We all know that sleep is important for many biological functions. But I'm still surprised at the breadth of its influence. Today, a former postdoctoral scholar at Stanford, Asya Rolls, PhD, published a fascinating study in Nature Communications showing that blood-forming stem cells from drowsy mice perform more poorly when transplanted into recipient animals. In particular, they are less able to home to the bone marrow, and they generate a smaller proportion of a type of immune cell called a myeloid cell than do stem cells from well-rested mice.

Although the researchers studied only laboratory mice, the possible implications for human transplant recipients (in humans, these procedures are called hematopoietic stem cell transplants, or sometimes bone marrow transplants) are intriguing. As Rolls, who is now an assistant professor at the Israel Institute of Technology, said in our release, "Considering how little attention we typically pay to sleep in the hospital setting, this finding is troubling. We go to all this trouble to find a matching donor, but this research suggests that if the donor is not well-rested it can impact the outcome of the transplantation."

At Stanford, Rolls worked in the laboratory of psychiatrist and sleep medicine specialist Luis de Lecea, PhD, and she collaborated with Wendy Pang, MD, PhD, and Irving Weissman, MD, director of the Stanford Institute of Stem Cell Biology and Regenerative Medicine, to conduct the research.

Despite the fact that sleep deprivation in the donor reduced the efficacy of their stem cells by about 50 percent, all is not lost. From our release:

Although the effect of sleep deprivation was stark in this study, Rolls and her colleagues found that it could be reversed by letting the drowsy mice catch up on their ZZZs. Even just two hours of recovery sleep restored the ability of the animals' stem cells to function normally in the transplantation tests. "Everyone has these stem cells, and they continuously replenish our blood and immune system," said Rolls. "We still don't know how sleep deprivation affects us all, not just bone marrow donors. The fact that recovery sleep is so helpful only emphasizes how important it is to pay attention to sleep."

Previously: In mice, at least, uninterrupted sleep is critical for memory and Bone marrow transplantation: The ultimate exercise in matchmaking

Photo by Eddy Van 3000