The Lipids and Lipoproteins of Human Peripheral Lymph, with Observations on the Transport of Cholesterol from Plasma and Tissues into Lymph

1973 ◽  
Vol 45 (3) ◽  
pp. 313-329 ◽  
Author(s):  
D. Reichl ◽  
L. A. Simons ◽  
N. B. Myant ◽  
J. J. Pflug ◽  
G. L. Mills

1. The lipids and lipoproteins of lymph obtained from the dorsum of the foot were examined in seven human subjects. 2. The concentration of total cholesterol in lymph was about one-tenth that in plasma and was significantly correlated with the plasma total cholesterol concentration. The ratio of esterified to total cholesterol in lymph was similar to that in plasma. 3. Triglyceride was detectable in lymph, but the concentration was less than one-tenth that in plasma and was unrelated to the plasma triglyceride concentration. 4. No lipase activity was detectable in lymph, either before or after intravenous injection of heparin. 5. Cholesterol-esterifying activity was detected in four samples of lymph. 6. The major lipoprotein antigens of human plasma (apo-A, apo-B and apo-C) were present in whole lymph, but their distribution in fractions of different density was different from that in plasma. 7. [14C]Cholesterol, injected intravenously, appeared in lymph within 30 min of the injection, indicating that some of the cholesterol in lymph is derived directly from plasma. 8. At intervals greater than 29 days after a single intravenous injection of [14C]-cholesterol, the specific radioactivity of lymph cholesterol was greater than that of plasma cholesterol, indicating that some of the cholesterol in lymph is derived from tissue pools of cholesterol with slow turnover.

1976 ◽  
Vol 50 (4) ◽  
pp. 307-310
Author(s):  
C. D. Moutafis ◽  
N. B. Myant

1. The specific radioactivity of [14C]cholesterol in plasma and in serial biopsies of muscle and skin was measured in Rhesus monkeys for 156 days after a single intravenous injection of [14C]cholesterol. 2. Analysis of the specific radioactivity—time curves in terms of a two-compartment system indicated that all the cholesterol of muscle is exchangeable with the plasma cholesterol and that local synthesis does not contribute significantly to the cholesterol in muscle. 3. Analysis of the curve for specific radioactivity of skin cholesterol suggested the presence of a small pool of cholesterol with slow turnover. A contribution to skin cholesterol from local synthesis could not be excluded.


1999 ◽  
Vol 58 (3) ◽  
pp. 551-557 ◽  
Author(s):  
Baukje de Roos ◽  
Janet K. Sawyer ◽  
Martijn B. Katan ◽  
Lawrence L. Rudel

Cafestol and kahweol, coffee lipids present in unfiltered coffee brews, potently increase LDL-cholesterol concentration in human subjects. We searched for an animal species in which cafestol similarly increases LDL-cholesterol. Such an animal model could be used subsequently as a model to study the mechanism of action of cafestol and kahweol. Cafestol and kahweol increased serum lipids in African green monkeys (Cercopithecus aethiops), cebus (Cebus apella) and rhesus (Macaca mulatta) monkeys, hamsters, rats and gerbils differently from the increase in human subjects. In African green monkeys, the rise in total cholesterol was less pronounced than that in human subjects. In addition, the increase in total cholesterol was predominantly due to a rise in HDL-cholesterol rather than LDL-cholesterol. Thus, the rise in plasma lipids might illustrate the mechanism in these monkeys rather than the mechanism in human subjects. In other animal species, cafestol and kahweol did not raise cholesterol consistently. The variability in effects on serum lipids could not be explained by the mode of administration or dose of diterpenes, nor by the amount of cholesterol in the diet. In conclusion, we did not find an animal model in which cafestol and kahweol elevate plasma lipoproteins to the same extent as in human subjects. For the time being, therefore, studies on the mechanism of action should be done preferably in human subjects.


1975 ◽  
Vol 229 (2) ◽  
pp. 365-369 ◽  
Author(s):  
JC Swaner ◽  
WE Connor

After the establishment of a relatively linear decay curve for plasma [4-14C]cholesterol, rabbits were starved for 26-32 days. The plasma cholesterol concentration increased 400% during starvation. Concurrently, the plasma triglyceride level declined by 50%. While the plasma cholesterol was rising, the cholesterol specific radioactivity of the plasma remained unchanged in starved animals, but in control animals the plasma cholesterol specific radioactivity declined substantially. The cholesterol content of the liver and adipose tissue increased with starvation. The cholesterol specific radioactivities relative to plasma for adipose tissue were lower in the starved animals versus controls. These results support the hypothesis that cholesterol stored in the lipid droplet of the adipose tissue cell is released into plasma and is the chief source of the hypercholesterolemia observed during complete caloric starvation. Cholesterol metabolism in the starved animal can be depicted as a virtually closed system in both the input from biosynthesis and diet being low or zero and the output likewise being close to zero.


1968 ◽  
Vol 46 (8) ◽  
pp. 859-863 ◽  
Author(s):  
B. B. Migicovsky

The supernatant from a homogenate of rat liver was incubated in a system containing 14C-acetate. The mixture was then saponified, the cholesterol isolated as the digitonide, and its radioactivity determined. When glycerol (water control) was a constituent of the incubation mixture, less radioactivity appeared in the digitonide. Under the same conditions, glycerol did not apparently inhibit the incorporation of 14C-mevalonate into liver cholesterol. When rats were given glycerol or glucose by mouth then 14C-acetate intraperitoneally, the total cholesterol radioactivity, specific radioactivity, and in most cases the serum cholesterol concentration, were all lower in those rats that had been given the glycerol.


Nutrients ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1272 ◽  
Author(s):  
Jung Kim ◽  
Wayne Campbell

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.


2020 ◽  
Vol 150 (8) ◽  
pp. 2023-2030 ◽  
Author(s):  
Jaume Amengual ◽  
Johana Coronel ◽  
Courtney Marques ◽  
Celia Aradillas-García ◽  
Juan Manuel Vargas Morales ◽  
...  

ABSTRACT Background Plasma cholesterol is one of the strongest risk factors associated with the development of atherosclerotic cardiovascular disease (ASCVD) and myocardial infarction. Human studies suggest that elevated plasma β-carotene is associated with reductions in circulating cholesterol and the risk of myocardial infarction. The molecular mechanisms underlying these observations are unknown. Objective The objective of this study was to determine the impact of dietary β-carotene and the activity of β-carotene oxygenase 1 (BCO1), which is the enzyme responsible for the conversion of β-carotene to vitamin A, on circulating cholesterol concentration. Methods In our preclinical study, we compared the effects of a 10-d intervention with a diet containing 50 mg/kg of β-carotene on plasma cholesterol in 5-wk-old male and female C57 Black 6 wild-type and congenic BCO1-deficient mice. In our clinical study, we aimed to determine whether 5 common small nucleotide polymorphisms located in the BCO1 locus affected serum cholesterol concentrations in a population of young Mexican adults from the Universities of San Luis Potosí and Illinois: A Multidisciplinary Investigation on Genetics, Obesity, and Social-Environment (UP AMIGOS) cohort. Results Upon β-carotene feeding, Bco1−/− mice accumulated >20-fold greater plasma β-carotene and had ∼30 mg/dL increased circulating total cholesterol (P < 0.01) and non–HDL cholesterol (P < 0.01) than wild-type congenic mice. Our results in the UP AMIGOS cohort show that the rs6564851 allele of BCO1, which has been linked to BCO1 enzymatic activity, was associated with a reduction in 10 mg/dL total cholesterol concentrations (P = 0.009) when adjusted for vitamin A and carotenoid intakes. Non–HDL-cholesterol concentration was also reduced by 10 mg/dL when the data were adjusted for vitamin A and total carotenoid intakes (P = 0.002), or vitamin A and β-carotene intakes (P = 0.002). Conclusions Overall, our results in mice and young adults show that BCO1 activity impacts circulating cholesterol concentration, linking vitamin A formation with the risk of developing ASCVD.


2020 ◽  
Author(s):  
Valeria Sutti Nunes ◽  
Angela Oliveira Godoy Ilha ◽  
Guilherme Silva Ferreira ◽  
Renata Paula Assis Bombo ◽  
Milessa Silva Afonso ◽  
...  

Abstract Background Because the plasma campesterol/cholesterol ratio does not differ between groups that absorb different amounts of cholesterol measured by the gold standard isotopic procedure we investigated whether the intestinal absorption of phytosterols (PS) depends on the body's cholesterol synthesis rate. Methods 38 volunteers (58 ± 12 years; low-density lipoprotein cholesterol (LDL-C) ≥ 130 mg/dL) were randomly assigned to consume 400 mL/day of soy milk or soy milk + PS (1.6 g/day) for 4 weeks in a double-blind, placebo-controlled, cross-over study. Blood samples were collected and markers of phytosterol (PS) absorption and non-cholesterol sterol synthesis precursors measured. Results PS treatment reduced plasma total cholesterol concentration (-5,5%, p < 0.001), LDL-C (-7.6%, p < 0.001), triglycerides (-13.6%, p < 0.0085), and apolipoprotein B (apo B) (-6.3%, p < 0.008), without changing high density lipoprotein cholesterol (HDL-C concentration). The lathosterol-to-cholesterol ratio in serum predicted the serum cholesterol response to PS feeding where high basal cholesterol synthesis was associated with lack of response of plasma cholesterol to PS in the diet. Cholesterol synthesis being elevated in the placebo phase in non-responders to dietary PS indicated they were resistant to further synthesis rise, whereas responders, because they have lower synthesis rate than non-responders in the placebo phase, are capable expanding synthesis under the effect of alimentary PS. Conclusions responders absorbed more PS than non-responders likely resulting from responders delivering less endogenous cholesterol than non-responders into the intestinal lumen that facilitates greater absorption of PS by the intestine.


PEDIATRICS ◽  
1989 ◽  
Vol 84 (6) ◽  
pp. 969-976
Author(s):  
Ken Resnicow ◽  
Jane Morley-kotchen ◽  
Ernst Wynder

Medical and public health recommendations regarding detection and treatment of hyperlipidemia in children have generally been based on two principal epidemiologic studies: the Lipids Research Clinics Population Study (1972 to 1976) and the Bogalusa Heart Study (1973 to 1974). The present study was initiated to further describe the distribution of plasma cholesterol levels in a multiracial sample of American children. Between 1984 and 1988, the total cholesterol levels of 6585 children from 22 schools were measured as part of the Know Your Body School Health Program. For the entire population, ages 5 to 18 years, the mean total cholesterol concentration was 166.4 mg/dL. Total cholesterol was significantly greater in girls (168 mg/dL) than in boys (165 mg/dL), although sex differences were inconsistent across race/ethnicity. The mean value for blacks, 173 mg/dL, and Hispanics, 168 mg/dL, was higher than for Asians, 165 mg/dL, and whites, 163 mg/dL. Across race/ethnicity, values tended to peak between ages 8 and 10 years for girls and approximately 10 years of age for boys. These values are slightly higher than those reported in the Lipids Research Clinics and Bogalusa studies. Public health implications of these findings are discussed.


1979 ◽  
Vol 57 (12) ◽  
pp. 1381-1387 ◽  
Author(s):  
Yung-Sheng Huang ◽  
Suzanne Lussier-Cacan ◽  
Maurice Bidallier ◽  
Liang-Huei Tsay ◽  
Marcel J. Rheault ◽  
...  

Plasma cholesterol turnover was studied in sham-operated and portacaval-shunted miniature swine following an intravenous injection of labeled cholesterol. The specific radioactivity – time curves for periods of 6–7 weeks and 11–13 weeks were analyzed in both groups by a digital computer according to a two-pool and a three-pool model. In this study, the three-pool model generally provided a better fit to the observed data than did the two-pool model. The half-lives of the first and second exponents were significantly decreased in the shunted animals, indicating an elevated turnover of cholesterol. It is suggested that increased hepatic degradation of cholesterol was responsible for the hypocholesterolemic effect of the shunt in our study.


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