Abstract
The present study aimed at investigating physicochemical changes in modified LDL by sugars specifically fructose due to recent reports on its involvement in cardiovascular diseases and also glucose and their role in subsequent in vitro accumulation of cholesterol in macrophages. Antiglycation action of aminoguanidine was also investigated. LDL isolated from human blood was incubated with fructose or glucose and aminoguanidine where indicated. The physicochemical changes in modified LDL were detected by electrophoretic, spectroscopic and chemical analysis. Accumulation of cholesterol and its inhibiton in human monocyte-derived macrophages incubated with modified LDL was determined by HPLC. Results showed increased relative electrophoretic mobility, hyperchromicity at 280 nm, development of AGE fluorescence, decrease in free amino groups and increased carbonyl content in glycated LDL as compared to native LDL. Also total cholesterol accumulated in macrophages was more for glycated LDL as compared to native LDL. The magnitude of changes was more prominent in case of fructose as compared to glucose. Aminoguanidine showed remarkable restriction of glycation-induced alterations in LDL and also in accumulation of cholesterol in macrophages. The study thus proclaims that LDL-AGEs formed by fructose may contribute to accelerated initiation of diabetes induced atherosclerosis via foam cells generation and aminoguanidine may have therapeutic potential against it.
Highlights
Non-enzymatic glycation involves a complex series of sequential reactions between reducing sugars and nucleophilic groups of various biomolecules like proteins, lipids and nucleic acids, giving rise to fluorescent and/or colored adducts known as Advanced glycated end-products (AGEs) [1]
All the chemicals used during the study like D-glucose, D-fructose, AG, Diethyleneaminepenta acetic acid (DETAPAC), Trinitrobenzene sulphonic acid (TNBS), DNPH as well as salts for Phosphate buffer saline (PBS) were procured from Sigma Aldrich (St Louis MO, USA)
Incubation of Low density lipoprotein (LDL) with 25 mM glucose or fructose resulted in a significant increase in relative electrophoretic mobility (REM) and indicative of an overall decrease in positive charge (Table 1)
Summary
Non-enzymatic glycation involves a complex series of sequential reactions between reducing sugars and nucleophilic groups of various biomolecules like proteins, lipids and nucleic acids, giving rise to fluorescent and/or colored adducts known as AGEs [1]. AGEs, which are termed as glycotoxins, are well-known triggers of excess reactive oxygen species and abnormally high oxidative stress They have been shown to accumulate in the circulation and in various tissues with normal process of ageing [2] and under number of pathological conditions like atherosclerosis [3], osteoarthritis, retinopathy [4] and cancer. LDL is referred to as a prime target for oxidative modifications contributing to different processes that can be considered proatherogenic This has led to the hypothesis of possible role of LDL-AGEs in increasing artherosclerotic risk of patients with diabetes and hypercholesterolemia [11]. Recent evidences on LDL-AGEs as a prime link for diabetes-associated cardiovascular diseases have shifted the focus of glycobiology on studies involving glycation of LDL with different compounds like glucose [15], ribose [16], glycolaldehyde [17], etc. The possible inhibitory effect of AG on physicochemical changes in glycated LDL and on its in vitro accumulation of cholesterol in HMDM will be investigated
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
