Nicotine Exerts Cytotoxic Effects in a Panel of Healthy Cell Lines and Strong Irritating Potential on Blood Vessels

Abstract

The use of tobacco products is a major global public health issue, as it is the leading cause of preventable death worldwide. In addition, nicotine (NIC) is a key component of electronic and conventional cigarettes. Although nicotine’s addictive potential is well known, its health effects are not entirely understood. Thus, the main objective of the present study was to evaluate its toxicological profile both in vitro, at the level of three healthy cell lines, and in ovo, at the level of the chorioallantoic membrane. Five different concentrations of nicotine were used in keratinocytes, cardiomyocytes, and hepatocytes for the purpose of evaluating cell viability, cell morphology, and its impact on nuclei. Additionally, the hen’s egg test on the chorioallantoic membrane (HET-CAM) method was used to assess the biocompatibility and irritant potential of the chorioallantoic membrane. Across all cell lines studied, nicotine was proven to be significantly damaging to cell viability, with the highest concentration tested resulting in less than 2% viable cells. Moreover, the morphology of cells changed dramatically, with alterations in their shape and confluence. Nicotine-induced cell death appears to be apoptotic, based on its impact on the nucleus. In addition, nicotine was also found to have a very strong irritating effect on the chorioallantoic membrane. In conclusion, nicotine has an extremely strong toxicological profile, as demonstrated by the drastic reduction of cell viability and the induction of morphological changes and nuclear alterations associated with cellular apoptosis. Additionally, the HET-CAM method led to the observation of a strong irritating effect associated with nicotine.

Comparative in Vitro and in Ovo Study of the Cytotoxic Profile of Nicotine From Electronic Cigarettes Versus Chewing Gum

“…According to a previous study, nicotine from conventional cigarettes induces a strong condensation of chromatin, fragmentation of nuclei and the appearance of apoptotic bodies in the nuclei of human keratinocytes. All these effects are more intense than those observed in the present case with nicotine derived from electronic cigarettes and chewing gum [9]. Moreover, Ruiz and colleagues examined the effects of nicotine on the nuclei of human mesenchymal stem cells, which are fibroblast-like cells found in several tissues, including the skin.…”

“…Photographs were taken with the 20x objective, and the scale bar indicates 50 µm Electronic cigarettes have been controversially discussed in the past regarding their negative impact on the cardiovascular system [13]. The effects of nicotine on cardiomyocyte nuclei have been evaluated previously and it has been concluded that nicotine from conventional cigarettes is much more toxic at the cellular level than the nicotine studied in the present study [9]. The process of apoptosis is known to involve changes at the molecular and morphological levels.…”

“…Furthermore, a study conducted at the level of oral keratinocytes (OKC) indicated that nicotine induces transcriptional and translational changes, leading to disruptions in the cell cycle and cellular differentiation genes [2]. It is important to mention that in a previous study conducted by our research group, the effect of nicotine from conventional cigarettes on human keratinocytes has been evaluated, and it is concluded that nicotine from conventional cigarettes is significantly more cytotoxic than nicotine from electronic cigarettes [9]. As for nicotine contained within chewing gum, to the best of our knowledge, no in vitro assessments have been conducted on human keratinocytes to investigate its effects.…”

“…According to the study conducted by Basma and colleagues regarding the effects of nicotine from electronic cigarettes, it is shown that it has a strong cytotoxic effect on cardiomyocytes, increasing the production of reactive oxygen species and altering genes involved in cell proliferation and apoptosis [3]. On the other hand, the study conducted by Chioran and colleagues revealed that nicotine from conventional cigarettes is more cytotoxic at the level of cardiomyocytes than nicotine from electronic cigarettes and chewing gum [9]. To our knowledge, no studies have been conducted on the effects of nicotine from chewing gum on cardiomyocytes.…”

“…In a previous study, nicotine from conventional cigarettes was evaluated in relation to human keratinocyte morphology. Based on the results of the study, it appeared that it has a significant effect on cellular confluence and shape [9]. In a study conducted by Pagano and colleagues, Heat-not-burn tobacco (IQOS) was evaluated at the level of fibroblasts and keratinocytes.…”