Drug developers and research scientists have been on a mission to treat cardiovascular diseases, in part, by activating a heart protein dubbed APJ. Researchers at Sanford-Burnham Medical Research Institute and the Stanford University School of Medicine found, however, that activating APJ isn't always a good thing. That's because the protein can sense mechanical changes when the heart is in danger and subsequently propel the organ toward failure. The key, the scientists found, is that it is important to activate APJ in a way that also involves the hormone apelin, which can promote embryonic heart development, normal blood pressure and the formation of new blood vessels. Details are published in the July 18 issue of Nature. Release