Adults who reduced their sleep for six weeks had increased markers of inflammation.
The study published in the Journal of Experimental Medicine(link is external).
“What we’re learning is that sleep modulates the production of cells that are the protagonists — the main players — of inflammation,” said Filip K. Swirski, Ph.D., lead study author. and director of the Icahn Cardiovascular Research Institute. Mount Sinai School of Medicine, New York. “Good quality sleep reduces this inflammatory burden.”
To assess these mechanisms, the researchers investigated the associations between sleep and monocyte production in humans and mice, building on results from previous mathematical models. They analyzed how sleep disruptions increased circulating levels of these immune cells and altered the bone marrow environment.
In a collaborative study led by Marie-Pierre St-Onge, Ph.D., at Columbia University in New York, 14 adults enrolled in the clinical research trial. They each participated in a six-week study arm that either simulated getting enough sleep (about 7.5 hours a night) or created a lack of sleep. To model sleep restriction, adults reduced nighttime sleep by 1.5 hours, getting about 6 hours of sleep each night. Sleep conditions were separated by a six-week “washout” period, during which participants returned to their normal sleep patterns.
Morning and afternoon blood samples were taken during the fifth and sixth weeks for each sleep condition. Researchers found that when adults didn’t get enough sleep, they had higher levels of circulating monocytes in the afternoon. They also had higher numbers of immune stem cells in their blood and signs of immune activation.
“The stem cells were imprinted or genetically modified under the influence of sleep restriction,” Swirski said. “The change is not permanent, but they continue to reproduce at a higher rate for weeks.”
Higher production of immune cells creates a more homogeneous immune environment, which may accelerate clonal hematopoiesis, an age-related condition that has been linked to increased risks of cardiovascular disease.
Previous studies have identified genetic mutations that lead to the proliferation of hematopoietic stem cells. However, this study found that pressure on the hematopoietic system, in this case through sleep restriction, produced similar results without the driver mutations.
“Sleep impacts the optimal functioning of nearly every cell and organ in the body,” said Marishka K. Brown, Ph.D., director of the National Center on Sleep Disorders Research, located within the National Heart, Lung , and Blood Institute (NHLBI). ). “The mechanistic insights from this study support findings from larger population studies, which have shown that sleep may be protective against a variety of conditions, including heart disease, cancer, and dementia.”
The study authors said their findings also underscored the importance of establishing healthy sleep habits early in life, which can reduce the severity of other inflammatory conditions such as sepsis. Most adults should get 7-8 hours of uninterrupted sleep each night. Older adults need about 7-9 hours, while children 11-17 years old need about 8-10 hours.
The study was partially funded by the NHLBI and the National Center for Advancing Translational Sciences.
To learn more about sleep health, visit https://www.nhlbi.nih.gov/health-topics/education-and-awareness/sleep-health.
To learn more about the NIH Sleep Research Plan, visit www.nhlbi.nih.gov/sleep-research-plan/about.
About the National Heart, Lung, and Blood Institute (NHLBI): NHLBI is the world leader in conducting and supporting research into heart, lung and blood diseases and sleep disorders that advances scientific knowledge, improves public health and saves lives. For more information, visit https://www.nhlbi.nih.gov.
About the National Institutes of Health (NIH): The NIH, the country’s medical research agency, comprises 27 institutes and centers and is part of the US Department of Health and Human Services. The NIH is the primary federal agency that conducts and supports basic, clinical, and translational medical research, and studies the causes, treatments, and cures for common and rare diseases. For more information about the NIH and its programs, visit www.nih.gov.
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McAlpine CS, Kiss MG, Zuraikat FM, et al. Sleep exerts lasting effects on the function and diversity of hematopoietic stem cells. J Exp Med. 2022; doi: 10.1084/jem.20220081(link is external)