51
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Dergunov AD, Rosseneu M. The significance of apolipoprotein E structure to the metabolism of plasma triglyceride-rich lipoproteins. BIOLOGICAL CHEMISTRY HOPPE-SEYLER 1994; 375:485-95. [PMID: 7811390 DOI: 10.1515/bchm3.1994.375.8.485] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In this paper we analyse the structural organization of human apolipoprotein E (apoE) at the surface of triglyceride (TG)-rich lipoproteins, in relation to the metabolic pathway of these particles. ApoE acts as a receptor-binding ligand at the surface of chylomicrons and VLDL (very low density lipoproteins). The degree of exposure of apoE at the surface of lipoproteins and its affinity for the receptor both determine the uptake and catabolism of these lipoproteins. ApoE and/or apoB100, the major apolipoprotein constituent of LDL, contribute to the interaction of lipoproteins with five different cellular receptors: 1) the low density lipoprotein (LDL) receptor; 2) the LDL receptor-related protein (LRP); 3) the macrophage receptor for hypertriglyceridemic VLDL; 4) the scavenger receptor; 5) the VLDL receptor. The degree of exposure of apoE at the surface of normo- and hyperlipidemic VLDL can modulate their uptake by the LDL receptor. Normolipidemic VLDL are poorly recognized by the LDL receptor whereas hypertriglyceridemic VLDL are cleared more efficiently through this pathway. On the other hand, the extent of apoE self-association, which is dependent upon the degree of hydrolysis of the TG-rich particles, can control their interaction with the LDL-receptor related protein. The lateral organization of apoE at the surface of TG-rich particles, its interaction with other apoproteins and its extent of self-association might therefore be important factors in the clearance of these lipoproteins. Finally, structural defects of apoE might result in an impaired interaction of apoE-containing lipoproteins with these receptors and lead to the development of atherogenic dyslipidemias.
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Affiliation(s)
- A D Dergunov
- Biochemistry Department, National Research, Centre for Preventive Medicine, Moscow, Russia
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52
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Fazio S, Horie Y, Simonet W, Weisgraber K, Taylor J, Rall S. Altered lipoprotein metabolism in transgenic mice expressing low levels of a human receptor-binding-defective apolipoprotein E variant. J Lipid Res 1994. [DOI: 10.1016/s0022-2275(20)41192-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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53
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de Knijff P, van den Maagdenberg AM, Frants RR, Havekes LM. Genetic heterogeneity of apolipoprotein E and its influence on plasma lipid and lipoprotein levels. Hum Mutat 1994; 4:178-94. [PMID: 7833947 DOI: 10.1002/humu.1380040303] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Apolipoprotein E (apoE) is one of the major protein constituents of chylomicron and very-low-density lipoprotein (VLDL) remnants and plays a central role as a ligand in the receptor-mediated uptake of these particles by the liver. Including the most common variant, apoE3, 30 apoE variants have been characterized. At present, 14 apoE variants have been found to be associated with familial dysbetalipoproteinemia, a genetic lipid disorder characterized by elevated plasma cholesterol and triglyceride levels and an increased risk for atherosclerosis. Seven apoE variants were found to be associated with other forms of hyperlipoproteinemia. This report presents an overview of all currently known apoE variants and their effects on lipoprotein metabolism.
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Affiliation(s)
- P de Knijff
- TNO Institute of Prevention and Health Research, Gaubius Laboratory, Leiden, The Netherlands
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54
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Affiliation(s)
- K H Weisgraber
- Gladstone Institute of Cardiovascular Disease, San Francisco, California 94141-9100
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55
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Ruzicka V, März W, Russ A, Fisher E, Mondorf W, Gross W. Characterization of the gene for apolipoprotein E5-Frankfurt (Gln81->Lys, Cys112->Arg) by polymerase chain reaction, restriction isotyping, and temperature gradient gel electrophoresis. Electrophoresis 1993; 14:1032-7. [PMID: 8125051 DOI: 10.1002/elps.11501401164] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A new apolipoprotein (apo) E variant, apoE5-Frankfurt, was identified in a 43-year-old male with moderate hypercholesterolemia. On isoelectric focusing in an immobilized pH gradient, apoE5-Frankfurt migrated to a position more cathodic than apoE4 (Cys112->Arg). On sodium dodecyl sulfate-gel electrophoresis, its apparent molecular weight could not be distinguished from that of the three common apoE isoforms (E2, E3 and E4). Restriction isotyping with CfoI (HhaI) showed that apoE5-Frankfurt had arginine in positions 112 and 158 of the mature protein, suggesting that the mutation accounting for the additional positive charge had occurred in an epsilon 4 allele. The third and the fourth exon of the apoE gene were amplified using the polymerase chain reaction and analyzed by temperature gradient gel electrophoresis. This suggested that there were two mutations in the fourth exon of the mutant allele. Cloning and sequencing disclosed that, apart from the exchange of arginine for cysteine in position 112, a C to A substitution replaced glutamine (CAA) in position 81 by lysine (AAA).
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Affiliation(s)
- V Ruzicka
- Gustav Embden-Center of Biological Chemistry, Johann Wolfgang Goethe-University, Frankfurt am Main, Germany
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56
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Fazio S, Lee YL, Ji ZS, Rall SC. Type III hyperlipoproteinemic phenotype in transgenic mice expressing dysfunctional apolipoprotein E. J Clin Invest 1993; 92:1497-503. [PMID: 8376602 PMCID: PMC288296 DOI: 10.1172/jci116728] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Transgenic mice were prepared that expressed a dysfunctional apo E variant, apo E (Arg-112, Cys-142), which is associated with dominant inheritance of type III hyperlipoproteinemia (type III HLP) in humans. Among eight founder mice, plasma apo E (Arg-112, Cys-142) levels varied 100-fold and directly correlated with plasma cholesterol and triglyceride levels. On a normal chow diet, mice expressing high levels (> 70 mg/dl) of the dysfunctional apo E had grossly elevated plasma lipids, with cholesterol levels of up to 410 mg/dl and triglyceride levels of up to 1,210 mg/dl. Upon agarose electrophoresis, plasma from these mice demonstrated beta-very low density lipoproteins (beta-VLDL). Mice expressing low (< 2.5 mg/dl) or intermediate (21 mg/dl) levels of the apo E variant had much less severe hyperlipidemia and did not have beta-VLDL. Although the transgenic mouse beta-VLDL were enriched in cholesteryl esters compared with normal mouse VLDL, they were not as cholesterol enriched as human beta-VLDL from type III HLP subjects. Transgenic mouse beta-VLDL injected into normal mice were cleared from plasma at a significantly slower rate than normal mouse VLDL, demonstrating the impaired catabolism of beta-VLDL. Thus, transgenic mice expressing high levels of the dysfunctional apo E (Arg-112, Cys-142) variant have many characteristics of the human type III HLP phenotype and appear to be a suitable animal model for this disorder.
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Affiliation(s)
- S Fazio
- Gladstone Institute of Cardiovascular Disease, University of California, San Francisco 94141-9100
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57
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van den Maagdenberg AM, Weng W, de Bruijn IH, de Knijff P, Funke H, Smelt AH, Gevers Leuven JA, van't Hooft FM, Assmann G, Hofker MH. Characterization of five new mutants in the carboxyl-terminal domain of human apolipoprotein E: no cosegregation with severe hyperlipidemia. Am J Hum Genet 1993; 52:937-46. [PMID: 8488843 PMCID: PMC1682049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Assessment of the apolipoprotein E (apoE) phenotype by isoelectric focusing of both hyperlipidemic and normolipidemic individuals identified five new variants. All mutations were confined to the downstream part of the APOE gene by using denaturing gradient gel electrophoresis (DGGE). Sequence analysis revealed five new mutations causing unique amino acid substitutions in the carboxyl-terminal part of the protein containing the putative lipid-binding domain. Three hyperlipoproteinemic probands were carriers of the APOE*2(Val236-->Glu) allele, the APOE*3(Cys112-->Arg; Arg251-->Gly) allele, or the APOE*1(Arg158-->Cys; Leu252-->Glu) allele. DGGE of the region encoding the receptor-binding domain was useful for haplotyping the mutations at codons 112 and 158. Family studies failed to demonstrate cosegregation between the new mutations and severe hyperlipoproteinemia, although a number of carriers for the APOE*3(Cys112-->Arg; Arg251-->Gly) allele and the APOE*1(Arg158-->Cys; Leu252-->Glu) allele expressed hypertriglyceridemia and/or hypercholesterolemia. Two other mutant alleles, APOE*4-(Cys112-->Arg; Arg274-->His) and APOE*4+(Ser296-->Arg), were found in normolipidemic probands. The lack of cosegregation of these new mutations with severe hyperlipoproteinemia suggests that these mutations do not exert a dominant effect on the functioning of apoE.
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58
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Wenham PR, McDowell IF, Hodges VM, McEneny J, O'Kane MJ, Davies RJ, Nicholls DP, Trimble ER, Blundell G. Rare apolipoprotein E variant identified in a patient with type III hyperlipidaemia. Atherosclerosis 1993; 99:261-71. [PMID: 8503953 DOI: 10.1016/0021-9150(93)90028-s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We report a rare apolipoprotein E variant in an Irish female with Type III hyperlipidaemia who has the phenotype E2E1 as determined by isoelectric focusing. Sequence analysis of the apolipoprotein E gene from the proband and from four other family members, using DNA amplified by the polymerase chain reaction, demonstrated the presence of a point mutation in the common epsilon 2 allele with a G-->A transition at nucleotide 3791. This was confirmed by digestion with the restriction endonuclease TaqI, which cuts at a new site within the apolipoprotein E gene, created by the base change. This mutation results in a substitution of aspartic acid for glycine at position 127 of the mature protein. We believe this to be the first description of this apolipoprotein E variant in a family from the British Isles. The mutation appears to be 'recessive' with respect to the expression of Type III hyperlipidaemia, although it may be somewhat more potent in this regard than the parent epsilon 2 allele. The Type III hyperlipidaemia is responsive to treatment with diet and gemfibrozil.
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Affiliation(s)
- P R Wenham
- Department of Clinical Biochemistry, Western General Hospital, Edinburgh, UK
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59
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Fazio S, Horie Y, Weisgraber KH, Havekes LM, Rall SC. Preferential association of apolipoprotein E Leiden with very low density lipoproteins of human plasma. J Lipid Res 1993. [DOI: 10.1016/s0022-2275(20)40736-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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60
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Zannis VI, Kardassis D, Zanni EE. Genetic mutations affecting human lipoproteins, their receptors, and their enzymes. ADVANCES IN HUMAN GENETICS 1993; 21:145-319. [PMID: 8391199 DOI: 10.1007/978-1-4615-3010-7_3] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- V I Zannis
- Department of Medicine, Housman Medical Research Center, Boston University Medical Center, Massachusetts 02118
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61
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Feussner G, Funke H, Weng W, Assmann G, Lackner KJ, Ziegler R. Severe type III hyperlipoproteinemia associated with unusual apolipoprotein E1 phenotype and epsilon 1/'null' genotype. Eur J Clin Invest 1992; 22:599-608. [PMID: 1360898 DOI: 10.1111/j.1365-2362.1992.tb01511.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A 60-year-old white male (KH) was diagnosed to suffer from severe type III hyperlipoproteinemia (HLP) and premature cardiovascular disease. Biochemical analysis revealed an unusual apolipoprotein (apo) E phenotype and genotype. All clinical characteristics of type III HLP were present in the patient. His very low density lipoprotein (VLDL) cholesterol to plasma triglyceride (TG) ratio was elevated at 0.97 without therapy which is unusually high (normal ratio about 0.18). By contrast his plasma apo E level was only moderately elevated (6.8 mg dl-1). The patient's apo E migrated in the apo E1 position on isoelectric focusing gels. Chemical modification with cysteamine and treatment with neuraminidase confirmed the presence of two cysteine residues in the patient's apo E and a normal sialylation pattern. Pedigree analysis suggested that the patient was a compound heterozygote with one apo epsilon 1 allele and another allele whose product did not appear in the plasma compartment ('null' allele). Direct sequencing of polymerase chain reaction (PCR) amplified segments of the apo E gene as well as restriction fragment length polymorphism (RFLP) analysis with the endonuclease Taq I identified an adenosine for guanosine (G-->A) exchange in the second base of codon 127 that is predictive for an Asp for Gly substitution in the encoded apo E amino acid sequence. This mutation is the structural basis for the apo E1 isoform identified upon isoelectric focusing. Five other family members are also carriers of the mutant apo epsilon 1 allele. Two of those were hyperlipidemic and exhibited biochemical characteristics of type III HLP. A second mutation, a deletion of a G in codon 31, is predictive for a reading frameshift that encodes for a premature stop in codon 60. Our inability to identify the product of a second apo E allele in the plasma of the patient and two other members of the KH family corresponds with the heterozygous presence of this mutation in the affected individuals. Both relatives (like the index case) had an increased VLDL cholesterol to plasma TG ratio, which indicates the presence of cholesterol-enriched VLDL particles. We propose that the single base deletion in the apo E gene which is the cause of a non-functional 'null' allele in addition to a probably dominant apo E1 (Gly127-->Asp, Arg158-->Cys) variant of late or incomplete penetrance are the primary genetic defects in this kindred leading to severe dysbetalipoproteinemia.
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Affiliation(s)
- G Feussner
- Medizinische Universitätsklinik Heidelberg, Germany
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62
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Lohse P, Rader D, Brewer HB. Heterozygosity for apolipoprotein E-4Philadelphia(Glu13—-Lys, Arg145—-Cys) is associated with incomplete dominance of type III hyperlipoproteinemia. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)42261-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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63
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Abstract
Apolipoprotein E plays a central role in lipoprotein metabolism by serving as a ligand for the binding of lipoproteins to lipoprotein receptors. Both common and rare variants of apoE have been described. The common variants apoE2 and apoE4 have a significant impact on interindividual variation of lipid and lipoprotein levels in normal subjects. The common variant apoE2 and more than half a dozen rare variants are defective in binding to the low-density lipoprotein (LDL) receptor, and all are causally associated with the lipid disorder type III hyperlipoproteinaemia (HLP). The mode of inheritance of the disorder can be either dominant or recessive, depending on the particular mutation(s) in apoE, although the mechanisms involved are not fully understood. The common variant apoE4 and other rare variants have been reported to be associated with a variety of other lipoprotein disorders, but a causal link has not been established.
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Affiliation(s)
- S C Rall
- Gladstone Institute of Cardiovascular Disease, University of California, San Francisco
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64
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Horie Y, Fazio S, Westerlund JR, Weisgraber KH, Rall SC. The functional characteristics of a human apolipoprotein E variant (cysteine at residue 142) may explain its association with dominant expression of type III hyperlipoproteinemia. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)46040-1] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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65
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Jones PJ, Dendy SM, Frohlich JJ, Leitch CA, Schoeller DA. Cholesterol and triglyceride fatty acid synthesis in apolipoprotein E2-associated hyperlipidemia. ARTERIOSCLEROSIS AND THROMBOSIS : A JOURNAL OF VASCULAR BIOLOGY 1992; 12:106-13. [PMID: 1731853 DOI: 10.1161/01.atv.12.1.106] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
To investigate whether increased endogenous lipogenesis contributes to elevated plasma lipid levels in individuals with apolipoprotein (apo) E2-associated hyperlipidemia (E2-HL), plasma pool cholesterol and triglyceride fatty acid syntheses were measured in subjects with E2-HL and in those with normal lipid levels. Subjects were given a priming dose of deuterium oxide (D2O) followed by maintenance doses over 48 hours. During the first 24 hours, subjects consumed prepared meals, whereas during the 24-48 hour interval, they consumed water only. Blood samples were drawn every 12 hours, and cholesterol and triglyceride fatty acid formation rates were determined from the change in deuterium enrichment. The free cholesterol fractional synthesis rate over 0-24 hours of E2-HL subjects (0.057 +/- 0.010 day-1, mean +/- SEM) was not significantly different from that of normolipidemics (0.075 +/- 0.005 day-1). Calculated cholesterol net synthesis was not different between the two groups (0.56 +/- 0.07 and 0.75 +/- 0.05 g/day, respectively). Mean free cholesterol synthesis for all subjects was higher in the fed (0-24 hour) compared with the fasted (24-48-hour) condition. Initial 12-hour triglyceride fatty acid fractional synthesis was significantly (p less than 0.01) increased in E2-HL subjects (0.143 +/- 0.012 day-1) compared with controls (0.082 +/- 0.0013 day-1). These findings suggest that in E2-HL, elevated plasma cholesterol levels are due to factors other than increased sterol synthesis, while higher de novo fatty acid synthesis contributes to the observed hypertriglyceridemia.
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Affiliation(s)
- P J Jones
- Division of Human Nutrition, University of British Columbia, Vancouver, Canada
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66
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de Knijff P, van den Maagdenberg AM, Stalenhoef AF, Leuven JA, Demacker PN, Kuyt LP, Frants RR, Havekes LM. Familial dysbetalipoproteinemia associated with apolipoprotein E3-Leiden in an extended multigeneration pedigree. J Clin Invest 1991; 88:643-55. [PMID: 1864973 PMCID: PMC295406 DOI: 10.1172/jci115349] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
By the careful screening of familial dysbetalipoproteinemic (FD) patients, five probands showing heterozygosity for the APOE*3-Leiden allele were found. Genealogical studies revealed that these probands share common ancestry in the 17th century. In a group of 128 family members, spanning three generations, 37 additional heterozygous APOE*3-Leiden gene carriers were detected. Although with a variable degree of severity, all carriers exhibited characteristics of FD such as (a) elevated levels of cholesterol in the very low density lipoprotein (VLDL) and intermediate density lipoprotein (IDL) fractions, (b) elevated ratios of cholesterol levels in these density fractions over total plasma levels of triglycerides, and (c) strongly increased plasma levels of apolipoprotein E (apoE). Multiple linear regression analysis revealed that most of the variability in expression of FD in APOE*3-Leiden allele carriers can be explained by age. Body mass index showed a less significant influence on the expression of FD. Gender had no effect on the expression in E*3-Leiden allele carriers, nor did it influence the age of onset of FD. In the group of APOE*3-Leiden allele carriers, we found that the E*2 allele enhances the expression of FD, whereas the E*4 allele had the opposite effect. Isoelectric focusing of plasma and of isolated VLDL, IDL, and high density lipoprotein density fractions showed that in E*3-Leiden allele carriers the apoE3-Leiden variant largely predominates over its normal apoE counterpart, especially in the VLDL and IDL density fractions. We conclude that in APOE*3-Leiden allele carriers FD is dominantly inherited with a high rate of penetrance, i.e., the presence of normally functioning apoE molecules in the plasma does not prevent the age-related expression of this disease.
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Affiliation(s)
- P de Knijff
- Institute of Ageing and Vascular Research, Netherlands Organization for Applied Scientific Research, Leiden
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67
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Lohse P, Mann W, Stein E, Brewer H. Apolipoprotein E-4Philadelphia (Glu13—-Lys,Arg145—-Cys). Homozygosity for two rare point mutations in the apolipoprotein E gene combined with severe type III hyperlipoproteinemia. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)99249-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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68
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Davignon J, Dallongeville J, Roederer G, Roy M, Fruchart JC, Kessling AM, Bouthillier D, Lussier-Cacan S. A phenocopy of type III dysbetalipoproteinemia occurring in a candidate family for a putative apo E receptor defect. Ann Med 1991; 23:161-7. [PMID: 1648930 DOI: 10.3109/07853899109148042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
On theoretical grounds, an apo E receptor defect should be manifested by the accumulation of lipoprotein remnants that are normally cleared by this receptor and cannot be processed by the normal apo B, E receptor (LDL-receptor). Furthermore, the defect should not be selective for a specific apo E phenotype since none of the isoforms would be cleared preferentially. Our search for such an occurrence led us to the discovery, in five members of a family of ten, of a unique dyslipoproteinemia mimicking type III. As in type III, plasma levels of cholesterol, triglycerides, VLDL-cholesterol, VLDL-triglycerides and apo E, as well as the VLDL-C/TG ratio, were high. LDL-cholesterol and HDL-cholesterol tended to be low. The clearance of plasma triglycerides after a fat load was impaired. Tubero-eruptive xanthomas, arcus corneae and manifestations of atherosclerosis were present in some individuals. In contrast to type III, the dyslipoproteinemia occurred in subjects bearing three different apo E phenotypes: E4/2, E4/3 and E3/2. VLDL-apo B levels were markedly increased, the VLDL-C/VLDL-B ratio was low and a double pre-beta band was present on lipoprotein electrophoresis. In spite of high apo E and borderline high apo CIII plasma levels, levels of the lipoprotein particles LpCIII:B and LpE:B, which characterize type III, were not raised. Rapid weight loss or treatment with a fibrate was observed to normalize the lipoprotein profile. It is surmised that the apo E-rich lipoprotein particles accumulating in this type III phenocopy with "hyperapoprebetalipoproteinemia" could be those that are normally cleared by an apo E receptor.
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Affiliation(s)
- J Davignon
- Clinical Research Institute of Montreal, Department of Medicine, University of Montreal, Canada
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69
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Mailly F, Xu CF, Xhignesse M, Lussier-Cacan S, Talmud PJ, Davignon J, Humphries SE, Nestruck AC. Characterization of a new apolipoprotein E5 variant detected in two French-Canadian subjects. J Lipid Res 1991. [DOI: 10.1016/s0022-2275(20)42048-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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70
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Indications for lipid-lowering drugs. Eur J Clin Pharmacol 1991. [DOI: 10.1007/bf03216280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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71
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72
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Abstract
The case of a 6-year-old girl with severe hyperlipoproteinemia and chronic renal failure that developed after hemolytic uremic syndrome (HUS) is reported. The patient was homozygous for apolipoprotein (apo) E2, and her very-low-density lipoprotein (VLDL)-cholesterol/serum-triglyceride (TG) ratio of 0.63 was unusually high. She was consistently diagnosed to have type III hyperlipoproteinemia (HLP). This is the first report of type III HLP in a child with chronic renal disease.
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Affiliation(s)
- G Feussner
- Department of Internal Medicine, University of Heidelberg, FRG
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73
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Weisgraber KH, Innerarity TL, Rall SC, Mahley RW. Atherogenic lipoproteins resulting from genetic defects of apolipoproteins B and E. Ann N Y Acad Sci 1990; 598:37-48. [PMID: 2248450 DOI: 10.1111/j.1749-6632.1990.tb42274.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Accelerated atherosclerosis occurs in patients with type III hyperlipoproteinemia and familial hypercholesterolemia. These genetic disorders focus attention on specific types of lipoproteins as being responsible for the development of accelerated coronary artery heart disease. The accumulation of chylomicron remnants of intestinal origin and of VLDL remnants or IDL of hepatic origin observed in type III hyperlipoproteinemia appears to correlate with coronary disease. The presence of defective forms of apo E prevents normal receptor-mediated catabolism of these lipoproteins. Patients with familial hypercholesterolemia have an elevation of plasma LDL (and to a lesser extent an increase in VLDL remnants and IDL) secondary to defective LDL receptors that impair normal catabolism. Familial defective apo B100 is secondary to an abnormality of apo B100 that prevents the normal interaction of LDL with the LDL receptor and increases plasma LDL. However, it has not yet been established that familial defective apo B100 predisposes affected individuals to accelerated atherosclerosis. Animals fed diets high in saturated fat and cholesterol have an accumulation of beta-VLDL, IDL, and LDL that resembles the changes in lipoproteins observed in patients with these genetic disorders. Macrophages (which are presumably derived from circulating monocytes) have emerged as a likely key component in atherogenesis because they appear to be progenitors of foam cells in arterial lesions. Macrophages in the arterial wall express receptors that recognize chylomicron remnants and VLDL remnants (beta-VLDL) and chemically modified LDL. Thus, in the presence of these specific lipoproteins, macrophages are converted to cells that resemble foam cells. The precise stimulus that causes monocyte-derived macrophages to enter specific regions of the arterial wall remains to be determined.
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Affiliation(s)
- K H Weisgraber
- Gladstone Foundation Laboratories for Cardiovascular Disease, Department of Pathology, University of California, San Francisco 94140-0608
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74
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Steinmetz A, Assefbarkhi N, Eltze C, Ehlenz K, Funke H, Pies A, Assmann G, Kaffarnik H. Normolipemic dysbetalipoproteinemia and hyperlipoproteinemia type III in subjects homozygous for a rare genetic apolipoprotein E variant (apoE1). J Lipid Res 1990. [DOI: 10.1016/s0022-2275(20)42740-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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75
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Apolipoprotein E2-Dunedin (228 Arg replaced by Cys): an apolipoprotein E2 variant with normal receptor-binding activity. J Lipid Res 1990. [DOI: 10.1016/s0022-2275(20)43175-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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76
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Abstract
The number of discrete disorders of lipid transport is growing. Concomitantly, the classification of the disorders is changing, from one based on altered concentrations of lipoproteins, to one based on current understanding of the genetics of the disorders and of lipoprotein biochemistry and physiology. Many disorders are now traceable to deficiencies of essential proteins such as apolipoproteins, enzymes, lipid transfer proteins and cellular receptors.
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Affiliation(s)
- G Schonfeld
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110
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Smit M, de Knijff P, van der Kooij-Meijs E, Groenendijk C, van den Maagdenberg AM, Gevers Leuven JA, Stalenhoef AF, Stuyt PM, Frants RR, Havekes LM. Genetic heterogeneity in familial dysbetalipoproteinemia. The E2(lys146—-gln) variant results in a dominant mode of inheritance. J Lipid Res 1990. [DOI: 10.1016/s0022-2275(20)42759-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Apolipoprotein E3-Leiden contains a seven-amino acid insertion that is a tandem repeat of residues 121–127. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(19)30067-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Chappell DA. High receptor binding affinity of lipoproteins in atypical dysbetalipoproteinemia (type III hyperlipoproteinemia). J Clin Invest 1989; 84:1906-15. [PMID: 2556448 PMCID: PMC304071 DOI: 10.1172/jci114378] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Familial dysbetalipoproteinemia (or type III hyperlipoproteinemia) is characterized by the presence of abnormal, cholesteryl ester-rich beta-very low density lipoproteins (beta-VLDL) in the plasma. Subjects with typical dysbetalipoproteinemia are homozygous for an amino acid substitution in apolipoprotein (apo-) E at residue 158 and have defective apo-E-mediated binding of both pre-beta-VLDL and beta-VLDL to apo-B,E(LDL) (or LDL) receptors (1988. Chappell, D.A., J. Clin. Invest. 82:628-639). To understand the effect of substitutions in apo-E at sites other than residue 158, nine dysbetalipoproteinemic (dys-beta) subjects who were either homozygous or heterozygous for substitutions in apo-E at atypical sites were studied. These substitutions occurred at residue 142 (n = 6), 145 (n = 2), or 146 (n = 1) and are known to cause less defective binding than does the 158 substitution. The chemical composition and electrophoretic mobility of pre-beta-VLDL and beta-VLDL from atypical and typical dys-beta subjects were indistinguishable. However, lipoproteins from atypical and typical dys-beta subjects differed in their affinity for the apo-B,E(LDL) receptor on cultured human fibroblasts. The pre-beta-VLDL and beta-VLDL from atypical dys-beta subjects had 640- or 17-fold higher affinity, respectively, than did corresponding lipoproteins from typical dys-beta subjects. The higher binding affinity of lipoproteins from atypical dys-beta subjects was associated with a higher ratio of apo-E to total apo-C. Since higher binding affinity should cause more rapid receptor-mediated clearance of beta-VLDL in atypical than in typical dys-beta subjects in vivo, the mechanism of beta-VLDL accumulation may differ in these two groups.
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MESH Headings
- Adolescent
- Adult
- Aged
- Animals
- Apolipoproteins B/blood
- Apolipoproteins E/blood
- Apolipoproteins E/genetics
- Binding, Competitive
- Cells, Cultured
- Child
- Cholesterol, Dietary/administration & dosage
- Dogs
- Electrophoresis, Polyacrylamide Gel
- Female
- Fibroblasts/metabolism
- Humans
- Hyperlipoproteinemia Type III/blood
- Hyperlipoproteinemia Type III/genetics
- Lipoproteins, LDL/metabolism
- Lipoproteins, VLDL/blood
- Lipoproteins, VLDL/isolation & purification
- Male
- Middle Aged
- Mutation
- Rabbits
- Receptors, Cell Surface/metabolism
- Receptors, LDL/metabolism
- Receptors, Lipoprotein
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Affiliation(s)
- D A Chappell
- Gladstone Foundation Laboratories for Cardiovascular Disease, Department of Internal Medicine, University of California, San Francisco 94140
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