A new study has found e-cigarettes can trigger a stress response in neural stem cells, which are vital cells in the brain. The research was conducted by a team at the University of California, Riverside.
Stem cells are present throughout our lives. Over time they become specialized cells that are part of specific functions in the body like brain cells and blood cells. That is why they can help scientist better understand how exposure to toxicants, like cigarette smoke, can impact our bodies and health.
Researchers are still trying to determine how chemicals in electronic cigarettes (ECs) affect neural stem cells. "Although originally introduced as safer, ECs, such as Vuse and JUUL, are not harmless," Atena Zahedi, first author of the research paper,told a news portal. Adding, "Even short-term exposure can stress cells in a manner that may lead, with chronic use, to cell death or disease. Our observations are likely to pertain to any product containing nicotine."
However, by using cultured mouse neural stem cells, the team was able to spot the mechanism at play that causes stem cell toxicity due to ECs, which is known as "stress-induced mitochondrial hyperfusion (SIMH).
"SIMH is a protective, survival response," lead author of the study Prue Talbot, a professor in the Department of Molecular, Cell and Systems Biology, told a news portal. Adding, "Our data show that exposure of stem cells to e-liquids, aerosols, or nicotine produces a response that leads to SIMH."
Zahedi explains how stem cells are affected by SIMH. "The high levels of nicotine in ECs lead to a nicotine flooding of special receptors in the neural stem cell membrane," Zahedi told a news portal. Adding, "Nicotine binds to these receptors, causing them to open up. Calcium and other ions begin to enter the cell. Eventually, a calcium overload follows."
Zahedi further explained: "If the nicotine stress persists, SIMH collapses, the neural stem cells get damaged and could eventually die."
Researchers especially warn pregnant women and young people to be extra careful and reduce their exposure to e-cigarettes. "Their brains are in a critical developmental stage," Talbot told a news portal. Adding, "Nicotine exposure during prenatal or adolescent development can affect the brain in multiple ways that may impair memory, learning, and cognition. Furthermore, addiction and dependence on nicotine in youth are pressing concerns. It's worth stressing that it is nicotine that is doing damage to neural stem cells and their mitochondria. We should be concerned about this, given that nicotine is now widely available in ECs and their refill fluids."
The study's findings were originally published in iScience.
