P-450 per min, P less than 0.01). Enzyme activity in these patients was 40% higher when measured in microsomes from which competing sterols had been removed. Ileal bypass surgery in one sitosterolemic patient decreased plasma cholestanol and sitosterol concentrations and resulted in a 30% increase in hepatic microsomal cholesterol 7 alpha-hydroxylase activity. Cholesterol 7 alpha-hydroxylase appears to have a specific apolar binding site for the side chain of cholesterol and is affected by the presence of cholestanol and sitosterol in the microsomal substrate pool. Reduced bile acid synthesis in sitosterolemia with xanthomatosis may be related to the inhibition of cholesterol 7 alpha-hydroxylase activity by endogenous cholesterol analogues.
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Affiliation(s)
- S Shefer
- Department of Medicine, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark 07103
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16
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Koivisto PV, Miettinen TA. Plasma and biliary cholestanol related to steroid metabolism in familial hypercholesterolemia patients with and without ileal exclusion. Clin Chim Acta 1988; 174:197-205. [PMID: 3133140 DOI: 10.1016/0009-8981(88)90386-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Plasma cholestanol is increased in cerebrotendinous xanthomatosis and in sitosterolemia with xanthomatosis. We measured plasma and biliary cholestanol in heterozygous familial hypercholesterolemia patients with (n = 10) and without (n = 12) ileal exclusion. In the unoperated patients plasma cholestanol concentration (12.9 mumol/l) and content (1.2 mmol/mol cholesterol) were slightly higher than in the nonhypercholesterolemic control subjects studied by us. Ileal exclusion had lowered plasma cholestanol concentration but only in proportion to the lowering of plasma cholesterol concentration, and plasma cholestanol content (mmol/mol cholesterol) was similar in the operated and unoperated subjects. Plasma and biliary cholestanol contents were positively associated. In the unoperated patients the fractional cholesterol absorption and plasma plant sterols, also reflecting sterol absorption, were positively correlated with plasma cholestanol content. Our study suggests, that plasma cholestanol is slightly elevated in familial hypercholesterolemia and that, in addition to plasma lipoprotein level, sterol absorption is important in the regulation of plasma cholestanol level. Ileal exclusion decreases plasma cholestanol in proportion to the decrement in the plasma cholesterol concentration.
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Affiliation(s)
- P V Koivisto
- Second Department of Medicine, University of Helsinki, Finland
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17
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Boberg KM, Skrede S. Content of sitosterol, cholestanol, and cholesterol in very low density lipoproteins of rat liver perfusate. Scand J Gastroenterol 1988; 23:442-8. [PMID: 3381065 DOI: 10.3109/00365528809093892] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Sterol specificity in synthesis of very low density lipoproteins in the rat liver was studied by liver perfusion after injection in vivo of sterols as double isotopes. The amounts of sterols recovered in the very low density lipoprotein fraction of the perfusate were compared with the microsomal contents, using both double isotope ratio technique and quantitation by gas chromatography. The secretion of sitosterol and cholestanol was 0.72 and 0.88 of that of cholesterol, respectively. Variations of microsomal sterol concentrations did not affect the principal results. Relative to cholesterol, one-third more of injected sitosterol was present in the liver after 24 h. Sitosterol was excreted in the bile at one-fourth the rate of cholesterol and to a larger extent as free sterol compared with cholesterol.
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Affiliation(s)
- K M Boberg
- Institute of Clinical Biochemistry, University of Oslo, Norway
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18
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Salen G, Berginer V, Shore V, Horak I, Horak E, Tint GS, Shefer S. Increased concentrations of cholestanol and apolipoprotein B in the cerebrospinal fluid of patients with cerebrotendinous xanthomatosis. Effect of chenodeoxycholic acid. N Engl J Med 1987; 316:1233-8. [PMID: 3106810 DOI: 10.1056/nejm198705143162002] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We investigated the effect of chenodeoxycholic acid on cerebrospinal fluid sterol and protein composition in six patients with cerebrotendinous xanthomatosis, a progressive neurologic disease, and in 11 control subjects. In the cerebrospinal fluid from the controls, the mean (+/- SD) levels of cholesterol and cholestanol were 400 +/- 300 and 4 +/- 7 micrograms per deciliter, respectively. The levels were almost 1.5 and 20 times higher in cerebrospinal fluid from untreated patients with cerebrotendinous xanthomatosis. Cholestanol levels were also markedly elevated in the plasma of untreated patients, but their plasma cholesterol levels (215 +/- 61 mg per deciliter) were not different from control values. Treatment with chenodeoxycholic acid reduced cerebrospinal fluid cholesterol by 34 percent and cholestanol threefold. Plasma cholestanol levels also decreased sharply. Normal cerebrospinal fluid contained small quantities of albumin, apolipoproteins, and lecithin:cholesterol acyltransferase. In cerebrospinal fluid from untreated patients with cerebrotendinous xanthomatosis, immunoreactive apolipoprotein B or apolipoprotein B fragment was increased about 100-fold and albumin about 3.5-fold; apolipoprotein AI, apolipoprotein D, and lecithin:cholesterol acyltransferase were 1.5 to 3 times more concentrated. Apolipoprotein AIV and apolipoprotein E concentrations were comparable to those in controls, and apolipoprotein AII was considerably decreased. During treatment, the concentrations of albumin and apolipoproteins AI and B declined. These results suggest that increased cerebrospinal fluid sterols are derived from plasma lipoproteins by means of a defective blood-brain barrier in patients with cerebrotendinous xanthomatosis. Therapy with chenodeoxycholic acid reestablished selective permeability of the blood-brain barrier and normalized the concentrations of sterol and apolipoprotein in the cerebrospinal fluid.
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Lee SP, Tasman-Jones C, Carlisle VF. Oleic acid-induced cholelithiasis in the rabbit: conversion of dietary oleic acid to cholestanol as a cause of calcium-bile salt gallstones. Hepatology 1987; 7:529-34. [PMID: 3570164 DOI: 10.1002/hep.1840070319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Rabbits fed a diet rich in oleic acid develop gallstones consisting of calcium salts of (5 alpha)-glyco-allodeoxycholic acid. To study the metabolic pathway of oleic acid, we followed the changes in plasma, hepatic and biliary lipids in this animal model. In addition, to also determine the role played by intestinal microflora on biliary lipid metabolism, we added kanamycin to the oleic acid diet. Oleic acid-fed rabbits rapidly developed hypercholesterolemia. This was associated with an increase in liver 3-hydroxy-3-methylglutaryl coenzyme A reductase activity, accumulation of cholesterol as well as cholestanol in the liver and progressive saturation of cholesterol in bile. [14C]oleic acid fed orally to rabbits was recovered in liver extracts as both cholesterol and cholestanol. With oleic acid feeding, there was a progressive increase in glyco-allodeoxycholic acid culminating in the formation of gallstones. Kanamycin supplement to the oleic acid diet resulted in the same changes in plasma and hepatic sterol metabolism compared with oleic acid-fed rabbits. There was, however, a striking difference in the biliary bile acid profile. Kanamycin supplementation dramatically reduced the proportion of 5 alpha-dihydroxy bile acids, increased the proportion of 5 beta-trihydroxy bile acids and completely abolished gallstone formation. We postulate that, in the rabbit, oleic acid is used as a carbon source for cholesterol synthesis, and a high oleic acid diet increases hepatic cholesterogenesis. Hepatic cholesterol is then metabolized to form cholestanol, followed by (5 alpha)-glyco-allocholic acid which is secreted into bile and transformed by gut bacteria to form (5 alpha)-allodeoxycholic acid. Kanamycin abolished gallstone formation by inhibiting intestinal bacterial dehydroxylation.
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Buchmann MS, Clausen OP. Effects of cholestanol feeding and cholestyramine treatment on the tissue sterols in the rabbit. Lipids 1986; 21:738-43. [PMID: 3821387 DOI: 10.1007/bf02535404] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Rabbits were fed diets enriched with cholestanol or cholesterol (3.5 g/wk) for 4-12 weeks. During cholestanol feeding, the concentration of cholestanol in blood serum, liver, heart and aorta increased 15-30 times. In serum and liver, the concentration of cholesterol also increased. Cholestanol-fed rabbits developed inflammatory changes in the liver, with proliferation of small bile ducts. Liver tests were only slightly abnormal. Morphological atherosclerosis of the aorta was only occasionally seen in rabbits receiving cholestanol for eight weeks or less. During cholesterol feeding, the amounts of cholesterol in different tissues increased dramatically, most in the aorta. Morphological atherosclerosis in the aorta was found in all rabbits fed cholesterol-enriched diets for more than four weeks. Brain cholestanol was doubled in rabbits fed cholestanol for eight weeks, whereas brain sterols did not change significantly during cholesterol feeding. After an additional regression period with cholestyramine for eight weeks, the increased content of cholestanol in the brain was unchanged in cholestanol-fed rabbits. These observations are discussed in relation to the cholestanolosis of the brain that develops in the rare inherited human disease cerebrotendinous xanthomatosis.
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Yokohama H, Ohtsuka I, Shiojiri H, Katayama K, Ishikawa S. A high-performance liquid chromatographic method for the assay of cholesterol 7 alpha-hydroxylase activity. Anal Biochem 1986; 157:186-90. [PMID: 3766961 DOI: 10.1016/0003-2697(86)90212-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A high-performance liquid chromatographic method has been developed for the measurement of cholesterol 7 alpha-hydroxylase activity in liver microsomes. 7 alpha-Hydroxycholesterol generated from endogenous cholesterol was derivatized with anthroyl 1-carbonitrile, chromatographed on a reverse-phase column, and detected fluorometrically. The detection limit of 7 alpha-hydroxycholesterol was 1 ng/tube. The cholesterol 7 alpha-hydroxylase activity in rat liver microsomes was assayed by this method, and the effects of some detergents and of the addition of exogenous cholesterol together with detergents on the enzyme activity were investigated. The endogenous 7 alpha- and 7 beta-hydroxycholesterol could be also measured by this method.
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Lee SP, Tasman-Jones C, Carlisle V. Oleic acid-induced cholelithiasis in rabbits. Changes in bile composition and gallbladder morphology. THE AMERICAN JOURNAL OF PATHOLOGY 1986; 124:18-24. [PMID: 3728645 PMCID: PMC1888183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Feeding oleic acid to rabbits resulted in a progressive rise in bile concentration of allodeoxycholic acid, expansion of the bile salt pool, and depression of de novo hepatic bile acid synthesis. There was also an increase in cholesterol saturation in bile. The gallstones that formed contained traces of cholesterol but were composed mainly of salts of allodeoxycholic acid. The data suggest that oleic acid feeding results in increased rate of cholestanol and allodeoxycholic acid metabolism. Morphologically, these biochemical events were accompanied by early reactive changes in the gallbladder epithelium characterized by marked increase in cell proliferation and mucus hypersecretion. In addition, there was the early formation of interepithelial cell vacuoles and, later, Rokitansky-Aschoff sinuses. These cellular reactions reflect the dramatic and important changes that take place in the gallbladder before gallstone formation.
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Björkhem I, Buchmann MS, Skrede S. On the structural specificity in the regulation of the hydroxymethylglutaryl-CoA reductase and the cholesterol-7 alpha-hydroxylase in rats. Effects of cholestanol feeding. BIOCHIMICA ET BIOPHYSICA ACTA 1985; 835:18-22. [PMID: 3924107 DOI: 10.1016/0005-2760(85)90024-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The effect of feeding 2% cholestanol or cholesterol on cholesterol-7 alpha-hydroxylase activity and hydroxymethylglutaryl (HMG)-CoA reductase activity was studied in rats. The rate of 7 alpha-hydroxylation of a trace amount of labelled cholesterol increased by about 80% after the cholestanol feeding, whereas the 7 alpha-hydroxylation of endogenous microsomal cholesterol increased by about 40%. The latter conversion was measured with an accurate technique based on isotope dilution-mass spectrometry. After cholesterol feeding, the corresponding figures were about 50 and 60%, respectively. The cholestanol feeding had no significant effect on the HMG-CoA reductase activity, whereas the cholesterol feeding decreased the activity by about 80%. From the results obtained, it is concluded that the increased 7 alpha-hydroxylation observed after cholesterol feeding can not be explained only by a simple expansion of the substrate pool. The similar effect of both cholesterol and cholestanol on the cholesterol 7 alpha-hydroxylase activity and the diverging effect on the HMG-CoA reductase activity show that there is no coupling between cholesterol synthesis and degradation under the conditions employed. The lack of effect of cholestanol on the HMG-CoA reductase activity indicates a high structural specificity of the receptor involved in regulation of the enzyme. If a receptor mechanism is involved in the stimulation of the cholesterol-7 alpha-hydroxylase by cholesterol and cholestanol, these receptor(s) must be different from those involved in the regulation of the HMG-CoA reductase.
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