Impact of e-cigarettes on colonic mucosa and the role of recovery: involvement of oxidative and inflammatory pathway

Abstract

Electronic cigarettes (e-cigarettes) (EC) are often advertised as a safer alternative to conventional cigarettes. Its widespread use has led to increased interest in its adverse health effects, thanks to few restrictions and a lack of regulatory guidelines. The study aimed to evaluate the influence of exposure to e-cigarette aerosol inhalation in rat colon model and conduct a follow-up after cessation of exposure. The experiment included 30 male adult Albino rats. The animals were divided into three groups: group I (control), non-exposed animals; group II (exposed), was exposed to electronic cigarette liquid vapor for four consecutive weeks; and group III (recovery), was followed up for another 4 weeks after exposure to an e-cigarette as exposed group and for the same duration. In the exposed group, malondialdehyde (MDA) and total nitric oxide (NO) increased significantly in colonic tissue, while superoxide dismutase (SOD) decreased. On histological examination, colonic mucosa showed distortion and loss of its epithelial lining with heavy inflammatory cell infiltration. Also, there was a significant decrease in periodic acid-Schiff-positive goblet cells and area percent of proliferating cell nuclear antigen expression. Tumor necrosis factor-alpha (TNFα) expression significantly increased in colonic mucosa. After 4 weeks of EC cessation, the colonic mucosal histological structure showed recovery with downregulated TNFα immunoexpression and restored oxidant/antioxidant balance. In conclusion, the usage of electronic cigarettes resulted in marked pathological alterations in the colonic mucosa, which could be attributed to oxidative and inflammatory stresses. In contrast, the cessation of exposure led to recovery.

Chronic Exposure to Both Electronic and Conventional Cigarettes Alters Ileum and Colon Turnover, Immune Function, and Barrier Integrity in Mice

“…By contrast, in the colon, CS had no effect on apoptosis or cell proliferation, whereas both Mb18W and Mb30W e-cig exposure induced evident limitation of cell proliferation, demonstrated by histological crypt loss, epithelial surface decrease and a reduced number of proliferative cells in crypts. According to our results, a decrease in colon cell proliferation was reported in mice exposed to e-cig liquid vapor [ 24 ]. In contrast, to our knowledge, CS was reported as promoting or inhibiting colon cancer-cell proliferation [ 21 , 39 , 40 , 41 ], and its effect on normal colonic mucosa has never been studied before.…”

“…Nevertheless, an in vivo and ex vivo study reported that e-cig led to a compromised gut barrier and was associated with chronic gut inflammation [ 23 ]. In rats, e-cig exposure for 4 weeks induced oxidative stress, colonic mucosa epithelial loss, and inflammatory infiltration, as well as a decrease in goblet cells [ 24 ]. In mice, daily inhalation of mango-flavoured e-cig for one month was associated with colon inflammation [ 25 ].…”

A Review on Inflammatory Bowel Diseases: Recent Molecular Pathophysiology Advances

“…Finally, tobacco also has the effect of altering intestinal permeability and motility. 106 It is relatively complex to answer the question about the existence of a link between eating habits and IBD. Initially, it is necessary to distinguish between the impact of diet on the onset of the disease and the impact on the evolution and on the severity of the flare-up phases.…”

The risk profile of electronic nicotine delivery systems, compared to traditional cigarettes, on oral disease: a review

“…However, the consensus on the effects of ENDS on oral health needs to be further strengthened ( 22 ). Studies have shown that these devices still have harmful effects on the respiratory ( 23 , 24 ), nervous ( 25 , 26 ), reproductive ( 27 , 28 ), and digestive systems ( 29 ), and they should be considered as carcinogenic factors due to their nicotine content and other additives ( 30 – 32 ). In spite of this, the risks of ENDS may also have been underestimated due to the vast amount of advertising claiming that ENDS pose less or no harm.…”