scholarly journals Dietary cholesterol lowers the activity of butyrylcholinesterase (EC3.1.1.8), but elevates that of esterase-1 (EC3.1.1.1) in plasma of rats

1993 ◽  
Vol 70 (3) ◽  
pp. 721-726 ◽  
Author(s):  
H. A. Van Lith ◽  
A. C. Beynen
Keyword(s):  
Cholesterol Metabolism ◽  
Plasma Cholesterol ◽  
Dietary Cholesterol ◽  
Cholesterol Absorption ◽  
Intestinal Cholesterol Absorption ◽  
Carbohydrate Source ◽  
Butyrylcholinesterase Activity

The question addressed is whether an increased intake of cholesterol affects esterase-1 (EC3.1.1.1; ES-1) and butyrylcholinesterase (EC3.1.1.8) activity in plasma. Rats were fed on a purified diet either without or with cholesterol (10 g/kg) added at the expense of the carbohydrate source. Dietary cholesterol significantly decreased plasma butyrylcholinesterase activity, but raised plasma ES-1 activity. Evidence is discussed, suggesting that plasma butyrylcholinesterase is involved in plasma cholesterol metabolism, whereas esterase-1 is involved in intestinal cholesterol absorption.

scholarly journals The hypocholesterolaemic effects of sitostanol in the guinea pig are in part related to changes in hepatic lipids and lipoprotein composition

2001 ◽  
Vol 85 (2) ◽  
pp. 165-172 ◽  
Author(s):  
Tripurasundari Ramjiganesh ◽  
Suheeta Roy ◽  
Jonathan C. McIntyre ◽  
Maria Luz Fernandez
Keyword(s):  
Total Cholesterol ◽  
Guinea Pigs ◽  
Corn Oil ◽  
Cholesterol Metabolism ◽  
Plasma Cholesterol ◽  
Dietary Cholesterol ◽  
Cholesterol Absorption ◽  
Negative Control ◽  
Control Group ◽  
Hepatic Cholesterol

To evaluate some of the mechanisms involved in the plasma cholesterol lowering of sitostanol (SI), male Hartley guinea pigs were fed diets containing cholesterol (0.25 g/100 g) and four doses of SI: either 0 (control), 0.75, 1.5 or 2.25 g/100 g. In addition a negative control (-C) group with dietary cholesterol (0.04 g/100 g) was included. Corn oil was used as the source of fat and the contribution of fat energy was 35 %. Plasma total cholesterol was 43, 49 and 53 % (P<0.0001) lower after SI intake compared to the control. Plasma LDL concentrations were 47, 53 and 61 % lower with increasing doses of SI. In addition, intake of SI resulted in 26–42 % lower hepatic total cholesterol. Hepatic esterified cholesterol and triacylglycerols were 32–60 % and 55–61 % lower after SI intake. SI intake resulted in favourable plasma and hepatic cholesterol concentrations similar to those in guinea pigs fed low levels of dietary cholesterol (-C). The LDL obtained from the control group had a higher number of molecules of free and esterified cholesterol than the SI groups. SI intake resulted in 69–71 % higher cholesterol excretion compared to the control. SI treatment enhanced the total faecal neutral sterol excretion by 54–58 % compared to control and by 70–76 % compared to the (-C) group. These results suggest that SI might have its hypocholesterolaemic effect by reducing cholesterol absorption, which results in lower concentration of cholesterol in liver. This reduction in hepatic cholesterol might possibly alter hepatic cholesterol metabolism and affect lipoprotein concentration and composition.

scholarly journals A role for NPC1 and NPC2 in intestinal cholesterol absorption – the hypothesis gutted

2007 ◽  
Vol 408 (1) ◽  
Author(s):  
Laura Liscum
Keyword(s):  
Endoplasmic Reticulum ◽  
Dietary Cholesterol ◽  
Cholesterol Absorption ◽  
Cholesterol Transport ◽  
Intestinal Epithelial ◽  
Intestinal Cholesterol Absorption ◽  
Biochemical Journal ◽  
Good Target ◽  
Type C ◽  
Niemann Pick

Dietary and biliary cholesterol are taken up by intestinal epithelial cells and transported to the endoplasmic reticulum. At the endoplasmic reticulum, cholesterol is esterified, packaged into chylomicrons and secreted into the lymph for delivery to the bloodstream. NPC1L1 (Niemann–Pick C1-like 1) is a protein on the enterocyte brush-border membrane that facilitates cholesterol absorption. Cholesterol's itinerary as it moves to the endoplasmic reticulum is unknown, as is the identity of any cellular proteins that facilitate the movement. Two proteins that play an important role in intracellular cholesterol transport and could potentially influence NPC1L1-mediated cholesterol uptake are NPC1 and NPC2 (Niemann–Pick type C disease proteins 1 and 2). In this issue of the Biochemical Journal, Dixit and colleagues show that the absence or presence of NPC1 and NPC2 has no effect on intestinal cholesterol absorption in the mouse. Thus neither protein fills the gap in our knowledge of intra-enterocyte cholesterol transport. Furthermore, the NPC1/NPC2 pathway would not be a good target for limiting the uptake of dietary cholesterol.

scholarly journals Dietary Cholesterol Contained in Whole Eggs Is Not Well Absorbed and Does Not Acutely Affect Plasma Total Cholesterol Concentration in Men and Women: Results from 2 Randomized Controlled Crossover Studies

Nutrients ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1272 ◽  
Author(s):  
Jung Kim ◽  
Wayne Campbell
Keyword(s):  
Total Cholesterol ◽  
Plasma Cholesterol ◽  
Dietary Cholesterol ◽  
Cholesterol Absorption ◽  
Blood Cholesterol ◽  
Cholesterol Concentration ◽  
Total Cholesterol Concentration ◽  
Plasma Total Cholesterol ◽  
Crossover Studies ◽  
Whole Egg

Whole egg is a food source of dietary cholesterol and inconsistent research findings exist about the effect of dietary cholesterol from whole egg on blood cholesterol concentration. We assessed the effect of co-consuming cooked whole egg (CWE) on dietary cholesterol absorption from two randomized-crossover studies. For study 1, 16 men consumed raw vegetables with no egg, 75 g CWE, or 150 g CWE. For study 2, 17 women consumed cooked vegetables with no egg or 100 g CWE. Triacylglycerol-rich lipoprotein fractions (TRL) were isolated from collected blood. In study 1, total-cholesterol areas under the curve (AUC)0–10h in TRL were not different but triacylglycerol AUC0–10h in TRL was greater for 150 g CWE vs. 75 g CWE and no egg. Similarly, in study 2, total-cholesterol AUC0–10h in TRL was not different but triacylglycerol AUC0–10h in TRL was greater for 100 g CWE vs. no egg. In both studies, whole egg consumption did not affect plasma total-cholesterol AUC0–10h, while triacylglycerol AUC0–10h was increased. These results suggest that the dietary cholesterol in whole egg was not well absorbed, which may provide mechanistic insight for why it does not acutely influence plasma total-cholesterol concentration and is not associated with longer-term plasma cholesterol control.

Dietary cholesterol: from physiology to cardiovascular risk

2011 ◽  
Vol 106 (1) ◽  
pp. 6-14 ◽  
Author(s):  
Jean-Michel Lecerf ◽  
Michel de Lorgeril
Keyword(s):  
Plasma Cholesterol ◽  
Dietary Cholesterol ◽  
Ldl Receptor ◽  
Epidemiological Data ◽  
Cholesterol Absorption ◽  
Cholesterol Content ◽  
Biological Data ◽  
Related Protein ◽  
Cvd Risk ◽  
Nutritional Factors

Dietary cholesterol comes exclusively from animal sources, thus it is naturally present in our diet and tissues. It is an important component of cell membranes and a precursor of bile acids, steroid hormones and vitamin D. Contrary to phytosterols (originated from plants), cholesterol is synthesised in the human body in order to maintain a stable pool when dietary intake is low. Given the necessity for cholesterol, very effective intestinal uptake mechanisms and enterohepatic bile acid and cholesterol reabsorption cycles exist; conversely, phytosterols are poorly absorbed and, indeed, rapidly excreted. Dietary cholesterol content does not significantly influence plasma cholesterol values, which are regulated by different genetic and nutritional factors that influence cholesterol absorption or synthesis. Some subjects are hyper-absorbers and others are hyper-responders, which implies new therapeutic issues. Epidemiological data do not support a link between dietary cholesterol and CVD. Recent biological data concerning the effect of dietary cholesterol on LDL receptor-related protein may explain the complexity of the effect of cholesterol on CVD risk.

scholarly journals Cholesterolaemic Effects of the Saturated Fatty Acids of Palm Oil

1994 ◽  
Vol 15 (2) ◽  
pp. 1-7 ◽  
Author(s):  
Pramod Khosla ◽  
K. C. Hayes
Keyword(s):  
Fatty Acids ◽  
Palmitic Acid ◽  
Palm Oil ◽  
Cholesterol Metabolism ◽  
Plasma Cholesterol ◽  
Saturated Fatty Acids ◽  
Dietary Cholesterol ◽  
Dietary Fatty Acids ◽  
Potential Health ◽  
Minimal Impact

Dietary saturated fats are implicated as a major risk factor in hypercholesterolaemia and cardiovascular disease. Palm oil is a major source of the world's supply of oils and fats, but because of its relatively high content of saturated fatty acids (principally palmitic acid), its consumption has come under intense scrutiny over the last decade owing to potential health implications. Based on studies carried out more than thirty years ago, the hypothesis was developed that lauric, myristic, and palmitic acid were the three principal cholesterol-raising saturated fatty acids. Since palmitic acid is the most abundant fatty acid in the diet, the cholesterol-raising effect of all saturated fatty acids was accordingly assigned to it. However, recent studies from both humans and experimental animals suggest that not all saturated fatty acids are cholesterol-raising. When all dietary fatty acids are equalized, with the exception of the two being tested, palmitic acid appears to have no impact on the plasma cholesterol in normocholesterolaemic subjects when dietary cholesterol intake is below a certain critical level (400 mg per day). Only when cholesterol consumption exceeds this level, or when hypercholesterolaemic subjects are studied, does palmitic acid appear to increase the plasma cholesterol. These differential effects of palmitic acid on plasma cholesterol are thought to reflect differences in LDL-receptor status. Collectively these data imply that, for most of the world's population, palm oil would be an inexpensive and readily metabolized source of dietary energy with minimal impact on cholesterol metabolism.

scholarly journals SREBP2 mediates the modulation of intestinal NPC1L1 expression by curcumin

2011 ◽  
Vol 301 (1) ◽  
pp. G148-G155 ◽  
Author(s):  
Pradeep Kumar ◽  
Pooja Malhotra ◽  
Ke Ma ◽  
Amika Singla ◽  
Omar Hedroug ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Promoter Activity ◽  
Plasma Cholesterol ◽  
Biological Effects ◽  
Cholesterol Absorption ◽  
Inhibitory Effect ◽  
Cholesterol Homeostasis ◽  
Cholesterol Esterification ◽  
Dependent Manner ◽  
Intestinal Cholesterol Absorption

Curcumin, the major phenolic compound in the spice turmeric, exhibits numerous biological effects, including lowering plasma cholesterol and preventing diet-induced hypercholesterolemia. The mechanisms underlying the hypocholesterolemic effect of curcumin are not fully understood. In this regard, intestinal Niemann-Pick C1-like 1 (NPC1L1) cholesterol transporter, the molecular target of intestinal cholesterol absorption inhibitor ezetimibe, plays an essential role in the maintenance of cholesterol homeostasis. The current studies were designed to investigate the effect of curcumin on NPC1L1 function, expression, and promoter activity in intestinal Caco-2 monolayers. NPC1L1 function was evaluated by the measurement of ezetimibe-sensitive [3H]cholesterol esterification. Relative abundance of NPC1L1 mRNA and protein was evaluated by real-time PCR and Western blotting, respectively. Luciferase assays were used to measure NPC1L1 promoter activity. Our results showed that curcumin significantly inhibited ezetimibe-sensitive cholesterol esterification in a dose-dependent manner with a maximum decrease (by 52% compared with control) occurring at 50 μM concentration. Curcumin treatment of Caco-2 monolayers also significantly decreased NPC1L1 mRNA and protein expression. Similarly, the promoter activity of the NPC1L1 gene was inhibited significantly (55%) by 50 μM curcumin. The decrease in NPC1L1 promoter activity by curcumin was associated with a reduction in the expression and the DNA-binding activity of the sterol response element-binding protein 2 (SREBP2) transcription factor. Furthermore, the overexpression of active SREBP2 protected NPC1L1 from the inhibitory effect of curcumin. Our studies demonstrate that curcumin directly modulates intestinal NPC1L1 expression via transcriptional regulation and the involvement of SREBP2 transcription factor.

Plasma Non-cholesterol Sterols as Markers of Cholesterol Synthesis and Intestinal Absorption: A Critical Review

2020 ◽  
Vol 26 (40) ◽  
pp. 5152-5162
Author(s):  
Eder Carlos Rocha Quintão
Keyword(s):  
Intestinal Absorption ◽  
Cholesterol Synthesis ◽  
Cholesterol Metabolism ◽  
Plasma Concentrations ◽  
Cholesterol Absorption ◽  
Population Based ◽  
Whole Body ◽  
Intestinal Lumen ◽  
Intestinal Cholesterol Absorption ◽  
Artery Disease

Plasma concentrations of phytosterols and non-cholesterol sterol precursors of cholesterol synthesis have been used as markers of intestinal cholesterol absorption and synthesis in inherited and secondary dyslipidemias and in population-based investigations to evaluate the risk for cardiovascular disease, respectively. The method aims at replacing initial research procedures such as the use of stable isotopes associated with fecal steroid balance, which are limited by the high cost and tedious procedures. However, we show in this review that numerous results obtained with serum sterol measurements are contradictory. In this regard, the following points are discussed: 1) how phytosterols relate to atherosclerosis considering that defects in biliary output or in the transport of phytosterols from the intestinal mucosa back into the intestinal lumen provide increased content of phytosterols and other sterols in plasma and tissues, thus not allowing to conclude that their presence in arteries and atheromas represents the etiology of atherosclerosis; 2) serum non-cholesterol sterols as markers of cholesterol synthesis and absorption, such as cholestanol, present discrepant results, rendering them often inadequate to identify cases of coronary artery disease as well as alterations in the whole body cholesterol metabolism; 3) such methods of measurement of cholesterol metabolism are confounded by factors like diabetes mellitus, body weight and other pathologies including considerable hereditary hyperlipidemias biological variabilities that influence the efficiency of synthesis and intestinal absorption of cholesterol.

The role of diet during development on the regulation of adult cholesterol homeostasis

1985 ◽  
Vol 63 (5) ◽  
pp. 557-564 ◽  
Author(s):  
Sheila M. Innis
Keyword(s):  
Cholesterol Metabolism ◽  
Plasma Cholesterol ◽  
Dietary Cholesterol ◽  
Cholesterol Homeostasis ◽  
Cholesterol Levels ◽  
Effective Training ◽  
Cholesterol Intake ◽  
Lower Plasma Cholesterol ◽  
Altered Metabolism

Atherosclerosis is believed to begin early in life and to develop over several decades. Elevated plasma cholesterol is a major contributing factor. Studies in animals have shown that manipulation of cholesterol metabolism during its development in pre-and early post-natal life can permanently alter cholesterol synthesis and catabolism to favour lower plasma cholesterol levels in the adult faced with a high dietary cholesterol intake. Although the mechanisms and pathways involved are likely to be different, "metabolic training" can occur as a result of both the diet fed to the mother during gestation and lactation and from the diet fed to the animal itself in early life. The presence of cholesterol itself in the suckling diet does not appear to confer any lasting improvement to cholesterol handling in either man or animals. Although much research is still required to define the time in development for effective training of specific steps in cholesterol metabolism and the primary site and mechanism of permanently altered metabolism, significant progress has been made. These studies will form the basis of this review.

Abstract 129: Liver-Specific and Intestine-Specific ACAT2 Knockout Mice Are Equally Protected from Diet-Induced Hepatic Cholesterol Accumulation

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Jun Zhang ◽  
Kathryn Kelley ◽  
Stephanie Marshall ◽  
Matthew Davis ◽  
Martha Wilson ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Plasma Cholesterol ◽  
Dietary Cholesterol ◽  
Cholesterol Absorption ◽  
Cholesterol Homeostasis ◽  
Cholesterol Accumulation ◽  
Very Low Density Lipoproteins ◽  
Plasma Triglycerides ◽  
Hepatic Lipid Accumulation ◽  
Vldl Cholesterol

Acyl-CoA:cholesterol acyltransferase 2 (ACAT2) is exclusively expressed in the small intestine and liver. ACAT2 facilitates the movement of cholesterol among tissues by generating cholesteryl ester (CE) for packaging into newly synthesized chylomicrons and very low-density lipoproteins (VLDL). In these studies we investigated whether CE derived from either the intestine or liver would differentially affect hepatic and plasma cholesterol homeostasis. For this purpose, we generated both liver-specific (ACAT2L-/L-) and intestine-specific (ACAT2SI-/SI-) ACAT2 knockout mice, and studied dietary cholesterol-induced hepatic lipid accumulation and hypercholesterolemia. Interestingly, diet-induced accumulation of hepatic CE was similarly decreased in both ACAT2L-/L- and ACAT2SI-/SI- mice, and free cholesterol did not build up in the liver. Compared with control mice, both ACAT2L-/L- and ACAT2SI-/SI- mice had lower levels of plasma VLDL-cholesterol but higher plasma triglycerides. ACAT2SI-/SI- but not ACAT2L-/L- mice had blunted cholesterol absorption. Collectively, both ACAT2L-/L- and ACAT2SI-/SI- mice were equally protected from diet-induced hepatic CE accumulation and hypercholesterolemia. These results suggest that inhibition of either intestinal or hepatic ACAT2 improves atherogenic hyperlipidemia and limits hepatic CE accumulation in mice, indicating that inhibition of ACAT2 expression in either tissue likely would be beneficial for atheroprotection.

Absorption and metabolism of cholesterol in familial hypercholesterolemia

1989 ◽  
Vol 76 (3) ◽  
pp. 297-301 ◽  
Author(s):  
Helena Gylling ◽  
Tatu A. Miettinen
Keyword(s):  
Cholesterol Synthesis ◽  
Familial Hypercholesterolaemia ◽  
Cholesterol Metabolism ◽  
Low Density Lipoprotein ◽  
Dietary Cholesterol ◽  
Density Lipoprotein ◽  
Cholesterol Absorption ◽  
Lipoprotein Cholesterol ◽  
Low Density ◽  
Cholesterol Intake

1. The present study investigated the role of intestinal cholesterol absorption in the regulation of cholesterol metabolism and serum lipoprotein levels in 22 patients with heterozygous familial hypercholesterolaemia on low to normal cholesterol intake. 2. The results showed that the higher the dietary cholesterol absorption, the lower was the overall synthesis of cholesterol. Efficient cholesterol absorption actually reduced the elimination of cholesterol as faecal neutral sterols but not consistently as bile acids. 3. In multifactorial analysis, body mass index and dietary plant sterols were negatively associated with cholesterol absorption, but were unrelated to cholesterol synthesis. 4. Fractional cholesterol absorption was related only to the serum very-low-density triacylglycerol level. It was not associated with the total or low-density lipoprotein cholesterol levels. On the other hand, cholesterol synthesis was significantly associated with the serum concentrations of very-low-density lipoprotein and intermediate-density lipoprotein cholesterol and triacylglycerols, and with those of low-density lipoprotein triacylglycerols. 5. In conclusion, dietary cholesterol absorption is an essential regulator of cholesterol homoeostasis in familial hypercholesterolaemia, even in patients on low cholesterol intake.

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