Illustration of a heart cell

A popular over-the-counter heartburn medication caused laboratory blood vessel cells to age quicker, in a new study published in the American Heart Association journal Circulation Research.

Reflux, often called heartburn, occurs when stomach acid backs up into the esophagus, causing irritation and damage. Mild reflux is fairly common, but frequent, severe occurrences known as GERD for gastroesophageal reflux disease, can cause significant discomfort and may require treatment.

The U.S. Food and Drug Administration estimates that one in 14 Americans have used the over-the-counter proton pump inhibitor, which reduces acid produced by the stomach.

After recent evidence linked long-term PPI use to several serious illnesses — including heart disease, kidney disease and dementia — researchers at Houston Methodist Research Institute sought to identify how the drug increases risk by studying its effect on blood vessel cells.

The researchers discovered that long-term exposure to PPIs “accelerated biological aging in human endothelial cells that line the inside of blood vessels. When healthy, human endothelial cells create a Teflon-like coating that prevents blood from sticking. When older and diseased, the endothelium becomes more like Velcro, with blood elements sticking to the vessel to form blockages.”

They also found that long-term PPI exposure impairs acid production by the lysosomes in the cells lining the blood vessel walls. Lysosome — the part of the cell that typically clears waste products — didn’t produce enough acid to clear waste. In turn, the buildup of waste caused the cell to age rapidly.

“Lysosomes are like the garbage disposal of cells,” said John P. Cooke, M.D., Ph.D., study lead author and professor and chair of the Department of Cardiovascular Sciences at the HMRI and director of the Houston Methodist Research Institute Center for Cardiovascular Regeneration in Texas. “They need to generate acid to get rid of cellular rubbish, and when cellular rubbish accumulates, the cells age faster.”

Although PPIs can be effective for short-term use, they’re not for extended treatment. PPIs don’t require a prescription or doctor’s supervision, which can lead to overuse.

“With the knowledge that PPIs are being used by millions of people for indications and durations that were never tested or approved, it may be time for the pharmaceutical industry and regulatory agencies to re-visit the specificity and the safety of these agents,” Cooke said. “Unless otherwise indicated, physicians should consider PPIs only for short-term use for relief of symptoms of GERD, since we now have a ‘smoking gun’ that helps explain the consistent observational evidence of increased risk.”

Other long-term treatments for GERD might include H2 antagonists, lifestyle modifications, and in severe cases, surgical approaches, Cooke said.