Nutritional Ergogenic Aids: Introduction, Definitions and Regulatory Issues
Ira Wolinsky, Judy A. Driskell in Nutritional Ergogenic Aids, 2004
Fatty acids that are absorbed lymphatically appear in the bloodstream as chylomicrons within minutes after consuming a fat-containing meal. The primary function of chylomicrons is to deliver dietary fatty acids (in the form of triglycerides) to peripheral tissues for storage or energy utilization. For this delivery to occur, the chylomicrons must interact with the enzyme lipoprotein lipase anchored on the capillary endothelium of various tis-sues.54,55 Lipoprotein lipase converts the triglyceride into free fatty acids and monoglycerides, allowing entry into tissues. Complete hydrolysis of tri-glyceride is limited, although some free glycerol is produced and can escape into the bloodstream. Those tissues expressing the highest concentration of lipoprotein lipase are muscle and adipose,56 indicating that these tissues are quantitatively the most important recipients of dietary fat. Lipoprotein lipase associated with cardiac muscle has a particularly high affinity for chylomi-crons and other triglyceride-rich lipoproteins, thus ensuring an adequate and constant energy supply for the heart.
Mechanisms of action
Fazal-I-Akbar Danish, Ahmed Ehsan Rabbani in Pharmacology in 7 Days for Medical Students, 2018
Fenofibrate is a prodrug. It is converted to an active metabolite ‘fenofibric acid’ which is responsible for the triglyceride-lowering effect of the drug. Fenofibric acid, once formed, attaches to its receptor: peroxisome proliferator-activated receptor-alpha (PPAR-α). The activated receptor then binds to peroxisome proliferator response elements located in various gene promoters. These elements increase the expression of genes encoding for lipoprotein lipase. This enzyme is primarily found on the surface of endothelial cells. Its main function is to clip off free fatty acids from within the lipoprotein complexes so that the same can be taken up into the cells. This leads to depletion of triglycerides (3 × fatty acids + glycerol) from the lipoprotein complexes. Increased expression of lipoprotein lipase means increased clearance of triglyceride-rich lipoproteins from the circulation leading to a fall in triglyceride levels. This also in turn leads to decreased cholesterol biosynthesis in the liver.
Atherosclerosis
George Feuer, Felix A. de la Iglesia in Molecular Biochemistry of Human Disease, 2020
Lipoprotein lipase is present in many tissues; adipose tissue and skeletal muscle constitute major sites. This lipase is primarily responsible for the hydrolysis of plasma lipoprotein triglyceride.351 Lipoprotein lipase differs from other lipases in that it needs apoC-II as a cofactor and is activated by low concentrations of heparin.629 Lipoprotein lipase activity can show wide fluctuations representing an adaptive mechanism whereby plasma triglyceride fatty acids are removed from circulation according to need.465 During postprandial triglyceride storage, the adipose tissue lipase activity is high. When triglycerides are mobilized as in starvation, lipase activity is low. This decrease in enzyme activity on the endothelial surface can result in an increased accumulation of VLDL and chylomicrons in the circulation. There are two pathological conditions connected with reduced lipoprotein lipase activity in adipose tissue: (1) uncontrolled diabetes mellitus317,332,507 and (2) familial hyperchylomicronemia (Type I hyperlipoproteinemia).566 In diabetes mellitus, lipase deficiency of adipose tissue is due to reduced levels of circulating insulin. Following treatment with this hormone, the enzyme activity returns to normal.329,360 There is an interaction between lipoprotein lipase and heparin-like polysaccharides.57
Exendin-4, a glucagon-like peptide-1 receptor agonist downregulates hepatic receptor for advanced glycation end products in non-alcoholic steatohepatitis rat model
Published in Archives of Physiology and Biochemistry, 2018
Mona M. Allam, Walaa B. El gazzar
Hepatic triglycerides were extracted and measured using a commercial kit cat No.110104 based on a colorimetric assay from Jiancheng Bioengineering Institute (Nanjing, China) according to the manufacturer’s instructions. GPO-PAP enzyme method is used to detect levels of TG. First, triglyceride decomposes glycerol and fatty acids with lipoprotein lipase catalysis. Second, the reaction between glycerol and ATP produces glycerophosphoric acid and ADP via glycerol kinase catalysis. After that, glycerophosphoric acid decomposes phosphodihydroxyacetone and H2O2 by glycerol phosphate oxidase. Lastly, H2O2 can react with 4-aminoantipyrine to produce red quinone compound through POD. The production is proportional to the triglyceride content. (Cole et al.2000).
Stink bean (Parkia speciosa) empty pod: a potent natural antidiabetic agent for the prevention of pancreatic and hepatorenal dysfunction in high fat diet/streptozotocin-induced type 2 diabetes in rats
Published in Archives of Physiology and Biochemistry, 2023
Liwei Gao, Wenzhi Zhang, Leiyan Yang, Hong Fan, Opeyemi Joshua Olatunji
One of the main alteration experienced in diabetes is hyperlipidaemia, a condition that predisposes diabetic patient to cardiovascular diseases (Nandini and Naik 2019). Several studies have illustrated the prominent role insulin plays in lipid metabolism by stimulating lipogenesis and increasing the uptake of triglycerides in the blood to the muscles and adipose tissues, thus annihilating lipolysis through the action of lipoprotein lipase enzyme and subsequent reduction in the plasma level of triglycerides and fatty acids (Qaid and Abdelrahman 2016). In diabetes, the action of lipoprotein lipase enzyme is significantly reduced which leads to increase in adipose tissue lipolysis and high levels of triglycerides (Taskinen 1987; Eriksson et al. 2003; Huang et al. 2013). Furthermore, the increase in triglycerides promotes β-oxidation of fatty acids and cholesterol outputs leading to hypercholesterolaemia and hypertriglyceridaemia (Albasher et al. 2020). The results from this study indicated that diabetic rats showed significantly higher levels of triglycerides, total cholesterol, and LDL-C, while HDL was significantly reduced. However, treatment with PPS ameliorated hypercholesterolaemia and hypertriglyceridaemia, suggesting the protective role of PPS in hyperglycaemia-associated dyslipidemia.
Pharmacological treatment options for severe hypertriglyceridemia and familial chylomicronemia syndrome
Published in Expert Review of Clinical Pharmacology, 2018
Rabia Chaudhry, Adie Viljoen, Anthony S. Wierzbicki
Familial chylomicronemia syndrome is an orphan disease associated with extreme hypertriglyceridemia and pancreatitis.A description of the pathophysiology of deficiencies in the lipoprotein lipase pathway is provided.The effectiveness of current treatment options is reviewedData on novel treatments in development for familial chylomicronemia syndrome are summarizedInhibition of apolipoprotein C3 function seems to be the most promising treatment for this disorder.
Related Knowledge Centers
- Chylomicron
- Endothelial Lipase
- Enzyme
- Hydrolysis
- Lipase
- Pancreatic Lipase Family
- Hepatic Lipase
- Triglyceride
- Lipoprotein
- Very Low-Density Lipoprotein