Nicotine may damage arteries

NEW ORLEANS — Even smokeless cigarettes may cause damage that can lead to hardening of the arteries, a new study implies.

Vascular smooth muscle cells wrap around blood vessels and help control blood flow and pressure. But inflammation and chemicals, such as those found in cigarette smoke, can turn the cells into miniature drills that chew through connective tissue, allowing muscle cells to burrow into blood vessels. Once inside, the cells and other debris clump into artery-clogging plaques.

Nicotine is one chemical that helps turn normal muscle cells into invaders, Chi-Ming Hai, a physiologist at Brown University in Providence, R.I., reported December 15 at the American Society for Cell Biology’s annual meeting. When exposed to nicotine, smooth muscle cells already riled up by inflammation formed ringlike structures that start the invasion. A toxin that blocks nicotine from latching on to its receptor on muscle cells could stop the incursion.

The finding comes as a surprise because scientists thought that other chemicals in smoke were responsible for bodily damage, while nicotine caused addiction. Electronic cigarettes were thought to be safer because they deliver nicotine without other potentially dangerous chemicals. But, Hai says, “the data suggest that nicotine is not harmless.”