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Mediators of Inflammation
Volume 2014, Article ID 263786, 12 pages
http://dx.doi.org/10.1155/2014/263786
Research Article

Niacin Inhibits Vascular Inflammation via Downregulating Nuclear Transcription Factor-κB Signaling Pathway

1Key Laboratory of Atherosclerosis in Universities of Shandong and Institute of Atherosclerosis, Taishan Medical University, Shandong 271000, China
2College of Basic Medical Sciences, Taishan Medical University, Shandong 271000, China
3Shandong Agricultural University, Shandong 271000, China
4Department of Geriatrics, PLA Navy General Hospital, Beijing 100048, China

Received 9 January 2014; Revised 1 April 2014; Accepted 16 April 2014; Published 27 May 2014

Academic Editor: Clara Di Filippo

Copyright © 2014 Yanhong Si et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The study aimed to investigate the effect of niacin on vascular inflammatory lesions in vivo and in vitro as well as its lipid-regulating mechanism. In vivo study revealed that niacin downregulated the levels of inflammatory factors (IL-6 and TNF-α) in plasma, suppressed protein expression of CD68 and NF-κB p65 in arterial wall, and attenuated oxidative stress in guinea pigs that have been fed high fat diet. In vitro study further confirmed that niacin decreased the secretion of IL-6 and TNF-α and inhibited NF-κB p65 and notch1 protein expression in oxLDL-stimulated HUVECs and THP-1 macrophages. Moreover, niacin attenuated oxLDL-induced apoptosis of HUVECs as well. In addition, niacin significantly lessened lipid deposition in arterial wall, increased HDL-C and apoA levels and decreased TG and non-HDL-C levels in plasma, and upregulated the mRNA amount of cholesterol 7α-hydroxylase A1 in liver of guinea pigs. These data suggest for the first time that niacin inhibits vascular inflammation in vivo and in vitro via downregulating NF-κB signaling pathway. Furthermore, niacin also modulates plasma lipid by upregulating the expression of factors involved in the process of reverse cholesterol transport.