Scar tissue formed in the heart muscle contributes to the lasting physiological damage caused by a heart attack. A team of medical researchers has now uncovered details about scar tissue production that could lead to treatments that limit this damage (Nat. Cell Biol., DOI: 10.1038/ncb1811). Daniel S. Greenspan of the University of Wisconsin, Madison; Thomas N. Sato of Cornell University's Weill Medical College; and colleagues determined that the protein known as secreted frizzled-related protein 2 (sFRP2) enhances the activity of enzymes responsible for producing collagen, the main component of scar tissue. In the study, mice lacking sFRP2 formed less scar tissue and had better recovery of heart function after a heart attack than normal mice. The researchers are now hunting for compounds that interfere with sFRP2's activity and could help reduce inappropriate collagen formation. Greenspan notes that excess collagen formation occurs in other life-threatening diseases, such as cirrhosis of the liver and interstitial lung disease, which means sFRP2 could be involved in those diseases as well.