The utilisation of esterified and unesterifled cholesterol derived from chylomicron remnants and high density lipoprotein for bile acid synthesis

1993 ◽  
Vol 21 (4) ◽  
pp. 459S-459S ◽  
Author(s):  
ELENA BRAVO ◽  
ALFREDO CANTAFORA ◽  
TAYFUN GULDUR ◽  
MALCOLM A. MINDHAM ◽  
PETER A. MAYES ◽  
...  
Keyword(s):  
Bile Acid ◽  
High Density Lipoprotein ◽  
Density Lipoprotein ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
High Density ◽  
Chylomicron Remnants

scholarly journals Cholesterol esters selectively delivered in vivo by high-density-lipoprotein subclass LpA-I to rat liver are processed faster into bile acids than are LpA-I/A-II-derived cholesterol esters

1993 ◽  
Vol 292 (3) ◽  
pp. 819-823 ◽  
Author(s):  
M N Pieters ◽  
G R Castro ◽  
D Schouten ◽  
P Duchateau ◽  
J C Fruchart ◽  
...  
Keyword(s):  
Bile Acid ◽  
High Density Lipoprotein ◽  
Cholesterol Ester ◽  
Density Lipoprotein ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Biliary Secretion ◽  
Cholesterol Esters ◽  
Selective Delivery

High-density lipoprotein (HDL) subclass LpA-I has been reported to promote cholesterol efflux from mouse adipose cells in vitro, whereas subclass LpA-I/A-II has no effect. To investigate whether the apolipoprotein composition of HDL plays a role in the selective delivery of cholesterol esters to the liver in vivo, we labelled HDL in its cholesterol ester moiety and separated [3H]cholesterol oleate-labelled HDL into subclasses LpA-I and LpA-I/A-II by immuno-affinity chromatography. Serum decay and liver association of LpA-I and LpA-I/A-II were compared for the apoprotein and cholesterol ester moieties. Both LpA-I and LpA-I/A-II selectively delivered cholesterol esters to the liver with similar kinetics. The kinetics of biliary secretion of processed cholesterol esters, initially associated with LpA-I or LpA-I/A-II, were studied in rats equipped with permanent catheters in bile, duodenum and heart. For both LpA-I and LpA-I/A-II, liver association was coupled to bile acid synthesis, with an increase in secretion rate during the night. During the first night period, the biliary secretion of LpA-I-derived radio-activity was significantly greater than for LpA-I/A-II. The data indicate that with both LpA-I and LpA-I/A-II selective delivery of cholesterol esters from HDL to the liver occurs, but that cholesterol esters delivered by LpA-I are more efficiently coupled to bile acid synthesis.

scholarly journals Light and electron microscopical observations of the effects of high-density lipoprotein on growth of Plasmodium falciparum in vitro

Parasitology ◽  
2004 ◽  
Vol 128 (6) ◽  
pp. 577-584 ◽  
Author(s):  
H. IMRIE ◽  
D. J. P. FERGUSON ◽  
M. CARTER ◽  
J. DRAIN ◽  
A. SCHIFLETT ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
High Density Lipoprotein ◽  
Light And Electron Microscopy ◽  
Density Lipoprotein ◽  
Acid Synthesis ◽  
High Density ◽  
High Concentrations ◽  
Electron Microscopical ◽  
Necessary And Sufficient

Human serum high-density lipoprotein (HDL) is necessary and sufficient for the short-term maintenance of Plasmodium falciparum in in vitro culture. However, at high concentrations it is toxic to the parasite. A heat-labile component is apparently responsible for the stage-specific toxicity to parasites within infected erythrocytes 12–42 h after invasion, i.e. during trophozoite maturation. The effects of HDL on parasite metabolism (as determined by nucleic acid synthesis) are evident at about 30 h after invasion. Parasites treated with HDL show gross abnormalities by light and electron microscopy.

A Bile-acid-rich High-density Lipoprotein (HDL) in Acute Hepatitis

1979 ◽  
Vol 14 (3) ◽  
pp. 267-272 ◽  
Author(s):  
G. Middelhoff ◽  
R. Mordasini ◽  
A. Stiehl ◽  
H. Greten
Keyword(s):  
Bile Acid ◽  
High Density Lipoprotein ◽  
Acute Hepatitis ◽  
Density Lipoprotein ◽  
High Density

scholarly journals Clearance from plasma of lymph chylomicrons and chylomicron remnants labelled with 125I-tyramine-cellobiose

1992 ◽  
Vol 286 (3) ◽  
pp. 937-943 ◽  
Author(s):  
H L Ly ◽  
B C Mortimer ◽  
E Baker ◽  
T G Redgrave
Keyword(s):  
High Density Lipoprotein ◽  
Lipoprotein Lipase ◽  
Bovine Milk ◽  
Density Lipoprotein ◽  
High Density ◽  
Low Density ◽  
Apolipoprotein B48 ◽  
Chylomicron Remnants

The aims of the present study were to evaluate the metabolism of chylomicrons (CM) and of CM remnants after labelling with radioactive iodine and converting the iodinated CM into remnants in vitro. Lymph CM were radiolabelled with 125I or sham-labelled with 127I by either the ICl procedure or the tyramine-cellobiose (TC) procedure, then injected into rats. The clearance from plasma of the iodinated CM was compared with control non-iodinated lipid-labelled CM. After iodination with ICl, the plasma removal of endogenously labelled CM was significantly different from non-iodinated CM, with increased uptake of CM triacylglycerols by the liver. In contrast, the clearances from plasma and the uptake by organs of radiolabelled lipids of CM iodinated by the TC method (TC-CM) were similar to control CM. About 40% of the label from 125I-TC-CM was insoluble in 50% propan-2-ol, indicating association with CM apolipoprotein B48. Only about 8% of label was lipid soluble, mostly in phosphatidylethanolamine. Radioactivity from 125I-TC-CM injected intravenously in rats was cleared rapidly and by 30 min only 20% remained in plasma, whereas 48% was recovered in the liver. After fractionation of the plasma by density-gradient ultracentrifugation, most label remained associated with d (relative density) less than 1.006 lipoproteins. In intact rats label was also found associated with the low-density and high-density lipoprotein fractions of plasma. When the liver was excluded from circulation, the recovery of label in low-density- and high-density-lipoprotein fractions was greatly decreased. CM remnants were prepared in vivo by injecting 125I-TC-CM into functionally hepatectomized donors and compared with remnants prepared in vitro by incubation with purified bovine milk lipoprotein lipase. Although remnants prepared in vitro cleared from plasma slower than remnants prepared in vivo, the size, lipid composition and apolipoprotein profile on gradient PAGE of the remnants were similar. We conclude that labelling of CM by the TC method avoided the ‘artefactual’ changes in metabolism seen after labelling by the ICl procedure. CM remnants when prepared in vitro using lipoprotein lipase were found to be similar to those prepared in vivo after injection into functionally hepatectomized rats.

scholarly journals Growth Hormone Induces Low-Density Lipoprotein Clearance but not Bile Acid Synthesis in Humans

2004 ◽  
Vol 24 (2) ◽  
pp. 349-356 ◽  
Author(s):  
Suzanne Lind ◽  
Mats Rudling ◽  
Sverker Ericsson ◽  
Hans Olivecrona ◽  
Mats Eriksson ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Bile Acid ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Low Density

scholarly journals Myostatin Knockout Regulates Bile Acid Metabolism by Promoting Bile Acid Synthesis in Cattle

Animals ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 205
Author(s):  
Di Wu ◽  
Mingjuan Gu ◽  
Zhuying Wei ◽  
Chunling Bai ◽  
Guanghua Su ◽  
...  
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Acid Metabolism ◽  
Density Lipoprotein ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Negative Regulator ◽  
Bile Acid Metabolism ◽  
Metabolomic Analysis ◽  
Metabolomics Data

Myostatin (MSTN) is a major negative regulator of skeletal muscle mass and causes a variety of metabolic changes. However, the effect of MSTN knockout on bile acid metabolism has rarely been reported. In this study, the physiological and biochemical alterations of serum in MSTN+/− and wild type (WT) cattle were investigated. There were no significant changes in liver and kidney biochemical indexes. However, compared with the WT cattle, lactate dehydrogenase, total bile acid (TBA), cholesterol, and high-density lipoprotein (HDL) in the MSTN+/− cattle were significantly increased, and glucose, low-density lipoprotein (LDL), and triglycerides (TG) were significantly decreased, indicating that MSTN knockout affected glucose and lipid metabolism and total bile acids content. Targeted metabolomic analysis of the bile acids and their derivatives was performed on serum samples and found that bile acids were significantly increased in the MSTN+/− cattle compared with the WT cattle. As the only bile acid synthesis organ in the body, we performed metabolomic analysis on the liver to study the effect of MSTN knockout on hepatic metabolism. Metabolic pathway enrichment analysis of differential metabolites showed significant enrichment of the primary bile acid biosynthesis and bile secretion pathway in the MSTN+/− cattle. Targeted metabolomics data further showed that MSTN knockout significantly increased bile acid content in the liver, which may have resulted from enhanced bile acid synthesis due to the expression of bile acid synthesis genes, cholesterol 7 alpha-hydroxylase (CYP7A1) and sterol 27-hydroxylase (CYP27A1), and upregulation in the liver of the MSTN+/− cattle. These results indicate that MSTN knockout does not adversely affect bovine fitness but regulates bile acid metabolism via enhanced bile acid synthesis. This further suggests a role of MSTN in regulating metabolism.

scholarly journals Lipoprotein cholesterol uptake mediates up-regulation of bile-acid synthesis by increasing cholesterol 7α-hydroxylase but not sterol 27-hydroxylase gene expression in cultured rat hepatocytes

1999 ◽  
Vol 341 (2) ◽  
pp. 339-346 ◽  
Author(s):  
Sabine M. POST ◽  
Jaap TWISK ◽  
L V D FITS ◽  
Elly C. M. DE WIT ◽  
Marco F. M. HOEKMAN ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bile Acid ◽  
Density Lipoprotein ◽  
Rat Hepatocytes ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Lipoprotein Cholesterol ◽  
Hydroxylase Gene ◽  
Apo E ◽  
Cultured Rat Hepatocytes

Lipoproteins may supply substrate for the formation of bile acids, and the amount of hepatic cholesterol can regulate bile-acid synthesis and increase cholesterol 7α-hydroxylase expression. However, the effect of lipoprotein cholesterol on sterol 27-hydroxylase expression and the role of different lipoproteins in regulating both enzymes are not well established. We studied the effect of different rabbit lipoproteins on cholesterol 7α-hydroxylase and sterol 27-hydroxylase in cultured rat hepatocytes. β-Migrating very-low-density lipoprotein (βVLDL) and intermediate-density lipoprotein (IDL) caused a significant increase in the intracellular cholesteryl ester content of cells (2.3- and 2-fold, respectively) at a concentration of 200 μg of cholesterol/ml, whereas high-density lipoprotein (HDL, 50% v/v), containing no apolipoprotein E (apo E), showed no effect after a 24-h incubation. βVLDL and IDL increased bile-acid synthesis (1.9- and 1.6-fold, respectively) by up-regulation of cholesterol 7α-hydroxylase activity (1.7- and 1.5-fold, respectively). Dose- and time-dependent changes in cholesterol 7α-hydroxylase mRNA levels and gene expression underlie the increase in enzyme activity. Incubation of cells with HDL showed no effect. Sterol 27-hydroxylase gene expression was not affected by any of the lipoproteins added. Transient-expression experiments in hepatocytes, transfected with a promoter-reporter construct containing the proximal 348 nucleotides of the rat cholesterol 7α-hydroxylase promoter, showed an enhanced gene transcription (2-fold) with βVLDL, indicating that a sequence important for a cholesterol-induced transcriptional response is located in this part of the cholesterol 7α-hydroxylase gene. The extent of stimulation of cholesterol 7α-hydroxylase is associated with the apo E content of the lipoprotein particle, which is important in the uptake of lipoprotein cholesterol. We conclude that physiological concentrations of cholesterol in apo E-containing lipoproteins increase bile-acid synthesis by stimulating cholesterol 7α-hydroxylase gene transcription, whereas HDL has no effect and sterol 27-hydroxylase is not affected.

scholarly journals Soybean-Derived Peptides Attenuate Hyperlipidemia by Regulating Trans-Intestinal Cholesterol Excretion and Bile Acid Synthesis

Nutrients ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 95
Author(s):  
Haksoo Lee ◽  
Eunguk Shin ◽  
Hyunkoo Kang ◽  
HyeSook Youn ◽  
BuHyun Youn
Keyword(s):  
Bile Acid ◽  
Mouse Models ◽  
Bioactive Peptides ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Blood Lipid ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Peptide Sequence ◽  
Cholesterol Excretion

Increased triglyceride, cholesterol, and low-density lipoprotein (LDL) levels cause hyperlipidemia. Despite the availability of statin-based drugs to reduce LDL levels, additional effective treatments for reducing blood lipid concentrations are required. Herein, soybean hydrolysate prepared via peptic and tryptic hydrolysis promoted trans-intestinal cholesterol excretion (TICE) by increasing ATP-binding cassette subfamily G member 5 (ABCG5) and ABCG8 expression. The peptide sequence capable of promoting TICE was determined via HPLC and LC-MS/MS. Based on this, pure artificial peptides were synthesized, and the efficacy of the selected peptides was verified using cellular and hyperlipidemic mouse models. Soybean hydrolysates, including two bioactive peptides (ALEPDHRVESEGGL and SLVNNDDRDSYRLQSGDAL), promoted TICE via the expression of ABCG5 and ABCG8 in enterocytes. They downregulated expression of hepatic cytochrome P450 family 7 subfamily A member 1 (CYP7A1) and CYP8B1 via expression of fibroblast growth factor 19 (FGF19) in a liver X receptor α (LXRa)-dependent pathway. Administration of bioactive peptides to hyperlipidemic mouse models by oral gavage reduced cholesterol levels in serum via upregulation of ABCG5 and ABCG8 expression in the proximal intestine and through fecal cholesterol excretion, upregulated FGF 15/19 expression, and suppressed hepatic bile acid synthesis. Oral administration of soybean-derived bioactive peptides elicited hypolipidemic effects by increasing TICE and decreasing hepatic cholesterol synthesis.

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