Lipids in Health and Disease

Background: Apolipoprotein B (apoB) contains ligand-binding domain for the binding of LDL to LDL-R site, which enables the removal of LDL from circulation. Our recent data showed that selenium (Se) is involved in the lipid metabolism. The present study was aimed to understand the effect of Se deficiency (0.02 ppm) and selenium supplementation (1 ppm) on apoB expression in liver during hypercholesterolemia in male Sprague Dawley rats. Animals were fed with control and high cholesterol diet (2%) for 1 and 2 months. ApoB levels by ELISA and protein expression by western blot was done. Hepatic LDL receptor (LDL-R) activity (in vivo) and mRNA expression by RT-PCR was monitored. Results: In selenium deficiency and on high cholesterol diet (HCD) feeding apoB levels increased and LDL-R expression decreased significantly after 2 months. On 1 ppm selenium supplementation apoB expression significantly decreased and LDL-R expression increased after 2 months. But after one month of treatment there was no significant change observed in apoB and LDL-R expression. Conclusion: So the present study demonstrates that Se deficiency leads to up regulation of apoB expression during experimental hypercholesterolemia. Selenium supplementation upto 1 ppm leads to downregulation of apoB expression. Further, this study will highlight the nutritional value of Se supplementation in lipid metabolism. Background The interaction between LDL and LDL receptor has a major role in determining plasma cholesterol levels [1,2] and apolipoprotein B (apoB) has the central role in this ligand-receptor interaction. Mutations in the apoB gene result in accumulation of LDL in circulation [3,4]. However, most of the studies suggested that one molecule of apoB exists per lipoproteinparticle, thus the quantity of apoB in fasting plasma predicts the number of LDL and VLDL particles [5,6]. Therefore, plasma apoB levels maybe a better assay of the concentration of atherogenic lipoproteinparticles than total or LDL cholesterol levels [7]. Furthermore, a cross-sectional study in patients who had coronary arterybypass graft surgery determined that apoB concentration wasa better discriminator than LDL cholesterol concentration inpredicting recurrent atherosclerotic disease in bypass grafts10 years after surgery [8]. Abnormalities in the apoB metabolism are responsible for the generation of hypercholesterolemia and increased risk of coronary heart disease [9]. Homma [10] reported a positive correlation between serum apoB levels and atherosclerotic conditions. Abraham et al. [11] have found a significantly increased production of apoB levels in culPublished: 05 November 2005 Lipids in Health and Disease 2005, 4:28 doi:10.1186/1476-511X-4-28 Received: 17 October 2005 Accepted: 05 November 2005 This article is available from: http://www.lipidworld. com/content/4/1/28 © 2005 Dhingra and Bansal; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.