Postprandial lipemic response and lipoprotein composition in subjects with low or high cholesterol absorption efficiency

2006 ◽  
Vol 366 (1-2) ◽  
pp. 309-315 ◽  
Author(s):  
Jyrki J. Ågren ◽  
Maarit Hallikainen ◽  
Helvi Vidgren ◽  
Tatu A. Miettinen ◽  
Helena Gylling
Keyword(s):  
Cholesterol Absorption ◽  
Absorption Efficiency ◽  
High Cholesterol ◽  
Postprandial Lipemic Response ◽  
Lipoprotein Composition

Abstract 617: Intestine-Specific MTP Deficiency with ACAT2 Gene Ablation Lowers Acute Cholesterol Absorption With Chylomicrons and High-Density Lipoproteins

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Jahangir Iqbal ◽  
Mohamed Boutjdir ◽  
Lawrence L Rudel ◽  
M Mahmood Hussain
Keyword(s):  
Density Lipoprotein ◽  
Microsomal Triglyceride Transfer Protein ◽  
Cholesterol Absorption ◽  
High Density ◽  
High Density Lipoproteins ◽  
High Cholesterol ◽  
Intestinal Cholesterol Absorption ◽  
Triglyceride Accumulation ◽  
Abca1 Expression ◽  
Deficient Mice

Intestinal cholesterol absorption involves chylomicron and high density lipoprotein (HDL) pathways. Microsomal triglyceride transfer protein (MTP) and ATP binding cassette family A protein 1 (ABCA1) are critical for cholesterol transport by these pathways, respectively. Additionally, acyl Co-A:cholesterol acyltransferase 2 (ACAT2) plays an important role in cholesterol absorption. Intestinal MTP ablation significantly increased intestinal triglyceride and cholesterol levels and reduced their acute absorption. In contrast, ACAT2 deficiency had no effect on triglyceride absorption but significantly reduced cholesterol absorption. Individual deficiencies of ACAT2 and MTP reduced cholesterol absorption with chylomicrons. We hypothesized that their combined deficiency would increase cholesterol secretion with HDL; unexpectedly, their deficiency reduced secretion with both chylomicrons and HDL. Further, we observed significant reductions in intestinal ABCA1 expression in combined deficient mice. Thus, free cholesterol is unavailable for secretion by the HDL pathway in these mice. We speculate that reductions in ABCA1 expression and HDL secretion might be secondary to massive triglyceride accumulation associated with intestinal MTP deficiency. Besides its role in cholesterol absorption, ACAT2 deficiency causes mild hypertriglyceridemia and reduces steatosis in mice fed high cholesterol diets by increasing hepatic lipoprotein production by unknown mechanisms. We show that this phenotype is preserved in the absence of intestinal MTP in ACAT2 deficient mice fed a Western diet. Further, we observed increases in hepatic MTP activity in these mice. Thus, ACAT2 deficiency might increase MTP expression to avoid steatosis. Therefore, ACAT2 inhibition might avert steatosis associated with high cholesterol diets by increasing MTP expression.

scholarly journals Vitamin A Absorption Determined in Rats Using a Plasma Isotope Ratio Method

2020 ◽  
Vol 150 (7) ◽  
pp. 1977-1981 ◽  
Author(s):  
Michael H Green ◽  
Joanne Balmer Green
Keyword(s):  
Vitamin A ◽  
Oral Dose ◽  
Isotope Ratio ◽  
Cholesterol Absorption ◽  
Absorption Efficiency ◽  
Intravenous Dose ◽  
Ratio Method ◽  
Sprague Dawley ◽  
Retinyl Acetate ◽  
Dose Fraction

ABSTRACT Background Better methods are needed for determining vitamin A absorption efficiency. Objective Our objective was to measure vitamin A absorption in rats by adapting a plasma isotope ratio method previously used to determine cholesterol absorption. Methods Male Sprague-Dawley rats [n = 14; 340 ± 16 g (mean ± SD)] received an oral tracer dose of [3H]retinyl acetate in oil plus an intravenous dose of [14C]vitamin A–labeled lymph prepared in a donor rat that had received [14C]retinyl acetate intraduodenally. Blood samples were collected on days 1, 2, 3, 6, 9, and 12, and plasma was analyzed for 3H and 14C; vitamin A absorption was calculated for each sample as (fraction of oral dose/fraction of intravenous dose) × 100. Radioactivity was also measured in feces and urine collected as pools on days 3, 6, 9, and 12 and in liver and remaining carcass on day 12. Results Vitamin A absorption calculated as the plasma isotope ratio was >100% on day 1, 78% ± 5% on day 6, 76% ± 5% on day 9, and 74% ± 5% on day 12; fitting the data to an exponential function plus a constant predicted an absorption of 75% by day 14. Recovery of the oral dose in feces (day 0 to day 6) was low (6.2% ± 0.84%, n = 10) and the mean isotope ratio in day 9–12 urine pool was lower than that in plasma. Conclusions The plasma isotope ratio holds promise for estimating vitamin A absorption, but additional work is needed to determine how long studies need to be and if the doses should be administered simultaneously. For application of this method in humans, artificial chylomicrons labeled with a stable isotope of retinyl acetate could be used for the intravenous dose, with a different isotope required for the oral dose.

Role of intestinal sterol transporters Abcg5, Abcg8, and Npc1l1 in cholesterol absorption in mice: gender and age effects

2006 ◽  
Vol 290 (2) ◽  
pp. G269-G276 ◽  
Author(s):  
Li-Ping Duan ◽  
Helen H. Wang ◽  
Akira Ohashi ◽  
David Q.-H. Wang
Keyword(s):  
Molecular Mechanisms ◽  
Apical Membrane ◽  
Cholesterol Absorption ◽  
Absorption Efficiency ◽  
Biliary Cholesterol ◽  
Intestinal Cholesterol Absorption ◽  
Gender And Age ◽  
Multistep Process ◽  
17Β Estradiol

Recent studies have indicated that intestinal cholesterol absorption is a multistep process, which is regulated by multiple genes at the enterocyte level. However, the molecular mechanisms whereby there are gender differences in intestinal cholesterol absorption efficiency and the efficiency of cholesterol absorption increases with age have not yet been fully understood. To explore whether aging increases cholesterol absorption via intestinal sterol transporters, we studied the higher cholesterol-absorbing C57L/J vs. the lower cholesterol-absorbing AKR/J mice at 8 (young adult), 36 (older adult), and 50 (aged) wk of age. To test the hypothesis that estrogen receptor (ER )α plays an important regulatory role in cholesterol absorption, we investigated the gonadectomized mice of both genders treated with 17β-estradiol-releasing pellets at 0, 3, or 6 μg/day and antiestrogenic ICI 182,780 at 125 μg/day. We found that hepatic outputs of biliary cholesterol were significantly increased with age and in response to high levels of estrogen. Aging significantly enhances cholesterol absorption by suppressing expression of the jejunal and ileal sterol efflux transporters [ATP-binding cassette ( Abc) g5 and Abcg8] and upregulating expression of the putative duodenal and jejunal sterol influx transporter Npc1l1. Estrogen significantly augmented cholesterol absorption mostly due to an upregulated expression of intestinal Npc1l1, Abcg5, and Abcg8 via the intestinal ERα pathway, which can be fully abolished by the antagonist. We conclude that ERα activated by estrogen and aging enhances cholesterol absorption by increasing biliary lipid output and mediating intestinal sterol transporters favoring influx of intraluminal cholesterol molecules across the apical membrane of the enterocyte.

Natural Dietary Phytosterols

2015 ◽  
Vol 98 (3) ◽  
pp. 679-684 ◽  
Author(s):  
Susan B Racette ◽  
Xiaobo Lin ◽  
Lina Ma ◽  
Richard E Ostlund, Jr
Keyword(s):  
Ldl Cholesterol ◽  
Cholesterol Metabolism ◽  
Disease Risk ◽  
Cholesterol Biosynthesis ◽  
Cholesterol Absorption ◽  
Absorption Efficiency ◽  
Whole Body ◽  
Natural Diet ◽  
Cholesterol Excretion ◽  
Heart Disease Risk

Abstract Most clinical phytosterol studies are performed by adding purified supplements to smaller phytosterol amounts present in the natural diet. However, natural dietary phytosterols themselves may also have important effects on cholesterol metabolism. Epidemiological work using food frequency questionnaires to estimate dietary intake suggest that extremes of normal consumption may be associated with 3–14% changes in LDL cholesterol. Standardized food databases do not have enough phytosterol values to allow calculation of phytosterol intake for individuals outside of specialized studies. Natural diets contain phytosterol amounts ranging from less than 60 mg/2000 kcal to over 500 mg/2000 kcal. Physiological studies in which whole body cholesterol metabolism is investigated show large effects of natural dietary phytosterols on cholesterol absorption efficiency, cholesterol biosynthesis and cholesterol excretion which exceed the magnitude of changes in LDL cholesterol. The dual effects of natural phytosterols on both LDL-C and whole body cholesterol metabolism need to be considered in relating them to potential protection from coronary heart disease risk.

Soybean germ oil reduces blood cholesterol by inhibiting cholesterol absorption and enhancing bile acid excretion

2019 ◽  
Vol 10 (4) ◽  
pp. 1836-1845 ◽  
Author(s):  
Hanyue Zhu ◽  
Jingnan Chen ◽  
Zouyan He ◽  
Wangjun Hao ◽  
Jianhui Liu ◽  
...  
Keyword(s):  
Bile Acid ◽  
Cholesterol Absorption ◽  
Blood Cholesterol ◽  
High Cholesterol Diet ◽  
Cholesterol Diet ◽  
Acid Excretion ◽  
High Cholesterol ◽  
Bile Acid Excretion

Soybean germ oil is beneficial in management of hypercholesterolemia in hamsters fed a high cholesterol diet.

Serum Levels, Absorption Efficiency, Faecal Elimination and Synthesis of Cholesterol during Increasing Doses of Dietary Sitostanol Esters in Hypercholesterolaemic Subjects

1994 ◽  
Vol 87 (1) ◽  
pp. 61-67 ◽  
Author(s):  
H. T. Vanhanen ◽  
J. Kajander ◽  
H. Lehtovirta ◽  
T. A. Miettinen
Keyword(s):  
Dietary Fat ◽  
Rapeseed Oil ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Serum Levels ◽  
Cholesterol Absorption ◽  
Absorption Efficiency ◽  
Lipoprotein Cholesterol ◽  
Low Density ◽  
Low Density Lipoprotein Cholesterol

1. Serum cholesterol reduction and changes in cholesterol metabolism were studied during rapeseed oil feeding without and with increasing amounts of sitostanol trans-esterified with rapeseed oil fatty acids and dissolved in rapeseed oil mayonnaise. Fifteen mildly hypercholesterolaemic subjects replaced 50 g of their usual dietary fat by 50 g of rapeseed oil fat mayonnaise for 6 weeks followed by randomization so that eight subjects continued on rapeseed oil mayonnaise alone (control group) for 15 weeks and seven on rapeseed oil mayonnaise with a small dose of sitostanol ester (800 mg/day of sitostanol) for 9 weeks followed by 6 weeks with higher dose of sitostanol ester (2000 mg/day of sitostanol). 2. During the rapeseed oil period the reduction in serum low-density lipoprotein cholesterol was 14% from the home diet. The control-adjusted reduction by the low sitostanol ester dose was 7.4% (not significant) and by the higher dose it was 15.7%. 3. The low dose of sitostanol ester had no consistent effect on cholesterol precursors or cholestanol in serum, reduced serum levels of campesterol and sitosterol by 28.2% and 23.6%, respectively, and reduced cholesterol absorption efficiency significantly from 28.7% to 23.4%. In accordance, faecal excretion of neutral and particularly endogenous neutral sterols increased (16.7% and 19.7%, respectively), but faecal cholesterol elimination and cholesterol synthesis were only insignificantly increased. 4. During the high dose of sitostanol ester the high-density lipoprotein- to low-density lipoprotein-cholesterol ratio increased. Serum levels of cholesterol precursor sterols, indicators of cholesterol synthesis, increased up to 12%, whereas those of cholestanol were slightly decreased and those of campesterol and sitosterol values were further reduced by 30% and 25.6%, respectively. 5. Associations of serum plant sterols and cholesterol precursors with cholesterol absorption efficiency and synthesis and the sitostanol-ester-induced changes in serum campesterol and lathosterol proportions with those in serum low-density lipoprotein-cholesterol suggest that reduced cholesterol absorption efficiency was the main reason for cholesterol reduction and that there was a compensatory increase in cholesterol synthesis. 6. The findings indicate that sitostanol ester dissolved in dietary fat is apparently unabsorbable and interferes with sterol absorption so that the serum levels of cholesterol and low-density lipoprotein-cholesterol are reduced to the extent that sitostanol ester-fat mixture in reasonable daily amounts can be recommended to replace dietary fat for lowering of serum cholesterol.

scholarly journals Differential Expression of Intestinal Genes in Opossums with High and Low Responses to Dietary Cholesterol

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Jeannie Chan ◽  
Rampratap S. Kushwaha ◽  
Jane F. VandeBerg ◽  
Jelica Gluhak-Heinrich ◽  
John L. VandeBerg
Keyword(s):  
Low Density Lipoprotein ◽  
Dietary Cholesterol ◽  
Density Lipoprotein ◽  
Cholesterol Absorption ◽  
Low Density ◽  
Mrna Levels ◽  
High Cholesterol ◽  
Phospholipase Activity ◽  
Low Responders ◽  
High Responders

High and low responding opossums (Monodelphis domestica) differ in their plasma very low density lipoprotein and low density lipoprotein (VLDL+LDL) cholesterol concentrations when they consume a high cholesterol diet, which is due in part to absorption of a higher percentage of dietary cholesterol in high responders. We compared the expression of a set of genes that influence cholesterol absorption in high and low responders fed a basal or a high cholesterol and low fat (HCLF) diet. Up-regulation of theABCG5,ABCG8, andIBABPgenes by the HCLF diet in high and low responders may reduce cholesterol absorption to maintain cholesterol homeostasis. Differences in expression of the phospholipase genes (PLA2andPLB) and phospholipase activity were associated with differences in cholesterol absorption when opossums were fed cholesterol-enriched diets. HigherPLA2andPLBmRNA levels and higher phospholipase activity may increase cholesterol absorption in high responders by enhancing the release of cholesterol from bile salt micelles for uptake by intestinal cells.

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