New research on mouse neural stem cells investigates the effects of nicotine on the brain with short and long-term use of e-cigarettes.
Cigarettes, which contain the highly addictive drug nicotine, are harmful and have been shown to cause oral, throat, and respiratory system cancers. Electronic cigarettes, or vapes, are currently marketed to cigarette smokers as a safer alternative to traditional cigarettes. Unfortunately, they are now common among adolescents as well as people who did not previously smoke cigarettes, creating potential issues regarding nicotine dependence and addiction.
Although electronic cigarettes are thought to be safer than their traditional counterparts, this is not necessarily true. There is insufficient knowledge in the scientific community on their long-term effects on overall health. Nicotine itself could potentially be harmful to the brain and body, even when the chemicals in cigarettes are removed. Recent research from the University of California, Riverside, investigated the effects of nicotine to determine if electronic cigarettes damage the brain.
The researchers used cultured neural stem cells from mice and exposed them to vapour from Vuse e-liquid, a popular electronic cigarette brand. Stem cells develop into specialized cells with specific functions, and they were used in this experiment because they are more sensitive to stress than specialized cells. They are commonly used in studies that determine the effects of toxin exposure.
The study found that exposure of the stem cells to nicotine-infused e-liquids induced a mechanism called stress-induced mitochondrial hyperfusion (SIMH). SIMH is a survival response where round mitochondria fuse together to form long mitochondrial networks to protect each other from degradation. Nicotine binds to receptors in the neural stem cell membrane, causing them to open and the neural stem cells to flood with calcium. Too much calcium in the mitochondria is harmful because the mitochondria swell and develop an abnormal structure and function. Damaged stem cell mitochondria can increase the rate of aging as well as cause neurodegenerative diseases.
This study suggests that more research is needed to determine the long-term effects of e-cigarette use on brain health, as current research is insufficient to guarantee their safety.
Written by Avery Bisbee
Reference: Zahedi, A., Phandthong, R., Chaili, A., Leung, S., Omaiye, E., & Talbot, P. (2019). Mitochondrial Stress Response in Neural Stem Cells Exposed to Electronic Cigarettes. IScience,16, 250-269. doi:10.1016/j.isci.2019.05.034\
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