James McCully was in the lab extracting tiny structures called mitochondria from cells when researchers on his team rushed in. They’d been operating on a pig heart and couldn’t get it pumping normally again.
McCully studies heart damage prevention at Boston Children’s Hospital and Harvard Medical School and was keenly interested in mitochondria. These power-producing organelles are particularly important for organs like the heart that have high energy needs. McCully had been wondering whether transplanting healthy mitochondria into injured hearts might help restore their function.
The pig’s heart was graying rapidly, so McCully decided to try it. He loaded a syringe with the extracted mitochondria and injected them directly into the heart. Before his eyes, it began beating normally, returning to its rosy hue.