It is literally very difficult to mend a broken heart. Despite its importance, the heart is notoriously bad at regenerating itself after injury. If it is damaged – say, by a heart attack – it replaces the lost muscle with scar tissue rather than fresh cells. That weakens it and increases the chance of heart failure later on in life. No wonder that heart disease is the western world’s leading cause of death and illness.

If that picture seems bleak, two teams of scientists have some heartening news for you. The first has found that the heart does actually have the ability to renew its cells, albeit to a limited degree. And the second group has discovered a cocktail of proteins