We often think of the different processes of our body as separate - digestion, respiration, and circulation - but there are constant clues that the systems of our body are intimately coordinated. The most painful reminder of this interdependence is in illness. Gastroesophageal reflux disease, or GERD, for example, is probably one of the most common ailments affecting Americans. While its true incidence is not known, up to 40 percent of the nation may suffer from its symptoms, including heartburn and regurgitation. Frequently, people with GERD go on to develop asthma-like symptoms, a disease process involving an entirely different organ system. Up until now, the guess has been that people with GERD send stomach acid up into the lungs, leading them to cough and wheeze. Now, a study from Duke University confirms this idea in the laboratory for the first time. Principal investigator Dr. Shu Lin, an assistant professor of surgery and immunology at Duke University, inserted stomach acid into the lungs of mice. The researchers found that those mice went on to develop changes in the immune system of the lungs similar to those seen in human patients with asthma. "There's a lot of people affected by both asthma and GERD," says Lin, "and now we have a model that lets us work on the connection between both in the laboratory."
BOTTOM LINE: This study for the first time provides physiological proof that gastroesophageal reflux disease is linked to asthma. CAUTIONS: The studies were done in mice, not humans. WHAT'S NEXT: The authors plan to figure out precisely how stomach acid might lead to changes in the immune system of the lungs.
WHERE TO FIND IT: The European Journal of Clinical Investigation, July 17.
BOTTOM LINE: If a new theory about aging is correct, it might be possible to reverse genetic imbalances that develop over time, slowing or halting aging.
CAUTIONS: Kim stresses that although humans have a similar regulatory model called GATA-3, there is no evidence that it has anything to do with longevity, and it's unknown whether human aging is regulated by a similar developmental pathway.
WHAT'S NEXT: Kim and his colleagues are using their results from worm studies to study aging in mice and humans.
WHERE TO FIND IT: Cell, July 24.