# Direct Effects of Waterpipe Smoke Extract on Aortic Endothelial Cells: An In Vitro Study

## TL;DR

This study shows that waterpipe smoke extract harms aortic endothelial cells by causing inflammation, oxidative stress, and cell death.

## Contribution

The study provides new in vitro evidence of direct endothelial damage caused by waterpipe smoke extract.

## Key findings

- WPSE reduces cell viability in a concentration- and time-dependent manner.
- WPSE increases oxidative stress, inflammation, and apoptosis in TeloHAEC cells.
- WPSE activates nuclear factor-κB and HIF-1α pathways in endothelial cells.

## Abstract

Waterpipe smoking (WPS) has adverse health effects that include endothelial dysfunction with mechanisms involving oxidative stress and inflammation. Nonetheless, there is a scarcity of data on the direct impact of WPS on endothelial function. In this study, we assessed the in vitro effects of waterpipe smoke extract (WPSE) on aortic endothelial cell lines, namely the TeloHAEC. The WPSE markedly caused concentration- and time-dependent decreases in cellular viability. When compared with the control, at a concentration of 20 % and an incubation period of 48 h, the WPSE significantly increased the levels of lactate dehydrogenase, and markers of oxidative stress including thiobarbituric acid reactive substances, superoxide dismutase, catalase, and reduced glutathione. Moreover, the concentrations of proinflammatory cytokine (tumor necrosis factor α), and adhesion molecules (E-selectin and intercellular adhesion molecule-1) were also significantly augmented. Likewise, WPSE triggered mitochondrial dysfunction, DNA oxidative damage, as well as apoptosis in TeloHAEC cells. Similarly, cells cultured with WPSE have shown increased expression of phosphorylated nuclear factor-κB and hypoxia-inducible factor 1-α (HIF-1α). In conclusion, our study showed that WPSE triggers endothelial inflammation, oxidative stress, DNA damage, mitochondrial dysfunction, and apoptosis via mechanisms involving the activation of nuclear factor-κB and HIF-1α.