Review
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Pharmacol Ther. Nov 6, 2016; 7(4): 469-476
Published online Nov 6, 2016. doi: 10.4292/wjgpt.v7.i4.469
Bilirubin in coronary artery disease: Cytotoxic or protective?
Nancy Gupta, Tavankit Singh, Rahul Chaudhary, Sushil K Garg, Gurprataap Singh Sandhu, Varun Mittal, Rahul Gupta, Roxana Bodin, Sachin Sule
Nancy Gupta, Sachin Sule, Department of Medicine, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, United States
Tavankit Singh, Department of Medicine, Cleveland Clinic, Cleveland, OH 44195, United States
Rahul Chaudhary, Department of Medicine, Sinai Hospital of Baltimore, Johns Hopkins University, Baltimore, MD 21218, United States
Sushil K Garg, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, United States
Gurprataap Singh Sandhu, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15260, United States
Varun Mittal, Einstein Healthcare Network, Philadelphia, PA 19141, United States
Rahul Gupta, Government Medical College, Amritsar, Punjab 143001, India
Roxana Bodin, Division of Gastroenterology and Hepatobiliary Disease, New York Medical College, Valhalla, NY 10595, United States
Author contributions: All authors contributed to the manuscript; Gupta N, Singh T and Chaudhary R have contributed equally for the paper.
Conflict-of-interest statement: No potential conflicts of interest relevant to this article were reported.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Nancy Gupta, MD, Department of Medicine, Westchester Medical Center, New York Medical College, 40 Sunshine Cottage Rd, Valhalla, NY 10595, United States. drnancygupta87@gmail.com
Telephone: +1-914-5361563 Fax: +1-914-4935827
Received: April 2, 2016
Peer-review started: April 7, 2016
First decision: June 6, 2016
Revised: June 7, 2016
Accepted: August 27, 2016
Article in press: August 29, 2016
Published online: November 6, 2016
Processing time: 211 Days and 21.7 Hours
Abstract

Bilirubin has traditionally been considered a cytotoxic waste product. However, recent studies have shown bilirubin to have anti-oxidant, anti-inflammatory, vasodilatory, anti-apoptotic and anti-proliferative functions. These properties potentially confer bilirubin a new role of protection especially in coronary artery disease (CAD), which is a low grade inflammatory process exacerbated by oxidative stress. In fact, recent literature reports an inverse relationship between serum concentration of bilirubin and the presence of CAD. In this article, we review the current literature exploring the association between levels of bilirubin and risk of CAD. We conclude that current evidence is inconclusive regarding the protective effect of bilirubin on CAD. A causal relationship between low serum bilirubin level and increased risk of CAD is not currently established.

Keywords: Bilirubin; Cytotoxic; Protective; Anti-oxidant; Anti-inflammatory; Anti coronary artery disease; Lipid peroxidation; Gilbert

Core tip: Bilirubin has traditionally been considered a cytotoxic waste product. However, recent studies have shown bilirubin to have anti-oxidant, anti-inflammatory, vasodilatory, anti-apoptotic and anti-proliferative functions. These properties potentially confer bilirubin a new role of protection especially in coronary artery disease (CAD), which is a low grade inflammatory process exacerbated by oxidative stress. In fact, recent literature reports an inverse relationship between serum concentration of bilirubin and the presence of CAD. In this article, we review the current literature exploring the association between levels of bilirubin and risk of CAD.