Epigenetic Upregulation of Carotid Body Angiotensin Signaling Increases Blood Pressure.

Nicotine exposure during pregnancy remains a serious public health concern, with long-term consequences for the developing fetus. One of the most troubling outcomes is an increased risk of high blood pressure (hypertension). Nicotine can cause lasting changes in how the body regulates blood pressure—starting with a tiny but powerful organ called the carotid body. The carotid body (CB) is a small cluster of cells in the neck that helps monitor oxygen levels and regulate breathing and blood pressure. This study found that when pregnant rats were exposed to nicotine, their offspring developed overactive carotid bodies. This overactivity led to increased nerve signals that raised blood pressure—a condition known as CB-mediated hypertension. This study shows that nicotine causes epigenetic changes—chemical modifications that affect how genes are turned on or off. Specifically, a gene called AgtR1, which plays a role in blood pressure regulation, is found to be more active in the carotid bodies of nicotine-exposed offspring. This is due to changes in DNA methylation, a process that can “unlock” certain genes and increase their activity. The study also showed that these changes made the carotid body more sensitive to angiotensin, a hormone that narrows blood vessels and raises blood pressure. When the researchers disrupted the nerve signals from the carotid body, blood pressure in the nicotine-exposed animals dropped—confirming the CB’s central role in this form of hypertension. Understanding how early-life exposures like nicotine alter gene expression and organ function helps scientists design better therapies to reverse or repair this damage. Ultimately, this research highlights how environmental exposures can shape long-term health.