We have all been there: You are at your computer, working hard and then a yawn hits you. Alternatively, you are on the phone late at night and you start to nod. We all have our late nights burning the midnight oil, but we need our shut-eye.
Now it turns out that sleep deprivation might wreak havoc with your stem cells. New research in mice might (let me emphasize, might) have profound implications for patients undergoing bone marrow stem cell transplants.
This research was led by Dr. Asya Rolls, who formerly worked as a postdoctoral research fellow at Stanford University, but is now an assistant professor at the Israel Institute of Technology.
With regards to the clinical implications of this work, Dr. Rolls said, “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. However, it’s heartening to think that this is not an insurmountable obstacle; a short period of recovery sleep before transplant can restore the donor’s cells’ ability to function normally.”
Rolls and her colleagues used laboratory mice for this study and broke them into two different groups. One group of mice was physically handled by members of the research team for four hours in order prevent them from going to sleep. The other group of mice were not handled and slept soundly in their cages. Then Rolls and her collaborators isolated bone marrow stem cells from the sleepless and well-rested mice. These bone marrow stem cells were then used to them to help reconstitute the bone marrow of twelve different mice that had been given radiation treatments that wiped out their bone marrow stem cells. It is important to note that these donor mice had bone marrow stem cells that glowed when put under a fluorescent light.
The irradiated mice were then examined eight and 16 weeks after they had received the bone marrow stem cell transplants. By taking blood samples, Roll and others measured the production of blood cells by the transplanted bone marrow stem cells. Mind you, the irradiated mice also received some of their own bone marrow stem cells in combination with the bone marrow stem cells from the donor mice. This was to help determine the percentage of blood cells made by the stem cells from the donor mice. Surveys of the blood cells of the irradiated mice showed that donated stem cells from the mouse donors that had a good night’s sleep gave rise to about 26 percent of the examined blood cells. However, bone marrow stem cells from sleepless donor mice only produced approximately 12 percent of the surveyed blood cells.
Next, the Stanford team investigated the ability of the transplanted stem cells to find their way to the bone marrow of the recipient mice, twelve hours after transplantation. When the bone marrow of the donor mice was subjected to fluorescent light, the 3.3 percent of the bone marrow stem cells were from the well-rested donor mice. However, the same experiment in those recipient mice that had received mice had received bone marrow stem cells from the sleep-deprived mice showed that only 1.7 percent of the stem cells in the bone came from the donor mice. Thus the bone marrow stem cells from those mice that had a good night’s sleep were twice as likely to find their way to the bone marrow of the recipient.
When hematopoietic stem cells from the donor mice were tested in culture, stem cells from the sleepless mice showed a weak response to chemical cues found in bone marrow that activate migration to the bone marrow. Conversely, hematopoietic stem cells from the well-rested mice responded much more robustly to these same chemical cues and migrated appropriately.
Think of it; not sleeping for only four hours can decrease the activity of transplanted bone marrow stem cells by up to half. Remember that bone marrow stem cells contain the coveted hematopoietic stem cell population that produces all the blood cells coursing through our bloodstream. When transplanted into recipient animals (or patients), these stem cells must actively find their way to the bone marrow, take up residence there, and begin to produce all the blood cells necessary for the life and health of the recipient. Therefore even a small reduction in the health or activity of hematopoietic stem cells could drastically affect the success of the bone marrow transplant procedure.
Are the effects of sleeplessness permanent? Not at all, at least in mice. Rolls and her team showed that the decrease in bone marrow stem cell activity could be reversed by allowing the sleep-deprived mice to sleep. In fact, in the hands of Rolls and her co-workers, even letting mice get only two hours of recovery sleep effectively restored the activity of their bone marrow stem cells to properly reconstitute the bone marrow of a recipient in a bone marrow transplant procedure.
“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.”
Bone marrow transplants are used to treat patients with blood cancers, immune system disorders or others types of conditions. Each year, many thousands of bone marrow transplant procedures are performed. Therefore refining the bone marrow stem cell transplant procedure is essential to helping patients who need such a procedure.
This study was published in Nature Communications, with Asya Rolls as the lead author, who did her work in the laboratory of Irving Weissman, the director of the Stanford Institute of Stem Cell Biology and Regenerative Medicine.