For more than 80 years, scientists and doctors have assumed that the cause of damage to the esophagus associated with acid reflux in patients with gastroesophageal reflux disease (GERD) was due to stomach acid. But damage is actually caused by inflammation, say researchers at UT Southwestern Medical Center and Dallas VA Medical Center.

Instead of being caused by stomach acid rising into the esophagus and damaging the lining of the esophagus by chemical burns, their research indicates that the damage is the result of an inflammatory response spurred by the secretion of proteins called cytokines.

"Although this radical change in the concept of how acid reflux damages the esophagus of GERD patients will not change our approach to its treatment with acid-suppressing medications in the near future, it could have substantial long-term implications," said senior author Dr. Stuart Spechler, professor of Internal Medicine at UT Southwestern and chief of the Department of Gastroenterology at the Dallas VA Medical Center.

 Researchers speculate GERD might one day be treated with drugs that target the cytokines or inflammatory cells that actually cause the damage.

The research builds on previous work in mice demonstrating that it takes several weeks from the time stomach acid is introduced into the esophagus before damage occurs.

"A chemical burn should develop immediately, as it does if you spill battery acid on your hand," said Spechler.

In the recent study, researchers looked at patients who had reflux esophagitis (an injury to the lining of the esophagus) that had been successfully treated by medicines called proton pump inhibitors (PPIs).

The researchers thought that GERD might redevelop if PPIs were stopped, providing an opportunity to observe the early changes of GERD. In 11 of 12 patients with reflux esophagitis, changes to the esophagus reoccurred after the PPIs were stopped.

But the changes were not consistent with chemical burns. Instead, the findings supported the new idea that refluxed stomach acid stimulates the esophagus to make small proteins called cytokines, which then sets up the process of inflammation.

"This study challenges some of the long-held beliefs about how gastroesophageal reflux damages the esophageal mucosa in patients with gastroesophageal reflux disease," said study author Dr. Kerry Dunbar.

GERD is a very common condition that affects 20 percent of adult Americans. In severe cases, it can be associated with a dangerous condition called Barrett’s esophagus, which can lead to esophageal cancer.

The research appears online in the Journal of the American Medical Association.