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Atherosclerosis
Published in George Feuer, Felix A. de la Iglesia, Molecular Biochemistry of Human Disease, 2020
George Feuer, Felix A. de la Iglesia
Lecithin:cholesterol acyl transferase (LCAT) is an extracellular enzyme produced in the liver which circulates in plasma and acts on HDL. LCAT converts lecithin and unesterified cholesterol to HDL cholesteryl ester and indirectly affects the composition of other plasma lipoproteins and plasma membranes. LCAT promotes the nonenzymatic transfer of lecithin and free cholesterol chylomicron residues and plasma membranes to HDL and the transfer of cholesterol ester from HDL to VLDL and LDL. These reactions control the levels of lecithin and free cholesterol in plasma lipoproteins and facilitate the removal of cholesterol from plasma. LCAT also plays a role in cholesterol transport within the arterial wall, removing cholesterol from arteries and other tissues.177 Furthermore, the reaction catalyzed by LCAT represents the major source of LDL cholesteryl esters and therefore probably takes part in the deposition of extracellular lipids in fibrous plaques.225
Magnesium and dyslipidemia
Published in Kupetsky A. Erine, Magnesium, 2019
Fernando Guerrero-Romero, Martha Rodríguez-Morán
Magnesium, the most abundant intracellular divalent cation15, 16 and the second-most abundant intracellular cation,17 is an essential co-factor in the enzymatic process of high-energy phosphate production,18, 19 the synthesis of nucleic acids and proteins, cytoskeletal function, cell cycle progression, the maintenance of membrane integrity and stability, ion homeostasis,20 and glucose-related metabolic pathways.21, 22 The anti-atherogenic effects of magnesium appear to involve the modification of several enzymes intricately linked with lipid metabolism, inhibiting the activity of lecithin cholesterol acyl transferase (LCAT) and HMG-CoA reductase, and stimulating the activity of lipoprotein lipase.23 Magnesium is necessary for activity of LCAT, which lowers LDL-C and triglyceride levels and raises HDL-C levels; it has been reported that rodents fed magnesium-deficient diets have higher serum triglyceride levels and reduced HDL-c secondary to the reduction of serum activity of LCAT.24 LCAT is also involved in reverse cholesterol uptake, facilitating cholesterol uptake from tissues into HDL-c.25 Experimental studies conducted in rats show that severe magnesium deficiency produces marked changes in the fatty acid pattern of total plasma lipids.26 Furthermore, the enzyme that deactivates HMG-CoA reductase requires magnesium; in vitro studies show that increasing the content of magnesium in bathing solution attenuates HMG-CoA reductase activity.27
Influence of phosphatidylcholine on the activity of SHMT in hypercholesterolemic rats
Published in Robert Hofstra, Noriyuki Koibuchi, Suthat Fucharoen, Advances in Biomolecular Medicine, 2017
A. Dahlan, H. Heryaman, J.B. Dewanto, F.A. Damara, F. Harianja, N. Sutadipura
LCAT plays a role in the esterification of HDL-cholesterol, and phosphatidylcholine acts as the source of fatty acids in the process. Cholesterol ester is transported to the liver to be metabolized into bile acid. So, the phosphatidylcholine acts on LCAT, ACAT, and cholesterol ester hydrolase to control the plasma cholesterol level.
Compared to an Oatmeal Breakfast, Two Eggs/Day Increased Plasma Carotenoids and Choline without Increasing Trimethyl Amine N-Oxide Concentrations
Published in Journal of the American College of Nutrition, 2018
Amanda Missimer, Maria Luz Fernandez, Diana M. DiMarco, Gregory H. Norris, Christopher N. Blesso, Ana Gabriela Murillo, Marcela Vergara-Jimenez, Bruno S. Lemos, Isabel Medina-Vera, Olga V. Malysheva, Marie A. Caudill
The activity of the enzyme LCAT, which is responsible for the esterification of cholesterol, was unchanged between breakfast treatments. In another study in which participants were fed a dose-dependent increase of eggs (1–23) for 4 weeks each, an increase in LCAT activity was found following the consumption of 3 eggs (31). This finding suggests that the consumption of dietary cholesterol from 2 eggs may not have an impact on increasing the function of the enzyme in a healthy population. In an egg feeding study in which 3 eggs were consumed in a population with metabolic syndrome, LCAT activity was increased. Authors connect LCAT activity to an increase in HDL particle size and number, because more dietary cholesterol is being esterified and RCT is enhanced (23). LCAT may also be more active in individuals classified as hyperresponders to dietary cholesterol. In a study in which individuals consumed 3 eggs per day, hyperresponders, regardless of gender, had higher activity of LCAT, in accordance with increased RCT (40).
A novel pathogenic variant in LCAT causing FLD. A case report
Published in Acta Clinica Belgica, 2022
Nuria Goñi Ros, Ricardo González-Tarancón, Paula Sienes Bailo, Elvira Salvador-Ruperez, Martín Puzo Bayod, José Puzo Foncillas
He also showed hypertension, hyperuricemia, chronic kidney disease (CKD) (stage 5) and an altered lipid profile (hypertriglyceridemia (330 mg/dL) and low HDL cholesterol (13 mg/dL)). Low HDL cholesterol is the most remarkable lipid trait both in mild-to-moderate CKD patients as well as in advanced renal disease stages, and it has been previously shown that LCAT concentration is a major determinant of the low HDL phenotype. Specifically, unesterified cholesterol level is the main biochemical accountant for renal disease progression [9]. LCAT deficiency carries the accumulation, in different organs, of phospholipids and unesterified cholesterol [10]. Kidney disease is the major cause of morbidity in patients with complete LCAT deficiency. Hypertension and progressive deterioration of renal function leading to end-stage of renal disease are frequent among patients suffering from FLD and need renal replacement therapy [11]. Developmental mechanisms of renal lesions are not clearly understood, but some authors like Lynn et al. [12] have suggested the role of an abnormal lipoprotein-X (LpX), usually absent in physiological conditions and mainly made of phospholipids and unesterified cholesterol; in the stimulation of monocytes infiltration. Monocytes could contribute to the glomerulosclerosis and renal insufficiency by the presence of foamy cells, producers of cytokines and growth factors. In addition, nephrotic syndrome can itself reduce LCAT activity due to the urinary loss. Appearance and progression of renal failure is variable among FLD cases, and it is likely related to the biochemical phenotype rather than to the inherited mutation [13]. All this highlights the interest of renal biopsy in the diagnosis of LCAT deficiency [14], being electron microscopy the key in this process as lipid deposits appear as irregular small grains, dense to electrons [15].
Assessment of Antihyperlipidemic and Antitumor Effect of Isolated Active Phytoconstituents from Apium graveolens L. through Bioassay-Guided Procedures
Published in Journal of Dietary Supplements, 2019
Research on herbal medicines is gaining ground and the demand to use natural products in the treatment of various disorders is increasing worldwide. Investigations on herbal products might lead to the development of alternative drugs and strategies. Such alternative strategies are required for the effective management of hyperlipidemic disorders. Triton WR 1339 acts as a surfactant and suppresses the action of lipases to block the uptake of lipoproteins from circulation by extrahepatic tissues, resulting in increased blood lipid concentration. The possible mechanism of activity may be due to enhancement of the activity of lecithin acyl transferase (LCAT) and inhibition of the action of hepatic TG lipase on HDL (Patil & Dixit, 2004). LCAT plays a key role in the incorporation of free cholesterol into HDL and transferring it back to VLDL and LDL, which are taken back later in liver cells (Ghule et al., 2006). It is well known that LDL plays an important role in arteriosclerosis and that hypercholesterolemia is associated with a defect relating to the lack of LDL receptors. The decrease of cholesterol and LDL levels achieved by administration of test samples demonstrates a possible protection against hypercholesterolemia and the harm this condition causes. It is also known that HDL cholesterol levels have a protective role in coronary artery disease. Similarly, an increased level of serum LDL cholesterol results in increased risk for the development of atherosclerosis. The increased level of HDL cholesterol and decreased total cholesterol level along with its LDL fraction that is evident from the results could be due to increased cholesterol excretion and decreased cholesterol absorption through the gastrointestinal tract. Thus, the decreasing cholesterol levels in the body under the influence of A. graveolens could have enhanced the enzymatic activity by a positive feedback mechanism.