Display options
Share it on

Nicotine Tob Res. 2021 Aug 19; doi: 10.1093/ntr/ntab168. Epub 2021 Aug 19.

Instigators of COVID-19 in Immune Cells are Increased in Tobacco Cigarette Smokers and Electronic Cigarette Vapers Compared to Non-smokers.

Nicotine & tobacco research : official journal of the Society for Research on Nicotine and Tobacco

Theodoros Kelesidis, Yuyan Zhang, Elizabeth Tran, Grace Sosa, Holly R Middlekauff

Affiliations

  1. Department of Medicine, Division of Infectious Disease, David Geffen School of Medicine at UCLA, Los Angeles, California.
  2. Department of Medicine, Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, California.

PMID: 34410424 PMCID: PMC8513409 DOI: 10.1093/ntr/ntab168

Abstract

INTRODUCTION: SARS-CoV-2, the virus responsible for the COVID-19 pandemic, gains entry into the host cell when its Spike protein is cleaved by host proteases TMPRSS2 and furin, thereby markedly increasing viral affinity for its receptor, angiotensin-converting enzyme-2(ACE2). In rodent and diseased human lungs, tobacco cigarette(TCIG) smoke increases ACE2, but the effect of electronic cigarette vaping(ECIG) is unknown. It is unknown whether nicotine (in both TCIGs and ECIGs) or non-nicotine constituents unique to TCIG smoke increase expression of key proteins in COVID-19 pathogenesis.

METHODS: Immune (CD45+) cells collected before the pandemic in otherwise healthy young people, including TCIG-smokers(n=9), ECIG-vapers(n=12) or non-smokers(NS) (n=12) were studied. Using flow cytometry, expression of key proteins in COVID-19 pathogenesis were compared among these groups.

RESULTS: TCIG-smokers and ECIG-vapers had similar smoking or vaping burdens as indicated by similar plasma cotinine levels. TCIG-smokers compared to NS had a significantly increased percentage of cells that were positive for ACE2 (10-fold, p<0.001), TMPRSS2 (5-fold, p<0.001) and ADAM17 (2.5-fold, p<0.001). Additionally, the mean fluorescence intensity (MFI) consistently showed greater mean ACE2 (2.2-fold, p<0.001), TMPRSS2 (1.5-fold, p<0.001), furin (1.1-fold, p<0.05) and ADAM17 (2-fold, p<0.001) in TCIG-smokers compared to NS. In ECIG-vapers, furin MFI was increased (1.15-fold, p<0.05) and TMPRSS2 MFI tended to be increased (1.1-fold, p=0.077) compared to NS.

CONCLUSIONS: The finding that key instigators of COVID-19 infection are lower in ECIG-vapers compared to TCIG-smokers is intriguing and warrants additional investigation to determine if switching to ECIGs is an effective harm reduction strategy. However, the trend towards increased proteases in ECIG-vapers remains concerning.

IMPLICATIONS: This is the first human study to report a marked increase in proteins critical for COVID-19 infection, including ACE2, TMPRSS2 and ADAM17, in immune cells from healthy tobacco cigarette smokers without lung disease compared to e-cigarette vapers and non-smokers. These findings warrant additional investigation to determine if switching to electronic cigarettes may be an effective harm reduction strategy in smokers addicted to nicotine who are unable or unwilling to quit, The increase in proteases in electronic cigarette vapers remains concerning.

© The Author(s) 2021. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: [email protected].

References

  1. Science. 2020 Mar 13;367(6483):1260-1263 - PubMed
  2. J Am Heart Assoc. 2020 Sep 15;9(18):e016983 - PubMed
  3. J Biol Chem. 2005 Aug 26;280(34):30113-9 - PubMed
  4. Dev Cell. 2020 Jun 8;53(5):514-529.e3 - PubMed
  5. Ann Intern Med. 2017 Mar 21;166(6):390-400 - PubMed
  6. Intensive Care Med. 2020 May;46(5):846-848 - PubMed
  7. JAMA Netw Open. 2020 Oct 1;3(10):e2020694 - PubMed
  8. J Adolesc Health. 2020 Oct;67(4):519-523 - PubMed
  9. MMWR Morb Mortal Wkly Rep. 2020 Sep 18;69(37):1310-1312 - PubMed
  10. Nat Med. 2005 Aug;11(8):875-9 - PubMed
  11. Science. 2019 Dec 13;366(6471):1318-1320 - PubMed
  12. Tob Induc Dis. 2021 Feb 04;19:09 - PubMed
  13. Addiction. 2021 Jun;116(6):1319-1368 - PubMed
  14. PLoS One. 2015 Mar 23;10(3):e0121546 - PubMed
  15. Clin Chem Lab Med. 2020 Jun 29;58(9):1415-1422 - PubMed
  16. Toxicol Rep. 2020 Apr 30;7:658-663 - PubMed
  17. J Pediatr Gastroenterol Nutr. 2011 May;52 Suppl 1:S2-3 - PubMed
  18. J Prim Care Community Health. 2021 Jan-Dec;12:21501327211024391 - PubMed

Publication Types

Grant support