A new study from the University of Chicago has shed light on why smoking is increasingly linked to mental decline, offering fresh insight into how nicotine may affect the brain over time.
Health experts have long warned that smoking increases the risk of dementia, including conditions like Alzheimer’s disease. Previous research showed that heavy smokers in middle age could more than double their risk of developing such conditions later in life.
The latest findings suggest this connection may be rooted in a direct biological pathway between the lungs and the brain.
Lung-brain connection explained
According to the study, nicotine activates a previously unknown mechanism involving specialized lung cells known as pulmonary neuroendocrine cells (PNECs).
These cells release tiny particles called exosomes in response to nicotine exposure.
Researchers found that these exosomes can interfere with the brain’s ability to regulate iron levels—an essential process for maintaining healthy nerve cells.
An imbalance in iron can:
- Damage neurons
- Disrupt energy systems within brain cells
- Trigger processes linked to neurodegenerative diseases like Parkinson’s disease
What researchers say
Co-author and postdoctoral researcher Cui Zhang said the findings demonstrate a “clear lung-brain connection,” helping explain why smoking is associated with cognitive decline.
The study was published in the medical journal Science Advances and was conducted using laboratory models and stem cell-derived PNECs.
While the results offer promising insights, researchers caution that the findings are based on laboratory models. More studies are needed to confirm whether the same mechanism occurs in humans.
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