RT Journal Article SR Electronic T1 Niacin promotes cardiac healing after myocardial infarction through activation of the myeloid prostaglandin D2 receptor subtype 1 JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP jpet.116.238261 DO 10.1124/jpet.116.238261 A1 Deping Kong A1 Juanjuan Li A1 Yujun Shen A1 Guihu Liu A1 Shengkai Zuo A1 Bo Tao A1 Yong Ji A1 Ankang Lu A1 Michael Lazarus A1 Richard M Breyer A1 Ying Yu YR 2017 UL http://jpet.aspetjournals.org/content/early/2017/01/06/jpet.116.238261.abstract AB Niacin is a well-established drug used to lower cholesterol and prevent cardiovascular disease (CVD) events. However, niacin also causes cutaneous flushing side effects due to release of the proresolution mediator prostaglandin (PG) D2. Recent randomized clinical trials have demonstrated that addition of niacin with laropiprant (a PGD2 receptor subtype 1 [DP1] blocker) to statin-based therapies does not significantly decrease the risk of CVD events but increases the risk of serious adverse events. Here, we tested whether, and how, niacin beneficial effects in vivo myocardial ischemia requires the activation of the PGD2/DP1 axis. Here we try to test whether niacin facilitates cardiac recovery from myocardial infarction (MI) through activation of the PGD2/DP1 axis. Myocardial infarction (MI) was reproduced by ligation of the left anterior descending branch of the coronary artery in mice. We found that niacin increased PGD2 release in macrophages and shifted macrophages to M2 polarization both in vitro and in vivo by activation of DP1 and accelerated inflammation resolution in zymosan-induced peritonitis in mice. Moreover, niacin treatment facilitated wound healing and improved cardiac function after MI through DP1-mediated M2 bias and timely resolution of inflammation in infarcted hearts. In addition, we found that niacin intake also stimulated M2 polarization of peripheral monocytes in humans. Collectively, niacin promoted cardiac functional recovery after ischemic myocardial infarction through DP1-mediated M2 polarization and timely resolution of inflammation in hearts. These results indicated that DP1 inhibition may attenuate the cardiovascular benefits of niacin.