News Update on Lipoprotein Research: Feb – 2020

Lipoprotein Lipase

LIPOPROTEIN lipase, a hydrolytic enzyme produced by many tissues, is rate-limiting for the removal of lipoprotein triglycerides from the circulation. It also has distinct roles in many normal tissues, also as a crucial role in certain metabolic diseases, including obesity. quite 40 years ago, Hahn noticed that intravenous heparin totally cleared diet-induced lipemia in dogs.1 The addition of heparin to plasma in vitro didn’t reproduce this effect, suggesting that the causative agent was released into plasma by heparin in vivo . This factor, ultimately identified as a triglyceride lipase, was activated within the presence of high-density lipoproteins (HDLs). [1]

Lipoprotein oxidation and lipoprotein-induced cytotoxicity.

The results of this study indicate that when human VLDL or LDL is ready under conditions allowing oxidation, such oxidation renders the molecular complexes highly toxic to human skin fibroblasts growing in culture. The cytotoxicity are often predicted by assaying for the presence of thiobarbituric acid-reacting substances on the lipoprotein. However, malondialdehyde, which reacts with thiobarbituric acid and is understood to be injurious to cells, wasn’t cytotoxic within the same experimental system when dissolved in medium or covalently sure to non-toxic LDL. The toxic agent(s) on oxidized LDL is(are) located during a lipid-extractable moiety. Since lipid peroxides and oxidized sterols can occur in vivo under various pathological conditions, the cytotoxicity of those lipoprotein-associated substances observed in vitro could also be associated with certain manifestations of those conditions. [2]

The mysteries of lipoprotein (a)

Lipoprotein(a) [Lp(a)] may be a macromolecular complex found in human plasma that mixes structural elements from the lipoprotein and blood coagulation systems which is related to premature coronary heart condition and stroke. it’s assembled from LDL (LDL) and an outsized hydrophilic glycoprotein called apolipoprotein(a) [apo(a)], which is homologous to the protease zymogen plasminogen. Plasma Lp(a) concentrations vary 1000-fold between individuals and represent endless quantitative genetic trait with a skewed distribution in Caucasian populations. Variation within the hypervariable apo(a) gene on chromosome 6q2.6-q2.7 and interaction of apo(a) alleles with defective LDL-receptor genes explain an outsized fraction of the variability of plasma Lp(a) concentrations. Though of high theoretical and practical interest, many aspects of the metabolism, function, evolution, and regulation of plasma concentrations of Lp(a) are presently unknown, controversial, or mysterious. [3]

Maternal preconception lipid profile and gestational lipid changes in relation to birthweight outcomes

In 575 women with 1–2 prior pregnancy losses; total cholesterol, LDL cholesterol (LDL-C), HDL cholesterol (HDL-C), and triglycerides (TG) were evaluated preconception and throughout pregnancy to guage whether previously observed associations between trimester maternal lipid profile and birthweight outcomes are driven by preconception lipids or lipid changes during pregnancy. Lipid trajectories were compared by pre-pregnancy body mass index (BMI). [4]

Effects of Citrus Limon Juice on Serum Bilirubin, High Density Lipoprotein and Low Density Lipoprotein in Adult Male Wistar Rats under Variable Models of Stress

Introduction: There has been sufficient awareness on atherosclerosis but this has not reduced the amount of individuals with it. Atherosclerosis is promoted by rarity lipoprotein (LDL) without sufficient removal of fats and cholesterol by high density lipoprotein (HDL). Stress is linked with hyperlipidemia, lowering HDL and increasing LDL levels. lemon is understood for its rich minerals and flavonoid content which are employed widely.

This study is aimed toward assessing the hypolipidemic effects of lemon on Bilirubin, HDL and LDL levels.

Place and Duration of Study: Department of physiology, Delta State University Abraka. [5]

Reference

[1] Eckel, R.H., 1989. Lipoprotein lipase. New England Journal of Medicine, (Web Link)

[2] Hessler, J.R., Morel, D.W., Lewis, L.J. and Chisolm, G.M., 1983. Lipoprotein oxidation and lipoprotein-induced cytotoxicity. Arteriosclerosis: An Official Journal of the American Heart Association, Inc., (Web Link)

[3] Utermann, G., 1989. The mysteries of lipoprotein (a). Science, (Web Link)

[4] Maternal preconception lipid profile and gestational lipid changes in relation to birthweight outcomes
Alaina M. Bever, Sunni L. Mumford, Enrique F. Schisterman, Lindsey Sjaarda, Neil J. Perkins, Nicole Gerlanc, Elizabeth A. DeVilbiss, Robert M. Silver, Keewan Kim, Carrie J. Nobles, Melissa M. Amyx, Lindsay D. Levine & Katherine L. Grantz
Scientific Reports, (Web Link)

[5] Kenneth Kelechi, A., Melish Elias, D. T., Oberhiri Lawrence, E. and John Chukwuma, O. (2017) “Effects of Citrus Limon Juice on Serum Bilirubin, High Density Lipoprotein and Low Density Lipoprotein in Adult Male Wistar Rats under Variable Models of Stress”, Journal of Advances in Medical and Pharmaceutical Sciences, (Web Link)

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