Comparative study of the effects of cigarette smoke versus next-generation tobacco and nicotine product extracts on inflammatory biomarkers of human monocytes

Research output: Contribution to journalResearch articleContributedpeer-review



Monocytes exhibiting a pro-inflammatory phenotype play a key role in adhesion and development of atherosclerotic plaques. As an alternative to smoking, next-generation tobacco and nicotine products (NGP) are now widely used. However, little is known about their pro-inflammatory effects on monocytes. We investigated cell viability, anti-oxidant and pro-inflammatory gene and protein expression in THP-1 monocytes after exposure to aqueous smoke extracts (AqE) of a heated tobacco product (HTP), an electronic cigarette (e-cig), a conventional cigarette (3R4F) and pure nicotine (nic). Treatment with 3R4F reduced cell viability in a dose-dependent manner, whereas exposure to alternative smoking products showed no difference to control. At the highest non-lethal dose of 3R4F (20%), the following notable mRNA expression changes were observed for 3R4F, HTP, and e-cig respectively, relative to control; HMOX1 (6-fold, < 2-fold, < 2-fold), NQO1 (3.5-fold, < 2-fold, < 2-fold), CCL2 (4-fold, 3.5-fold, 2.5-fold), IL1B (4-fold, 3-fold, < 2-fold), IL8 (5-fold, 2-fold, 2-fold), TNF (2-fold, 2-fold, < 2-fold) and ICAM1 was below the 2-fold threshold for all products. With respect to protein expression, IL1B (3-fold, < 2-fold, < 2-fold) and IL8 (3.5-fold, 2-fold, 2-fold) were elevated over the 2-fold threshold, whereas CCL2, TNF, and ICAM1 were below 2-fold expression for all products. At higher doses, greater inductions were observed with all extracts; however, NGP responses were typically lower than 3R4F. In conclusion, anti-oxidative and pro-inflammatory processes were activated by all products. NGPs overall showed lower responses relative to controls than THP-1 cells exposed to 3R4F AqE.


Original languageEnglish
Pages (from-to)823-833
Number of pages11
Journal Pflügers Archiv : European journal of physiology
Issue number7
Early online date21 Apr 2023
Publication statusPublished - 21 Apr 2023

External IDs

Scopus 85153030402
WOS 000971438800001
Mendeley 8c859443-3966-3c74-8784-7f8060f9bc0e



  • Electronic cigarette (e-cig), Endothelial dysfunction, Heated tobacco product (HTP), Inflammatory biomarkers, Monocyte adhesion molecules, Next-generation tobacco and nicotine products (NGP), Humans, Interleukin-8, Cigarette Smoking/adverse effects, Monocytes, Tobacco, Electronic Nicotine Delivery Systems, Nicotine/pharmacology, Biomarkers, 3R4F aqueous cigarette smoke extract (3R4F AqE)