One Minute Marijuana Secondhand Smoke Exposure Substantially Impairs Vascular Endothelial Function
posted 02/06/2016
publication © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.
Original Research
Vascular Medicine
One Minute of Marijuana Secondhand Smoke Exposure Substantially Impairs Vascular Endothelial Function
Xiaoyin Wang, MD1;
Ronak Derakhshandeh, MS1;
Jiangtao Liu, MD2,5;
Shilpa Narayan, BS1,2,†;
Pooneh Nabavizadeh, MD2;
Stephenie Le, BA2,‡;
Olivia M. Danforth, BS1,§;
Kranthi Pinnamaneni, MD1;
Hilda J. Rodriguez, AS2,3;
Emmy Luu, BS2;
Richard E. Sievers, BS2;
Suzaynn F. Schick, PhD4;
Stanton A. Glantz, PhD1,2;
Matthew L. Springer, PhD*,1,2,3
+ Author Affiliations
1Cardiovascular Research Institute, University of California, San Francisco
2Division of Cardiology, University of California, San Francisco
3Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco
4Division of Occupational and Environmental Medicine, University of California, San Francisco
5Department of Cardiovascular Surgery & Electro‐chemotherapy, China‐Japan Friendship Hospital, Beijing, People's Republic of China
↵*Correspondence to:
Matthew L. Springer, PhD, Division of Cardiology, University of California, San Francisco, 513 Parnassus Ave, Box 0124, San Francisco, CA 94143. E‐mail: matt.springer@ucsf.edu
Received May 6, 2016.
Accepted June 2, 2016.
© 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.
This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.
Abstract
Background Despite public awareness that tobacco secondhand smoke (SHS) is harmful, many people still assume that marijuana SHS is benign. Debates about whether smoke‐free laws should include marijuana are becoming increasingly widespread as marijuana is legalized and the cannabis industry grows. Lack of evidence for marijuana SHS causing acute cardiovascular harm is frequently mistaken for evidence that it is harmless, despite chemical and physical similarity between marijuana and tobacco smoke. We investigated whether brief exposure to marijuana SHS causes acute vascular endothelial dysfunction.
Methods and Results We measured endothelial function as femoral artery flow‐mediated dilation (FMD) in rats before and after exposure to marijuana SHS at levels similar to real‐world tobacco SHS conditions. One minute of exposure to marijuana SHS impaired FMD to a comparable extent as impairment from equal concentrations of tobacco SHS, but recovery was considerably slower for marijuana. Exposure to marijuana SHS directly caused cannabinoid‐independent vasodilation that subsided within 25 minutes, whereas FMD remained impaired for at least 90 minutes. Impairment occurred even when marijuana lacked cannabinoids and rolling paper was omitted. Endothelium‐independent vasodilation by nitroglycerin administration was not impaired. FMD was not impaired by exposure to chamber air.
Conclusions One minute of exposure to marijuana SHS substantially impairs endothelial function in rats for at least 90 minutes, considerably longer than comparable impairment by tobacco SHS. Impairment of FMD does not require cannabinoids, nicotine, or rolling paper smoke. Our findings in rats suggest that SHS can exert similar adverse cardiovascular effects regardless of whether it is from tobacco or marijuana.
Key Words:
artery
cannabis
endothelium
flow‐mediated dilation
marijuana
nitric oxide synthase
secondhand smoke
smoking
vasodilation
