リポ蛋白X
WordNet
- the 24th letter of the Roman alphabet (同)x, ex
- a conjugated protein having a lipid component; the principal means for transporting lipids in the blood
PrepTutorEJDIC
- Christ / Christian
- x-axis
Wikipedia preview
出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2015/09/29 02:54:52」(JST)
[Wiki en表示]
Lipoprotein-X (Lp-X) is an abnormal low density lipoprotein found in cholestasis.
Structure
Lipoprotein-X is a lamellar particle of 30 to 70 nm in diameter as revealed by electron microscopy. It is characterized by its high content of phospholipids (66% by weight) and unesterified cholesterol (22%), and its low content of protein (6%), cholesterol esters (3%), and triglycerides (3%). The protein component is dominated by albumin, located in the core, and by apolipoprotein C, located on the surface of the particle. Using zonal ultracentrifugation, lipoprotein-X can be divided into three distinct populations: Lp-X1, Lp-X2, and Lp-X3, differing in density and apolipoprotein composition.
Pathogenesis
The pathogenesis of lipoprotein-X in cholestasis is not totally resolved. Normally, the liver excretes lipoprotein complexes into the bile showing phospholipid and unesterified cholesterol concentrations similar to Lipoprotein-X. The in vitro incubation of these bile lipoproteins with serum or albumin leads to the appearance of Lp-X–like particles. These findings suggest that the reflux of bile into the plasma compartment causes the formation of lipoprotein-X in cholestasis as a result of a physicochemical, nonmetabolic process. On the other hand, lipoprotein-X particles found in familial LCAT deficiency are identical to those in cholestasis regarding ultrastructure and biochemical composition. It has been supposed that reduced LCAT activities, common in patients with hepatocellular disease, cause, alone or in combination with other factors, the formation of Lipoprotein-X in cholestasis. Lipoprotein-X is mainly removed by the reticuloendothelial system of the liver and the spleen, as shown by studies using radioactively labeled lipoprotein-X in rats. Other organs, such as the kidney, also actively clear Lipoprotein-X from the plasma.
Literature
- Seidel D, Alaupovic P, Furman RH (July 1969). "A lipoprotein characterizing obstructive jaundice. I. Method for quantitative separation and identification of lipoproteins in jaundiced subjects". J. Clin. Invest. 48 (7): 1211–23. doi:10.1172/JCI106085. PMC 322342. PMID 4978447.
- Seidel D, Alaupovic P, Furman RH, McConathy WJ (December 1970). "A lipoprotein characterizing obstructive jaundice. II. Isolation and partial characterization of the protein moieties of low density lipoproteins". J. Clin. Invest. 49 (12): 2396–407. doi:10.1172/JCI10645910.1172/JCI106459. PMC 322741. PMID 5480863.
- Sörös P, Böttcher J, Maschek H, Selberg O, Müller MJ (November 1998). "Lipoprotein-X in patients with cirrhosis: its relationship to cholestasis and hypercholesterolemia". Hepatology 28 (5): 1199–205. doi:10.1002/hep.510280506. PMID 9794902.
UpToDate Contents
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English Journal
- A kindred with fish eye disease, corneal opacities, marked high-density lipoprotein deficiency, and statin therapy.
- Dimick SM1, Sallee B2, Asztalos BF3, Pritchard PH4, Frohlich J4, Schaefer EJ3.Author information 1Central Oklahoma Early Detection Center, Lipidology and Cardiometabolic Clinic, 1227 East 9th Street, Edmond, OK 73034, USA; The University of Oklahoma College of Medicine, 941 Stanton L. Young Boulevard, Oklahoma City, Oklahoma 73104, USA. Electronic address: susandimickmd@hotmail.com.2Central Oklahoma Early Detection Center, Lipidology and Cardiometabolic Clinic, 1227 East 9th Street, Edmond, OK 73034, USA; The University of Oklahoma College of Medicine, 941 Stanton L. Young Boulevard, Oklahoma City, Oklahoma 73104, USA. Electronic address: brigitte-sallee@ouhsc.edu.3Boston Heart Diagnostics, Framingham, MA, USA; Lipid Metabolism Laboratory, Human Nutrition Research Center on Aging at Tufts University and Tufts University School of Medicine, Boston, MA, USA.4Atherosclerosis Specialty Laboratory, Department of Pathology and Laboratory Medicine, St. Paul's Hospital, University of British Columbia, Vancouver, Canada.AbstractA kindred affected with fish eye disease (FED) from Oklahoma is reported. Two probands with corneal opacification had mean levels of high-density lipoprotein (HDL) cholesterol (C), apolipoprotein (apo) A-I, and apoA-I in very large alpha-1 HDL particles that were 9%, 17%, and 5% of normal, whereas their parents and 1 sibling had values that were 61%, 77%, and 72% of normal. The probands had no detectable lipoprotein-X, and had mean low-density lipoprotein cholesterol (LDL-C) and triglyceride levels that were elevated. Their mean lecithin cholesterol acyltransferase (LCAT) activities, cholesterol esterification rates, and free cholesterol levels were 8%, 42%, and 258% of normal, whereas their parents and 1 sibling had values that were 55%, 49%, and 114% of normal. The defect was due to 1 common variant in the LCAT gene in exon 1: c101t causing a proline34leucine substitution and a novel mutation c1177t causing a threonine37methionine substitution, with the former variant being found in the father and 1 sibling, and the latter mutation being found in the mother, and both mutations being present in the 2 probands. FED is distinguished from familial LCAT deficiency (FLD) by the lack of anemia, splenomegaly, and renal insufficiency as well as normal or increased LDL-C. Both FLD and FED cases have marked HDL deficiency and corneal opacification, and FED cases may have premature coronary heart disease in contrast to FLD cases. Therapy, using presently available agents, in FED should be to optimize LDL-C levels, and 1 proband responded well to statin therapy. The investigational use of human recombinant LCAT as an enzyme source is ongoing.
- Journal of clinical lipidology.J Clin Lipidol.2014 Mar-Apr;8(2):223-30. doi: 10.1016/j.jacl.2013.11.005. Epub 2013 Dec 11.
- A kindred affected with fish eye disease (FED) from Oklahoma is reported. Two probands with corneal opacification had mean levels of high-density lipoprotein (HDL) cholesterol (C), apolipoprotein (apo) A-I, and apoA-I in very large alpha-1 HDL particles that were 9%, 17%, and 5% of normal, whereas t
- PMID 24636183
- Lipoprotein X: clinical implications.
- Crook MA.
- Annals of clinical biochemistry.Ann Clin Biochem.2013 Mar;50(Pt 2):93-4. doi: 10.1177/0004563213478804.
- PMID 23512171
- Lipoprotein X in a patient with cholestasis and hypertriglyceridaemia.
- Stepien KM1, Divyateja H, Ahmed F, Prinsloo P, Gupta P.Author information 1Nottingham University Hospitals Trust, Hucknall Road, Nottingham NG5 1PB, UK. kstepien@doctors.org.ukAbstractHypertriglyceridaemia is an established cause of acute pancreatitis and responds to insulin therapy in addition to lipid lowering medication. We report a case of severe hypertriglycaeridemia of 149 mmol/L in a 36-year-old man with type 2 diabetes who presented to the surgical ward with abdominal pain due to pancreatitis and developed acute cholestasis, jaundice and eruptive xanthomata. His triglycerides improved to 3.8 mmol/L with sliding scale insulin within two weeks of in-hospital stay. However, his total cholesterol remained raised at 23.7 mmol/L. The lipoprotein electrophoresis confirmed the presence of lipoprotein X associated with bile obstruction, which contributed to an increase in total cholesterol. The total cholesterol normalized on improvement of his cholestasis.
- Annals of clinical biochemistry.Ann Clin Biochem.2013 Mar;50(Pt 2):173-5. doi: 10.1258/acb.2012.012148. Epub 2013 Feb 21.
- Hypertriglyceridaemia is an established cause of acute pancreatitis and responds to insulin therapy in addition to lipid lowering medication. We report a case of severe hypertriglycaeridemia of 149 mmol/L in a 36-year-old man with type 2 diabetes who presented to the surgical ward with abdominal pai
- PMID 23431481
Japanese Journal
- A Case of Type 2 Diabetes and Metastatic Liver Cancer Exhibiting Hypercholesterolemia with Abnormal Lipoproteins
- Kanzaki Motoko,Wada Jun,Nakatsuka Atsuko,Teshigawara Sanae,Murakami Kazutoshi,Inoue Kentaro,Terami Takahiro,Katayama Akihiro,Nasu Junichiro,Yamamoto Kazuhide,Makino Hirofumi
- Internal Medicine 51(6), 619-623, 2012
- … High-performance liquid chromatography demonstrated the presence of lipoprotein-X and lipoprotein-Y and sigmoid colon cancer and multiple liver metastases were found by colonoscopy and computed tomography. …
- NAID 130002061924
- Development of Formulas for Estimation of Cholesterol Levels in Major Serum Lipoproteins Separated by Agarose Gel Electrophoresis
- Vanavanan Somlak,Chaloeysup Sirirat,Kotani Kazuhiko,Srisawasdi Pornpen
- Journal of Electrophoresis 55(1), 23-29, 2011
- … Background/aim: Electrophoresis is useful for examining the lipoprotein fraction patterns. … A simultaneous and cost-effective addition of cholesterol levels in each lipoprotein fraction to the lipoprotein patterns can more assist clinical decision-making. … The formulas for estimation of relative cholesterol (%) of individual lipoprotein fractions were developed using linear regression models. …
- NAID 130000792159
- 異常リポ蛋白Lp-Xに対するLDL-Cホモジニアス法の反応特異性の研究
- 松嶋 和美,杉内 博幸,西村 仁志,池田 勝義,安東 由喜雄
- 医学検査 : 日本臨床衛生検査技師会誌 = The Japanese journal of medical technology 59(1), 38-43, 2010-01-25
- NAID 10026333990
Related Links
- Lipoprotein-X. From Wikipedia, the free encyclopedia. Jump to: navigation, search. Lipoprotein-X (Lp-X) is an abnormal low density lipoprotein found in cholestasis. [edit] Structure. Lipoprotein-X is a lamellar particle of 30 to 70 nm in diameter ...
- Lipoprotein-X is an abnormal lipoprotein that appears in the sera of patients with obstructive jaundice, and thus is a sensitive indicator of cholestasis. In patients with familial plasma lecithin, Cholesterol acyltransferase (LCAT) deficiency, there ...
Related Pictures
★リンクテーブル★
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- 英
- lipoprotein X, LpX, lipoprotein-X
- 関
- リポ蛋白質
[show details]
- 胆汁うっ滞をきたす病態において血漿中に増加が見られる異常リポ蛋白。
参考
- 1. lipoprotein-X electrophoresis
- http://www.nature.com/ki/journal/v60/n2/fig_tab/4492450f1.html
- 2. Lipoprotein-X and LCAT Deficiency Thomas Dayspring MD, FACP
- http://www.lipidcenter.com/pdf/LipoproteinX.pdf
- http://en.wikipedia.org/wiki/Lipoprotein-X
- Narayanan S.AbstractLipoprotein-X is an abnormal lipoprotein that appears in the sera of patients with obstructive jaundice, and thus is a sensitive indicator of cholestasis. In patients with familial plasma lecithin, Cholesterol acyltransferase (LCAT) deficiency, there is an inverse relationship between plasma Lp-X levels and LCAT activity. Ultracentrifugation procedures utilized for isolation of Lp-X have shown that it is associated with the low density lipoprotein fraction. Lp-X can be visualized by electrophoresis on either Agar or Agarose. The purity of Lp-X preparations has been documented by immunochemical procedures. The availability of highly purified antisera to Lp-X has served as a basis of one of the assay procedures for this lipoprotein. It's chemical composition has been established. Phospholipids and unesterified cholesterol constitute the bulk of the Lp-X molecule. Electron microscopic studies have demonstrated that Lp-X is a spherical particle which has strong aggregating properties. Membrane bound enzymes have been shown to aggregate with Lp-X. The fact that bile lipoprotein can be converted to Lp-X by the addition of albumin and that Lp-X can be converted to bile lipoprotein by the addition of bile salts offers a possible explanation for the origins of Lp-X. Phospholipases of plasma might play a role in the catabolism of Lp-X. The value and limitations of Lp-X determinations will also be addressed in this review.
- CRC critical reviews in clinical laboratory sciences.CRC Crit Rev Clin Lab Sci.1979 Aug;11(1):31-51.
- Lipoprotein-X is an abnormal lipoprotein that appears in the sera of patients with obstructive jaundice, and thus is a sensitive indicator of cholestasis. In patients with familial plasma lecithin, Cholesterol acyltransferase (LCAT) deficiency, there is an inverse relationship between plasma Lp-X le
- PMID 389551
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キサントシン, xanthosine
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リポ蛋白 lipoprotein
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リポ蛋白 lipoprotein