Lipoprotein metabolism

2011 ◽  
pp. 1659-1667 ◽  
Author(s):  
Bo Angelin ◽  
Paolo Parini
Keyword(s):  
Fatty Acids ◽  
Lipid Metabolism ◽  
Plasma Lipids ◽  
Plasma Lipid ◽  
Lipoprotein Metabolism ◽  
Protective Role ◽  
Plasma Lipoprotein ◽  
Major Function ◽  
Signalling Molecules ◽  
Genetic And Environmental Factors

The realization that raised concentrations of plasma lipids, particularly cholesterol, are associated with an increased risk of coronary heart disease has stimulated the study of factors regulating plasma lipid metabolism. With the use of increasingly refined methodology, our understanding of normal plasma lipoprotein metabolism and its derangements due to the influence of genetic and environmental factors is continuously expanding. This chapter summarizes some current concepts regarding plasma lipoprotein transport in normal humans, forming a basis for the discussion of the development of various dyslipidaemias in the following chapters. Lipids represent a heterogeneous group of substances with several biological functions. Phospholipids and cholesterol are essential components of cell membranes, and cholesterol is also the precursor of steroid hormones and bile acids. Some fatty acids form the origin of bioactive compounds such as prostaglandins, thromboxanes, and leukotrienes; phospholipids, fatty acids, and cholesterol may also serve as signalling molecules in their own right. Furthermore, lipid complexes are necessary for the transport of lipid-soluble vitamins, and may have a protective role in the defence against toxins and infectious agents. From an overall physiological perspective, however, the major function of plasma lipid metabolism is the exchange of fat as energy substrates.

scholarly journals Modulation of hepatic apolipoprotein B, 3-hydroxy-3-methylglutaryl-CoA reductase and low-density lipoprotein receptor mRNA and plasma lipoprotein concentrations by defined dietary fats. Comparison of trimyristin, tripalmitin, tristearin and triolein

1995 ◽  
Vol 311 (1) ◽  
pp. 167-173 ◽  
Author(s):  
A J Bennett ◽  
M A Billett ◽  
A M Salter ◽  
E H Mangiapane ◽  
J S Bruce ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Plasma Lipids ◽  
Low Density Lipoprotein ◽  
Lipoprotein Metabolism ◽  
Density Lipoprotein ◽  
Dietary Fats ◽  
Low Density ◽  
Mrna Levels ◽  
Expression Of Genes ◽  
Coa Reductase

Different dietary fatty acids exert specific effects on plasma lipids but the mechanism by which this occurs is unknown. Hamsters were fed on low-cholesterol diets containing triacylglycerols enriched in specific saturated fatty acids, and effects on plasma lipids and the expression of genes involved in hepatic lipoprotein metabolism were measured. Trimyristin and tripalmitin caused significant rises in low-density lipoprotein (LDL) cholesterol which were accompanied by significant reductions in hepatic LDL receptor mRNA levels. Tripalmitin also increased hepatic expression of the apolipoprotein B gene, implying an increased production of LDL via very-low-density lipoprotein (VLDL) and decreased removal of LDL in animals fed this fat. Hepatic levels of 3-hydroxy-3-methylglutaryl-CoA reductase mRNA did not vary significantly between the groups. Compared with triolein, tristearin had little effect on hepatic gene expression or total plasma cholesterol. However, it caused a marked decrease in VLDL cholesterol and a rise in LDL cholesterol such that overall it appeared to be neutral. Lipid analysis suggested a rapid desaturation of much of the dietary stearate. The differential changes in plasma lipids and hepatic mRNA levels induced by specific dietary fats suggests a role for fatty acids or a metabolite thereof in the regulation of the expression of genes involved in lipoprotein metabolism.

Role of plasma lipids in transport of fatty acids for butterfat formation

1960 ◽  
Vol 198 (1) ◽  
pp. 45-47 ◽  
Author(s):  
P. M. Riis ◽  
Jack R. Luick ◽  
Max Kleiber
Keyword(s):  
Fatty Acids ◽  
Plasma Proteins ◽  
Turnover Rate ◽  
Plasma Lipids ◽  
Specific Activity ◽  
Plasma Lipid ◽  
Half Time

Cow plasma containing P32- and C14-labeled lipids and proteins was infused into a lactating cow. The specific activity of the lipids and volatile acids of the plasma and of the expired CO2 and milk constituents was determined. The turnover rate of phospholipid P and of plasma lipid volatile acids was 0.1 hours–1, this means a half-time of 7 hours. Little radioactivity was found in the expired CO2 and none was found in plasma volatile acids. These findings and the distribution of C14 in milk constituents indicate that plasma proteins do not contribute carbon to butterfat and that the catabolism of plasma lipids and proteins does not lead to a significant formation of nonlipid butterfat precursors. These observations permit a further calculation which indicates that 50% of the butterfat C originates from plasma lipid C.

scholarly journals ILRUN , a Human Plasma Lipid GWAS Locus, Regulates Lipoprotein Metabolism in Mice

2020 ◽  
Vol 127 (11) ◽  
pp. 1347-1361 ◽  
Author(s):  
Xin Bi ◽  
Takashi Kuwano ◽  
Paul C. Lee ◽  
John S. Millar ◽  
Li Li ◽  
...  
Keyword(s):  
Plasma Lipids ◽  
Plasma Cholesterol ◽  
Plasma Lipid ◽  
Lipoprotein Metabolism ◽  
Peroxisome Proliferator ◽  
Nucleotide Polymorphisms ◽  
Genetic Associations ◽  
Peroxisome Proliferator Activated Receptor ◽  
Liver Transcriptome ◽  
Artery Disease

Rationale: Single-nucleotide polymorphisms near the ILRUN (inflammation and lipid regulator with ubiquitin-associated–like and NBR1 [next to BRCA1 gene 1 protein]-like domains) gene are genome-wide significantly associated with plasma lipid traits and coronary artery disease (CAD), but the biological basis of this association is unknown. Objective: To investigate the role of ILRUN in plasma lipid and lipoprotein metabolism. Methods and Results: ILRUN encodes a protein that contains a ubiquitin-associated–like domain, suggesting that it may interact with ubiquitinylated proteins. We generated mice globally deficient for Ilrun and found they had significantly lower plasma cholesterol levels resulting from reduced liver lipoprotein production. Liver transcriptome analysis uncovered altered transcription of genes downstream of lipid-related transcription factors, particularly PPARα (peroxisome proliferator-activated receptor alpha), and livers from Ilrun -deficient mice had increased PPARα protein. Human ILRUN was shown to bind to ubiquitinylated proteins including PPARα, and the ubiquitin-associated–like domain of ILRUN was found to be required for its interaction with PPARα. Conclusions: These findings establish ILRUN as a novel regulator of lipid metabolism that promotes hepatic lipoprotein production. Our results also provide functional evidence that ILRUN may be the casual gene underlying the observed genetic associations with plasma lipids at 6p21 in human.

scholarly journals Diets deficient in selenium and vitamin E affect plasma lipoprotein and apolipoprotein concentrations in the rat

1996 ◽  
Vol 76 (6) ◽  
pp. 899-907 ◽  
Author(s):  
A Mazur ◽  
F Nassir ◽  
E Gueux ◽  
C Moundras ◽  
J Bellanger ◽  
...  
Keyword(s):  
Vitamin E ◽  
Plasma Cholesterol ◽  
Plasma Lipid ◽  
Lipoprotein Metabolism ◽  
Plasma Lipoprotein ◽  
Vitamin E Deficiency ◽  
Apo B ◽  
Apo E ◽  
Se Deficiency

The present study examined the effects of Se, vitamin E and combined Se and vitamin E deficiencies in rats on plasma lipid, Lipoprotein and apolipoprotein (apo) concentrations. Deficiencies were induced by feeding rats the respective diets for 6 weeks. The study shows that Se deficiency results in increased concentrations of plasma cholesterol and apo E. Both could be explained by an increase in the HDL1 fraction. Vitamin E deficiency alone had no significant effect on plasma lipid, lipoprotein and apo concentrations. Se deficiency in combination with vitamin E deficiency leads to an increase in plasma LDL and apo B concentrations. These results point to the need for further investigations on the mechanism by which Se deficiency affects lipoprotein metabolism.

Genetic variations at the lipoprotein lipase gene influence plasma lipid concentrations and interact with plasma n-6 polyunsaturated fatty acids to modulate lipid metabolism

2011 ◽  
Vol 218 (2) ◽  
pp. 416-422 ◽  
Author(s):  
Antonio Garcia-Rios ◽  
Javier Delgado-Lista ◽  
Pablo Perez-Martinez ◽  
Catherine M. Phillips ◽  
Jane F. Ferguson ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Lipid Metabolism ◽  
Polyunsaturated Fatty Acids ◽  
Lipoprotein Lipase ◽  
Plasma Lipid ◽  
Genetic Variations ◽  
Lipase Gene ◽  
Lipoprotein Lipase Gene

Implication of lipids in macrosomia of diabetic pregnancy: can n-3 polyunsaturated fatty acids exert beneficial effects?

2003 ◽  
Vol 105 (5) ◽  
pp. 519-529 ◽  
Author(s):  
Hafida MERZOUK ◽  
Naim A. KHAN
Keyword(s):  
Fatty Acids ◽  
Lipid Metabolism ◽  
Polyunsaturated Fatty Acids ◽  
Plasma Lipids ◽  
Diabetic Pregnancy ◽  
Infants Of Diabetic Mothers ◽  
Beneficial Effects ◽  
Obesity And Diabetes ◽  
Diabetic Mothers

Macrosomia or fetal obesity is a frequent complication of pregnancy in diabetes mellitus. Several alterations observed in carbohydrate and lipid metabolism in macrosomic infants of diabetic mothers are thought to be a consequence of maternal hyperglycaemia leading to fetal hyperinsulinaemia. Macrosomic infants of diabetic mothers are prone to the development of glucose intolerance, obesity and diabetes during childhood and adulthood. Furthermore, increasing evidence is accumulating regarding the importance of n-3 polyunsaturated fatty acids (PUFAs) in the reduction of plasma lipids and hyperglycaemia. In this review article, we shed light on the abnormalities in lipid metabolism in macrosomia. We also raise the question of the possible beneficial effects of n-3 PUFAs in diabetic pregnancy and in the prevention and treatment of long-term metabolic abnormalities associated with macrosomia.

scholarly journals IMPACT OF TUBERCULOSIS AND ANTITUBERCULOUS CHEMOTHERAPY ON LIPID COMPOSITION OF THE BLOOD PLASMA

2018 ◽  
Vol 23 (5) ◽  
pp. 220-224
Author(s):  
Dmitri Sergeevich Riasensii ◽  
N. A. Grishkina ◽  
A. V. Aseev
Keyword(s):  
Lipid Metabolism ◽  
Pulmonary Tuberculosis ◽  
Blood Plasma ◽  
Plasma Lipids ◽  
Phospholipid Composition ◽  
Plasma Lipid ◽  
Aged Patients ◽  
Intensive Phase ◽  
Lipid Spectrum ◽  
Antituberculous Chemotherapy

Tuberculosis is an infectious disease caused by tuberculosis mycobacteria of human or bovine types and is characterized by multiple organs failure and chronic recurrent course. The blood plasma lipid spectrum state is one of the antituberculous chemotherapy toxic effect markers. The important role of the ratio of various fractions of general and blood phospholipids for the evaluation of the state of the organism in infectious pathology is proved. The purpose of this work is to study the features of the lipid spectrum of blood plasma in patients with pulmonary tuberculosis prior to treatment and at the end of the intensive phase of antituberculous chemotherapy. Three hundred and eight young and middle-aged patients with pulmonary tuberculosis were examined. The lipid and phospholipid spectrum of blood was determined prior to initiating the antituberculous chemotherapy and after the end of the intensive phase. The absolute content of general lipids and total phospholipids of blood plasma, as well as all their fractions, in patients with pulmonary tuberculosis were higher than in healthy volunteers. In this regard, the representation of the lipid spectrum in absolute units does not reflect all the features of lipid metabolism disruption, which is primarily manifested in the plasma lipids main classes ratio violation. It is shown that the spectrum of lipid and phospholipid composition of blood plasma in patients with pulmonary tuberculosis differs significantly from the spectrum in healthy people. Antituberculous chemotherapy with bactericidal and bacteriostatic action comes with normalization of a number of lipid metabolism indicators such as free fatty acids, triglycerides, cholesterol esters and phosphatidylserine. However, such indicators as total phospholipids, free cholesterol and lysophospholipids show negative dynamics, which is probably caused by the antituberculous drug’s effect.

Lipids as Triggering Factors in Thrombosis

1976 ◽  
Vol 35 (01) ◽  
pp. 032-048 ◽  
Author(s):  
Arne Nordøy
Keyword(s):  
Lipid Metabolism ◽  
Dietary Habits ◽  
Plasma Lipids ◽  
Experimental Studies ◽  
Plasma Lipid ◽  
High Ratio ◽  
The Body ◽  
Dietary Fats ◽  
Western World ◽  
Platelet Factor

SummaryAn association has been established between acute and more persistent changes in lipid metabolism as reflected in plasma lipids, and platelet lipid metabolism. Platelet function is affected, particularly the activity and availability of platelet factor 3, however, also other changes making the platelets more sensitive to aggregating substances without interfering with the lipid part of platelet factor 3, have been documented. Experimental studies have demonstrated an increased tendency to thrombosis in animals given a diet with a high fat content with a high ratio of saturated to polyunsaturated fatty acids. Studies in man have mainly established a connection between dietary fats, plasma lipid abnormalities and frequency of coronary heart disease and clinical studies more directly relating thrombosis to lipid metabolism is highly warranted. Many open questions remain to be answered. Probably most relevant would be to understand how the antithrombotic mechanisms in the body are affected by changes in lipid metabolism. Even if thrombotic lesions are very common events in the western world our knowledge based on laboratory and experimental studies should indicate a much higher incidence, solely based on interactions between lipids and platelets in subjects exposed to our dietary habits and our way of life.

Abstract 128: Short-Term, High-Saturated and Trans Fatty Acid Diet Increases Expression of Key Intestinal Genes Involved in Lipoprotein Metabolism in Healthy Males

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
André J Tremblay ◽  
Benoit Lamarche ◽  
Valerie Guay ◽  
Valery Lemelin ◽  
Patrick Couture
Keyword(s):  
Fatty Acids ◽  
Apolipoprotein B ◽  
High Fat Diet ◽  
Plasma Lipid ◽  
Lipoprotein Metabolism ◽  
High Fat ◽  
Low Fat ◽  
Short Term ◽  
Low Fat Diet ◽  
Key Genes

Dietary saturated fat (SFA) and trans fatty acids (TFA) have been linked to an increased risk of cardiovascular disease mainly by increasing plasma LDL-C levels. The modulation of cholesterol and fatty acids homeostasis by SFA and TFA is thought to be mediated by changes in expression of key intestinal genes involved in lipid and lipoprotein metabolism. However, the short-term impact of dietary fat intake on expression of these genes has not been fully investigated. To test whether short-term changes in SFA and TFA intake affects expression of key intestinal genes involved in lipid and lipoprotein metabolism, we conducted a randomized, double-blind, cross-over study using an intensive dietary modification in 12 nonobese healthy men with normal plasma lipid profile. Participants were subjected to 2 isocaloric 3-day diets: 1) high-fat diet (37% energy from fat, 15% from SFA, 3.5% from TFA and 50% energy from carbohydrate) and 2) low-fat diet (25% energy from fat, 6% from SFA, 0% from TFA and 62% energy from carbohydrate) in random order, each separated by a two-week washout period. Fasting plasma lipid levels were determined and expression of key genes involved in lipid and lipoprotein metabolism was compared by real-time PCR quantification in duodenal biopsy specimens obtained in the fasted state after 3 days of feeding on each diet. Following the 3-day high-fat diet, plasma-C (+7.4%, P=0.02), LDL-C (+16.9%, P=0.005) and HDL-C (+9.3%, P=0.002) levels were significantly increased as compared to low-fat diet. Plasma triglycerides (-31.7%, P=0.001) and apolipoprotein B-48 (-39.6%, P=0.003) levels were significantly decreased after the high-fat diet relative to the low-fat diet. The high-fat diet also resulted in significant increases in intestinal mRNA expression levels of SREBP-2, HNF-4α, PPAR-α, PPAR-γ, NPC1L1, ABCG8, FABP-2, ACAC-α, SCD-1, ELOVL5, DGAT-2, apolipoprotein B, MTTP, SAR1β and LDL receptor. These findings suggest that short-term exposure to a high-SFA and TFA diet upregulates the expression of key genes involved in lipid and lipoprotein metabolism at the enterocyte level.

scholarly journals Sex Differences in Lipid and Lipoprotein Metabolism: It's Not Just about Sex Hormones

Endocrinology ◽  
2011 ◽  
Vol 152 (3) ◽  
pp. 1192-1192
Author(s):  
Xuewen Wang ◽  
Faidon Magkos ◽  
Bettina Mittendorfer
Keyword(s):  
Sex Differences ◽  
Sex Hormones ◽  
Plasma Lipids ◽  
Plasma Lipid ◽  
Lipoprotein Metabolism ◽  
Men And Women ◽  
Beneficial Effects ◽  
Physiological Alterations ◽  
First Pass ◽  
Hormonal Milieu

Abstract It is commonly thought that sex hormones are important regulators of plasma lipid kinetics and are responsible for sexual dimorphism in the plasma lipid profile. Here we discuss the findings from studies evaluating lipid and lipoprotein kinetics in men and women in the context of what we know about the effects of exogenous sex hormone administration, and we conclude that it is more complicated than that. It has become clear that normal physiological alterations in the hormonal milieu (i.e. due to menopause or throughout the menstrual cycle) do not significantly affect plasma lipid homeostasis. Furthermore, parenterally administered estrogens have either no effect or only very small beneficial effects, whereas orally administered estrogens raise plasma triglyceride concentrations—a phenomenon that is not consistent with the observed sex differences and likely results from the hepatic “first-pass effect.” The effects of progestogens and androgens mimic only in part the differences in plasma lipids between men and women. Thus, the underlying physiological modulators of plasma lipid metabolism responsible for the differences between men and women remain to be elucidated.

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