Early one Saturday morning in March 2015, the hospital got a call from a hospital in Maine. Doctors there wanted to transfer to Boston Children’s a newborn baby boy whose heart had been deprived of oxygen during surgery to fix a congenital defect. (Snip)He injected 1 billion mitochondria, in about a quarter of a teaspoon of fluid. Within two days, the baby had a normal heart, strong and beating quickly. “It was amazing,” Emani said.