Study of the Distribution of the Apolipoproteins A-I and A-II, Among Lipoprotein Subclasses in Plasma of Normo- and Hyperlipidemic Subjects

Authors: Odeh MA*, Nima Ebadat and Atmeh RF†

Volume 1, Issue 1

Abstract

Depending on epidemiological study, high density lipoprotein Cholesterol (HDL-C) was considered as a negative risk factor for Coronary artery disease (CAD). However, this inverse relationship is not proved in individual subjects, where there are individuals with high HDL-C but suffer from CAD, and others with low HDL-C but do not have CAD. Moreover, this inverse relationship is now questionable. HDL is a heterogeneous complex of particles that differ in the size, chemical composition, and function, where some of them may have a role in the protection from atherosclerosis; therefore, deeper understanding of the identification and quantitation of its subclasses is badly needed. Here we use an improved immunoblotting method that can directly detect and qauntitate discrete Lipoprotein subclass containing apoA-I (AI-Lp) and Lp subclass containing apoA-II (AII-Lp) subclasses from fresh plasma of normo- and hyperlipidemic subjects. Fresh plasma sample from 167 of normo- and hyperlipidemic males and females were analyzed. At least thirteen AI-Lp subclasses were detected with relative molecular mass ranging from 42,000 to >354,000, these subclasses were given the numbers 1- 13. Seventeen AII-Lp subclasses were detected with relative molecular mass from 50,000 to 900,000; these subclasses were given the roman numbers I-XVII. The smallest subclasses (42,000– 50,000) were not detected in all normoglycemic-normolipidemic subjects. A Large significant increase (P<0.05) in subclass 4 (70,000) was noticed in hypercholesterolimic subjects. AII-Lp subclass IV (105,000-150,000) in hyperlipidemic subjects were significantly correlated with plasma total apo-AI (r=0.32, P<0.05) and total apoA-II (r = 0.72, P<0.01), and a similar correlation was also seen in the normoglycemic group (r = 0.34, P<0.01; r = 0.71, P<0.01, respectively). This may indicate that the function of this main AII-Lp subclass is impaired in different pathologies, and this is more significant than its plasma level. The immunoblotting method used is the method of choice, at present, to study the quantitative distribution of AI-Lp and AII-Lp subclasses in fresh plasma because it’s superior to the other method available in terms of the quantitative aspects and its performance.

Keywords: Apolipoproteins; Normoglycemic-Normolipidemic; Immunoblotting; Apolipoprotein

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