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FAMILIAL CHYLOMICRONEMIA SYNDROME. A SIXTY YEAR FOLLOW-UP IN TWO SIBLINGS AND THEIR KINDREDS. NOSOLOGICAL AND CLINICAL CONSIDERATIONS. J Clin Lipidol 2022; 16:591-595. [DOI: 10.1016/j.jacl.2022.07.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/24/2022] [Accepted: 07/26/2022] [Indexed: 11/17/2022]
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Tabuchi M, Seo M, Inoue T, Ikeda T, Kogure A, Inoue I, Katayama S, Matsunaga T, Hara A, Komoda T. Geometrical Separation Method for Lipoproteins Using Bioformulated-Fiber Matrix Electrophoresis: Size of High-Density Lipoprotein Does Not Reflect Its Density. Anal Chem 2010; 83:1131-6. [DOI: 10.1021/ac102402c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mari Tabuchi
- Department of Chemistry, Faculty of Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan
- Research Information Center for Extremophile, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan
| | - Makoto Seo
- Department of Biochemistry, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Moroyama, Iruma-gun, Saitama 350-0495, Japan
| | - Takayuki Inoue
- Department of Chemistry, Faculty of Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan
| | - Takeshi Ikeda
- Department of Chemistry, Faculty of Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan
| | - Akinori Kogure
- Surface Analysis Division, Shimadzu Analytical & Measuring Center, Inc. 380-1, Horiyamashita, Hadano-city, Kanagawa, 259-1304, Japan
| | - Ikuo Inoue
- Department of Endocrinology and Diabetes, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Moroyama, Iruma-gun, Saitama 350-0495, Japan
| | - Shigehiro Katayama
- Department of Endocrinology and Diabetes, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Moroyama, Iruma-gun, Saitama 350-0495, Japan
| | - Toshiyuki Matsunaga
- Laboratory of Biochemistry, Gifu Pharmaceutical University, 5-6-1 Mitahora-higashi, Gifu 502-8585, Japan
| | - Akira Hara
- Laboratory of Biochemistry, Gifu Pharmaceutical University, 5-6-1 Mitahora-higashi, Gifu 502-8585, Japan
| | - Tsugikazu Komoda
- Department of Biochemistry, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Moroyama, Iruma-gun, Saitama 350-0495, Japan
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Ikeda T, Seo M, Inoue I, Katayama S, Matsunaga T, Hara A, Komoda T, Tabuchi M. Direct and simple fluorescence detection method for oxidized lipoproteins. Anal Chem 2010; 82:1128-32. [PMID: 20043691 DOI: 10.1021/ac902018a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The quantification of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) is currently one of the most important clinical measurements for characterizing metabolic syndrome. However, recent studies have revealed additional factors that may be more strongly associated with the coronary heart disease than simple measurement of LDL or HDL levels, such as small dense (sd) LDL particles and oxidized LDL or HDL particles. Although several methods using enzyme-antibody detection systems or fluorescent probes have been devised to characterize these factors, such methods are expensive to implement for clinical measurements. Here, we present a straightforward analytical method for direct quantitation of oxidized lipoproteins by fluorescence spectrometry, with excitation in the UV (365 +/- 10 nm) or visible (470 +/- 10 nm) range and emission detected at 450 +/- 30 nm or 535 +/- 15 nm. This method can be readily applied for clinical measurement in patients with dyslipidemia using only 1 microL of 1 mg/mL of lipoprotein and without the need for any expensive detection antibodies. Using this new technique, biological samples from patients with dyslipidemia showed higher fluorescence intensities than samples from normal subjects when detecting oxidized LDL and light HDL (d = 1.063-1.125 g/mL), whereas samples from patients with dyslipidemia showed lower fluorescence intensities than samples from normal subjects when measuring oxidized heavy HDL (d = 1.125-1.210 g/mL) levels.
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Affiliation(s)
- Takeshi Ikeda
- Department of Chemistry, Graduate School of Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan
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Fisher RM, Miles JM, Kottke BA, Frayn KN, Coppack SW. Very-low-density lipoprotein subfraction composition and metabolism by adipose tissue. Metabolism 1997; 46:605-10. [PMID: 9186293 DOI: 10.1016/s0026-0495(97)90001-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Lipoprotein lipase (LPL) plays a pivotal role in very-low-density lipoprotein (VLDL) metabolism. Within the circulation, the VLDL population is heterogeneous with respect to both size and composition. Several studies have investigated the action of LPL in vitro on different VLDL subfractions, but little is known of the action of LPL in vivo. To investigate this, arterial and adipose tissue venous plasma samples were obtained from 16 normal male healthy volunteers (aged 24.4 +/- 1.8 years; body mass index, 23.5 +/- 0.7 kg.m-2) following an overnight fast. VLDL subfractions were isolated (VLDL1 of Sf 60 to 400 and VLDL2 of Sf 20 to 60) and characterized in terms of triacylglycarol (TAG) and apolipoprotein (apo) B, E, CI, CII, and CIII content. The apolipoprotein content of VLDL1 differed from that of VLDL2: the VLDL2 fraction contained significantly more apo B (0.018 +/- 0.004 v 0.011 +/- 0.003 mumol.L-1, p = .001) but the ratios of TAG:apo B and apo CI:B, and CII:B, and CIII:B were significantly higher in VLDL1 (48,200 +/- 7,980 v 13,860 +/- 2,420, 22.7 +/- 5.5 v 12.5 +/- 2.2, 45.0 +/- 6.3 v 14.9 +/- 2.0, and 0.434 +/- 0.077 v 0.357 +/- 0.054, respectively, molar ratios, all P < .05). The venous blood draining an adipose tissue depot contained less VLDL1-TAG than arterial blood (328 +/- 68 v 381 +/- 83 mumol.L-1, respectively, P < .01), whereas VLDL2-TAG exhibited an opposite tendency (199 +/- 46 v 172 +/- 31 mumol.L-1, NS). Concentrations of VLDL1-apo B, -apo CII, and -apo CIII were significantly less in adipose tissue venous blood compared with arterial blood (0.011 +/- 0.004 v 0.013 +/- 0.004, 0.38 +/- 0.08 v 0.43 +/- 0.10, and 1.33 +/- 0.35 v 1.58 +/- 0.38 mumol.L-1, respectively, all P < .05). These studies demonstrated novel differences in VLDL1 and VLDL2 in terms of composition and metabolism by human adipose tissue LPL in vivo.
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Affiliation(s)
- R M Fisher
- Endocrine Research Unit, Mayo Clinic, Rochester, MN, USA
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Fisher RM, Coppack SW, Humphreys SM, Gibbons GF, Frayn KN. Human triacylglycerol-rich lipoprotein subfractions as substrates for lipoprotein lipase. Clin Chim Acta 1995; 236:7-17. [PMID: 7664467 DOI: 10.1016/0009-8981(95)06032-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In order to test the hypothesis that lipoprotein lipase (LPL) acts preferentially on larger lipoprotein particles, we determined the susceptibility of triacylglycerol-rich lipoprotein (TRL) subfractions to hydrolysis by LPL in vitro. Chylomicrons (Sf > 400), very low density lipoproteins (VLDL)1 (Sf 60-400) and VLDL2 (Sf 20-60) were isolated from six subjects with a range of plasma-triacylglycerol (TAG) concentrations following an overnight fast and for up to 6 h after the consumption of a mixed meal (41% fat). The percent of TRL-TAG hydrolysed by LPL in subfractions isolated following overnight fast was VLDL1 > VLDL2 (46.8 +/- 10.2 vs. 25.9 +/- 7.4%, P = 0.006) and 3 h after the meal it was chylomicrons > VLDL1 > VLDL2 (81.0 +/- 12.6 vs. 52.8 +/- 10.2 vs. 27.7 +/- 6.2%, chylomicrons vs. VLDL1 and VLDL1 vs. VLDL2, both P < or = 0.005). The percent of VLDL1-TAG hydrolysed increased both within and between subjects as VLDL1-TAG concentrations increased. This relationship could be explained by the positive correlation observed between VLDL1-TAG and VLDL1-TAG:apolipoprotein B. In conclusion, increasing the size and TAG content of a lipoprotein particle increases its susceptibility to hydrolysis by LPL.
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Affiliation(s)
- R M Fisher
- Oxford Lipid Metabolism Group, Sheikh Rashid Laboratory, Radcliffe Infirmary, UK
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Campos H, Dreon DM, Krauss RM. Associations of hepatic and lipoprotein lipase activities with changes in dietary composition and low density lipoprotein subclasses. J Lipid Res 1995. [DOI: 10.1016/s0022-2275(20)39880-1] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Williams PT, Krauss RM, Stefanick ML, Vranizan KM, Wood PD. Effects of low-fat diet, calorie restriction, and running on lipoprotein subfraction concentrations in moderately overweight men. Metabolism 1994; 43:655-63. [PMID: 8177056 PMCID: PMC2828467 DOI: 10.1016/0026-0495(94)90210-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We studied the effects of exercise (primarily running), calorie restriction (dieting), and a low-fat, high-carbohydrate diet on changes in lipoprotein subfractions in moderately overweight men in a randomized controlled clinical trial. After 1 year, complete data were obtained for 39 men assigned to lose weight through dieting without exercise, 37 men assigned to lose weight through dieting with exercise (primarily running), and 40 nondieting sedentary controls. We instructed both diet groups to consume no more than 30% total fat, 10% saturated fat, and 300 mg/d of cholesterol, and at least 55% carbohydrates, and the controls were instructed to maintain their usual food choices. Analytic ultracentrifugation was used to measure changes in plasma lipoprotein mass concentrations. In addition, the absorbance of protein-stained polyacrylamide gradient gels was used as an index of concentrations for five high-density lipoprotein (HDL) subclasses that have been identified by their particle sizes, ie, HDL3c (7.2 to 7.8 nm), HDL3b (7.8 to 8.2 nm), HDL3a (8.2 to 8.8 nm), HDL2a (8.8 to 9.7 nm), and HDL2b (9.7 to 12 nm). Relative to controls, weight decreased significantly in men who dieted with exercise (net difference +/- SE, -3.3 +/- 0.4 kg/m2) and in men who dieted without exercise (-2.0 +/- 0.4 kg/m2). Dieting with exercise significantly decreased very-low-density lipoprotein (VLDL)-mass concentrations and significantly increased plasma HDL2-mass, HDL3a, HDL2a, and HDL2b relative to both control and dieting without exercise. There were no significant changes in lipoprotein mass and HDL protein for dieters who did not run.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- P T Williams
- Stanford Center for Research in Disease Prevention, Stanford University School of Medicine, CA
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Manzato E, Zambon S, Zambon A, Cortella A, Sartore G, Crepaldi G. Levels and physicochemical properties of lipoprotein subclasses in moderate hypertriglyceridemia. Clin Chim Acta 1993; 219:57-65. [PMID: 8306464 DOI: 10.1016/0009-8981(93)90197-c] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Moderate hypertriglyceridemia is associated with several abnormalities of the plasma lipoprotein particles and it may be a risk factor for atherosclerotic vascular diseases. Plasma lipid, lipoprotein and apolipoprotein levels, as well as lipoprotein composition and physical properties, were examined by ultracentrifugation in a zonal rotor and by gradient gel electrophoresis in 14 patients with moderate hypertriglyceridemia (plasma triglycerides 4.00 +/- 0.32 mmol/l, mean +/- S.D.) and in 14 control subjects. Based on zonal ultracentrifugation hypertriglyceridemic patients have higher levels of cholesterol in all VLDL subclasses (Sf > 200, 100-200, 60-100 and 20-60), in IDL and in small and dense LDL. Both HDL2 and HDL3 cholesterol levels are reduced. The LDL flotation rate is inversely related to plasma triglyceride levels, thus indicating that the higher the plasma triglycerides the smaller and/or denser the LDL are. The triglyceride percent content of LDL2 and HDL3 is increased, while that of esterified cholesterol is reduced in hypertriglyceridemic patients. Gradient gel electrophoresis shows that the LDL peak size is lower (25.2 +/- 0.5 nm, mean +/- S.D.) in hypertriglyceridemic than in control subjects (27.1 +/- 0.4 nm; P < 0.0001). Considering both hypertriglyceridemic and control subjects the LDL peak effluent volume from the zonal rotor (which reflects the LDL flotation rate) is inversely related to the LDL peak size determined by gradient gel electrophoresis (r = -0.71; P = 0.0006) and the plasma triglyceride levels are related to LDL peak effluent volume (r = 0.74; P = 0.0002) and to LDL peak size (r = -0.95; P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- E Manzato
- Department of Internal Medicine, University of Padua, Italy
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Zambon S, Zambon A, Stabellini N, Tarroni G, Gilli P, Crepaldi G, Manzato E. Lipoprotein abnormalities in hypertriglyceridaemic patients on long-term haemodialysis. J Intern Med 1993; 234:217-21. [PMID: 8340745 DOI: 10.1111/j.1365-2796.1993.tb00733.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVES To analyse by ultracentrifugation in a zonal rotor the plasma lipoproteins in hypertriglyceridaemic patients on long-term haemodialysis. DESIGN Case-control study. SETTING Tertiary referred care centre. SUBJECTS Ten consecutive hypertriglyceridaemic patients on haemodialysis and 12 consecutive healthy controls. MAIN OUTCOME MEASURES Plasma lipid and lipoprotein cholesterol concentrations, lipoprotein physical properties and compositions, apolipoprotein concentrations. RESULTS Hypertriglyceridaemia in patients undergoing haemodialysis is characterized by an increased amount of small and slow floating very-low density lipoproteins (VLDL), higher concentrations of intermediate density lipoproteins (IDL) and small and dense low-density lipoprotein (LDL) particles; reduced levels of high-density lipoproteins (HDL), in particular of HDL2. The lipoprotein composition of such patients indicates reduced cholesterol ester and increased triglyceride content. Compared to controls, they have lower levels of plasma apolipoprotein A-I and A-II and higher B, C-II, C-III and E values. CONCLUSIONS The lipoprotein abnormalities observed in hypertriglyceridaemic patients undergoing haemodialysis have recently been associated with an increased incidence of vascular complications and may in part explain the high incidence of vascular disease reported in these subjects.
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Affiliation(s)
- S Zambon
- Department of Internal Medicine, University of Padova, Italy
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Manzato E, Zambon A, Zambon S, Nosadini R, Doria A, Marin R, Crepaldi G. Lipoprotein compositional abnormalities in type 1 (insulin-dependent) diabetic patients. Acta Diabetol 1993; 30:11-6. [PMID: 8329725 DOI: 10.1007/bf00572867] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Patients with type 1 (insulin-dependent) diabetes mellitus in good metabolic control usually have normal plasma lipid levels yet they have an increased incidence of vascular complications. Abnormalities in the distribution and composition of lipoprotein subfractions might in part be responsible for the macroangiopathy seen in type 1 diabetes mellitus. The plasma lipids, lipoproteins and apolipoproteins were studied in 9 type 1 diabetic patients during conventional insulin therapy and in 14 healthy controls. Plasma lipoproteins were analysed by ultracentrifugation in a zonal rotor to evaluate their concentrations and flotation properties and for compositional analysis. In diabetic patients the mean glycosylated haemoglobin (HbA1c) was 9.44 +/- 1.02% and the plasma lipid concentrations were not significantly different from healthy controls. The very low density lipoprotein (VLDL) subclass cholesterol concentrations were no different in diabetic patients and control subjects, but the VLDL cholesterol/triglyceride ratio was significantly lower in diabetic patients than in control subjects (0.43 +/- 0.05 vs 0.85 +/- 0.14; p < 0.05). The flotation rate LDL2, the major component of low density lipoprotein (LDL) was lower in the diabetic patients compared with the control subjects. The cholesterol concentrations of intermediate density lipoprotein and LDL3, the minor component of LDL, were significantly higher (0.17 +/- 0.03 and 0.83 +/- 0.14 mmol/l respectively) in diabetic patients than in control subjects (0.05 +/- 0.02 and 0.24 +/- 0.08 mmol/l). The flotation properties and cholesterol concentrations of the high density lipoprotein (HDL) subclass, and the protein-lipid composition of LDL2, HDL2 and HDL3, were no different in diabetic patients and control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- E Manzato
- Department of Internal Medicine, University of Padua, Italy
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Beil FU, Fojo SS, Brewer HB, Greten H, Beisiegel U. Apolipoprotein C-II deficiency syndrome due to apo C-IIHamburg: clinical and biochemical features and HphI restriction enzyme polymorphism. Eur J Clin Invest 1992; 22:88-95. [PMID: 1349286 DOI: 10.1111/j.1365-2362.1992.tb01941.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have characterized the clinical and biochemical features of three siblings of a kindred with severe hypertriglyceridaemia due to apolipoprotein C-II (apo C-II) deficiency caused by the mutation described as apo C-IIHamburg. The clinical syndrome is characterized by recurrent pancreatitis in two of three affected individuals, with discrete hepatosplenomegaly in all three patients and cholelithiasis in one. Eruptive xanthomas and lipemia retinalis were absent. Plasma lipoproteins were characterized by fasting chylomicronaemia, reduced low density lipoproteins (LDL) and low high density lipoproteins (HDL). The marked hypertriglyceridaemia could be corrected promptly by infusion of normal plasma. Apolipoprotein C-II (apo C-II) levels in homozygotes were very low (0.01 mg dl-1), and mean apo C-II levels in heterozygotes were lower (2.08 +/- 0.11 mg dl-1) than in normal family members (3.38 +/- 0.75 mg dl-1). Lipoprotein lipase and hepatic triglyceride lipase activities in post-heparin plasma were normal. Zonal ultracentrifugation revealed a marked increase in triglyceride-rich lipoproteins and reduced LDL and HDL. LDL consisted of two fractions with higher hydrated density of the main fraction compared with normals with a trend to normalization on a fat-free diet. The molecular defect in the apo C-II Hamburg gene has been previously identified as a donor splice site mutation in the second intron. This leads to abnormal splicing of the apo C-II Hamburg mRNA and apo C-II deficiency in plasma. The mutation causes the loss of an HphI restriction enzyme site present in the normal apo C-II gene.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- F U Beil
- Universitätsklinik Eppendorf, Hamburg, Germany
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Swinkels DW, Demacker PN, Hendriks JC, van 't Laar A. Low density lipoprotein subfractions and relationship to other risk factors for coronary artery disease in healthy individuals. ARTERIOSCLEROSIS (DALLAS, TEX.) 1989; 9:604-13. [PMID: 2783074 DOI: 10.1161/01.atv.9.5.604] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
By a recently developed sensitive density gradient ultracentrifugation method, the distribution of low density lipoprotein (LDL) subfractions was studied in the serum of healthy blood donors (20 to 62 years old). For each subject, we observed a specific LDL subfraction distribution characterized by the relative contribution of the three major LDL subfractions, LDL-1 (1.020 to 1.028 g/ml), LDL-2 (1.027 to 1.034 g/ml), and LDL-3 (1.033 to 1.039 g/ml), to total LDL. Statistical analysis was performed by using the LDL density variable defined as: (% of LDL-1) x 1.024 + (% of LDL-2) x 1.0305 + (% of LDL-3) x 1.036 as a continuous variable. Controlling for age, smoking habits, relative body weight and, when appropriate, for gender, it appeared that: 1) dense LDL subfraction patterns characterized by a predominant LDL-3 subfraction and a decreased LDL particle size were more likely to be found among men than among women, 2) with increasing density of LDL, the levels of serum triglycerides increased, whereas the concentration of HDL cholesterol and the ratio of LDL cholesterol to LDL apolipoprotein (apo) B decreased, and 3) the best model with significant contribution in the prediction of the LDL subfraction distribution was the three-variable model: total cholesterol, serum triglycerides, and LDL apo B (R2 = 0.40), whereas the best two-variable model consisted of serum triglycerides and high density lipoprotein cholesterol (R2 = 0.37). These data are consistent with results from a study described previously in which a different approach based on LDL subfraction quantification by gradient gel electrophoresis of whole plasma was used.
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Affiliation(s)
- D W Swinkels
- Department of Medicine, University of Nijmegen, The Netherlands
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Swaney JB, Orishimo MW. Effects of heparin-induced lipolytic activity on the structure of rat high-density lipoprotein. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 1002:338-47. [PMID: 2713384 DOI: 10.1016/0005-2760(89)90348-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Following its secretion into the plasma compartment, the high-density lipoprotein (HDL) is presumed to be acted upon by both soluble enzymes, such as lecithin:cholesterol acyltransferase (LCAT), and membrane-associated enzymes, such as lipoprotein lipase and hepatic lipase. Rats were injected intravenously with heparin to release membrane-associated lipolytic activities into the circulation and the collected plasma was incubated overnight at 37 degrees C in the presence or absence of an LCAT inhibitor or an inhibitor of lipoprotein lipase (1 M NaCl). It was observed that lipoprotein lipase accounted for most of the triglyceride hydrolase activity in the heparin-treated plasma, and that the heparin-releasable activities caused an increase in HDL density but no measurable change in particle size when LCAT was inhibited. Heparin treatment caused about a 60% decrease in plasma triacylglycerol during the interval between injection of heparin and blood collection. Although this caused marked compositional changes in the d less than 1.063 g/ml lipoproteins, no changes were observed in the lipid composition or apoprotein distribution in the HDL. Subsequent incubation for 18 h at 37 degrees C produced marked increases in the apoE content of HDL from heparin-treated plasma even when LCAT was inhibited. Time-course studies showed that in the presence of an LCAT inhibitor there was considerable conversion of phosphatidylcholine to lysophosphatidylcholine in heparin-treated plasma, and that this activity was diminished by 1 M NaCl, but that no phospholipolysis was observed in control plasma. By contrast, both heparin-treated and control plasma possessed substantial triglyceride hydrolase activity. The concurrent action of lipases and LCAT was observed to reduce the maximum level of cholesterol esterification which could be achieved in the absence of lipase activity. It is concluded that changes in HDL particle size are mainly attributable to LCAT, but that lipase activities, which are either free in rat plasma or releasable by heparin, play a role in restructuring the phospholipid moiety and altering the protein composition of the HDL, especially with respect to apoE, a potential ligand to cellular receptors.
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Affiliation(s)
- J B Swaney
- Department of Biological Chemistry, Hahnemann University, Philadelphia, PA 19102
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Minnich A, Nordestgaard BG, Zilversmit DB. A novel explanation for the reduced LDL cholesterol in severe hypertriglyceridemia. J Lipid Res 1989. [DOI: 10.1016/s0022-2275(20)38363-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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16
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Gibson JC, Brown WV. Effect of lipoprotein lipase and hepatic triglyceride lipase activity on the distribution of apolipoprotein E among the plasma lipoproteins. Atherosclerosis 1988; 73:45-55. [PMID: 3178931 DOI: 10.1016/0021-9150(88)90162-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The independent roles of human lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) in determining the distribution of apolipoprotein E (apo E) among the plasma lipoproteins has been studied in vitro. In one series of three studies, postheparin plasma (10%) was incubated for 2 h with autologous plasma and the changes in the lipoprotein association of apo E after lipase exposure were determined after lipoprotein fractionation on 4% agarose columns. Specificity for LPL or HTGL was achieved by inhibition with goat anti-human HTGL or with 1 M NaCl, respectively. In another study, LPL and HTGL were partially purified from human postheparin plasma. The independent effects of these enzymes on the lipoprotein association of apo E were then examined after incubation of plasma in the absence or presence of one or both lipases. Data from both types of in vitro study showed that LPL-mediated triglyceride hydrolysis in the absence of HTGL activity was accompanied by a loss of apo E from triglyceride-rich lipoproteins, a gain or no change in the apo E-containing lipoproteins the size of intermediate density lipoproteins (IDL) and inconsistent changes in the apo E mass associated with high density lipoproteins (HDL). HTGL activity, on the other hand, in the absence of LPL, resulted in a redistribution of apo E from lipoproteins the size of IDL and a gain by those of HDL size. These studies thus support previous in vivo studies which pointed toward a specific role for HTGL in the processing of apo E containing IDL.
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Affiliation(s)
- J C Gibson
- Department of Medicine, University of Miami School of Medicine, FL
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