Although most victims survive the 735,000 heart attacks that occur annually in the U.S., their heart tissue is often irreparably damaged—unlike many other cells in the body, once injured, heart cells cannot regenerate. According to a new UC San Francisco study, the issue may date back to our earliest mammalian ancestors, which may have lost the ability to regenerate heart tissue in exchange for endothermy—or as it's known colloquially, "warm-bloodedness"—a Faustian evolutionary bargain that ushered in the age of mammals but left modern humans vulnerable to irreparable tissue damage after heart attack.
* This article was originally published here
