Researchers have long wondered why elderly people suffer more infections and have a greater chance of developing myeloid leukemia, a type of blood cancer, than younger people do. Now, research in mice suggests that the aging of blood-producing stem cells could be responsible for both conditions.
With age, the body of a person or other animal loses its capacity to sustain its tissues and organs. "Since we know the cells mediating this maintenance are stem cells, it doesn't take a great leap of faith to think that stem cells are at the heart of that failure," says Derrick Rossi of Stanford University.
To examine whether the aging of stem cells contributes to infections and leukemia, Rossi and his colleagues irradiated young and old mice to kill off their blood-making stem cells. The scientists then transplanted such stem cells from young donor mice into elderly irradiated animals and from old donors into young irradiated animals.
After several weeks, the researchers