Getting a good night’s sleep supports immune function, study shows

Getting a good night’s sleep supports the normal production and programming of hematopoietic stem cells, a building block of the body’s innate immune system, according to a small study supported by the National Institutes of Health in humans and mice. Sleep has long been linked to immune function, but researchers found that getting enough of it influenced the environment in which monocytes, a type of white blood cell, form, develop and prepare to support immune function. This process, hematopoiesis, occurs in the bone marrow.

The study published in Journal of Experimental Medicine.

What we are learning is that sleep modulates the production of cells that are the protagonists – the main actors – of inflammation. Good quality sleep reduces that inflammatory load.”

Filip K. Swirski, Ph.D., lead author of the study and director of the Cardiovascular Research Institute at the Icahn School of Medicine at Mount Sinai, N.Y.

To assess these mechanisms, the researchers studied associations between sleep and monocyte production in humans and mice, which extended the findings of previous mathematical models. They looked at how sleep interruptions increased circulating levels of these immune cells and changed the environment in the bone marrow.

In a collaborative study led by Marie-Pierre St-Onge, Ph.D., at Columbia University, New York City, 14 adults were enrolled in the clinical research trial. They each participated in a six-week study arm that either emulated getting enough sleep (about 7.5 hours each night) or created sleep deficiency. To model sleep restriction, the adults reduced their nightly sleep by 1.5 hours, sleeping about 6 hours each night. The sleep conditions were separated by a six-week “washout” period, during which the participants returned to their normal sleep patterns.

Blood samples were collected in the morning and evening during the fifth and sixth weeks for each sleep condition. The researchers found that when adults did not get enough sleep, they had higher levels of circulating monocytes in the afternoon. They also had increased numbers of immune stem cells in their blood and evidence of immune activation.

“Stem cells have been imprinted or genetically altered under the influence of sleep restriction,” Swirski said. “The change is not permanent, but they continue to self-replicate at a higher rate for weeks.”

Increased immune cell production creates a more homogeneous immune environment, which can accelerate clonal hematopoiesis, an age-related condition that has been linked to an increased risk of cardiovascular disease.

Previous studies have identified genetic mutations that drive hematopoietic stem cell proliferation. However, this study found that putting pressure on the hematopoietic system, in this case through sleep restriction, produced similar results without the driving mutations.

“Sleep affects the optimal function of almost every cell and organ in the body,” said Marishka K. Brown, Ph.D., director of the National Sleep Disorders Research Center, located within the National Heart, Lung Institute and Blood (NHLBI). ). “The mechanistic insight of this study supports the findings of larger population studies, which have shown that sleep may be protective against a range of conditions, including heart disease, cancer and dementia.”

The study authors said their findings also underscore the importance of establishing healthy sleep patterns early in life, which may reduce the severity of other inflammatory conditions, such as sepsis. Most adults should get 7 to 8 hours of uninterrupted sleep each night. Older adults need 7 to 9 hours, while children ages 11 to 17 need 8 to 10 hours.

The study was partially funded by the NHLBI and the National Center for Advancing Translational Sciences.

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National Institutes of Health

Magazine Reference:

McAlpine, CS, et al. (2022). Sleep exerts long-lasting effects on hematopoietic stem cell function and diversity. Journal of Experimental Medicine. doi.org/10.1084/jem.20220081.

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