Abstract

What if we could make our body’s old or sick cells act young again? Surprisingly, the bacteria that cause leprosy may show us how. Previously, we discovered that infecting cells with leprosy bacteria in a laboratory dish “reprogrammed” the cells back to an immature state. The cells may then be able to produce many different types of cells in the body – and maybe even regenerate an organ. 
To test this in an actual animal, we infected nine-banded armadillos with leprosy bacteria. We compared their livers to the livers of uninfected armadillos. The livers of armadillos infected with leprosy were larger than those of uninfected armadillos. Importantly, these larger livers were healthy, with no signs of damage. We performed genetic analyses on the liver cells to determine which genes were active. Our results show that leprosy infection “reprograms” adult liver cells to make them resemble immature liver cells. Maybe someday we can adapt this natural process to regrow aging and damaged livers in humans.