Antioxidants Modulate the Antiproliferative Effects of Nitric Oxide on Vascular Smooth Muscle Cells and Adventitial Fibroblasts by Regulating Oxidative Stress Elaine K. Gregory, MD 1 , Ashley K. Vavra, MD 1 , Edward S. Moreira, PhD 1 , George E. Havelka, MD 1 , Qun Jiang, MD 1 , Vanessa R. Lee, BS 1 , Robert Van Lith, MS 2 , Guillermo A. Ameer, ScD 2 , and Melina R. Kibbe, MD 1 1 Division of Vascular Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611 2 Biomedical Engineering Department, McCormick School of Engineering, Northwestern University, Evanston, IL 60201 3 Institute for BioNanotechnology in Medicine, Northwestern University, Chicago, IL 60611 Abstract Background—S-nitrosothiols (SNO) release nitric oxide (NO) through interaction with ascorbic acid (AA). However, little is known about their combined effect in the vasculature. The aim of this study is to investigate the effect of AA on SNO-mediated NO release, proliferation, cell cycle progression, cell death and oxidative stress in vascular cells. Methods—VSMC and adventitial fibroblasts (AF) harvested from the aortae of Sprague Dawley rats were treated with AA, ± S-nitrosoglutathione (GSNO), or ± diethylenetriamine NONOate (DETA/NO). NO release, proliferation, cell cycle progression, cell death, and oxidative stress were determined by the Greiss reaction, [ 3 H]-thymidine incorporation, flow cytometry, trypan blue exclusion, and DCF staining, respectively. Results—AA increased NO release from GSNO 3-fold (p<0.001). GSNO and DETA/NO significantly decreased proliferation, but AA abrogated this effect (p<0.05). Mirroring the proliferation data, changes in cell cycle progression induced by GSNO and DETA/NO were reversed by addition of AA. GSNO- and DETA/NO-mediated increases in oxidative stress were significantly decreased by addition of AA (p<0.001). Conclusion—Despite causing increased NO release from GSNO, AA reduced the antiproliferative and cell cycle effects of GSNO and DETA/NO through modulation of oxidative stress. Keywords Atherosclerosis; peripheral arterial disease; vascular smooth muscle cell proliferation; ascorbic acid; reactive oxygen species; nitric oxide © 2011 Excerpta Medica, Inc. All rights reserved. Corresponding Author: Melina R Kibbe, MD, 676 N. St. Clair Street, #650, Chicago, IL 60611, Office: (312) 503-6701, Fax: (312) 503-1222; mkibbe@nmh.org. This work was presented at the Association of VA Surgeons 35 th Annual Meeting in Irvine, California. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author Manuscript Am J Surg. Author manuscript; available in PMC 2012 November 1. Published in final edited form as: Am J Surg. 2011 November ; 202(5): 536–540. doi:10.1016/j.amjsurg.2011.06.018. NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author Manuscript