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

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

The study published in the Journal of Experimental Medicine.

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

Filip K. Swirski, Ph.D., senior study author and director of the Cardiovascular Research Institute at the Icahn School of Medicine at Mount Sinai, New York City

To assess these mechanisms, researchers studied associations between sleep and monocyte production in humans and mice, building on findings from previous mathematical models. They analyzed how sleep disturbances increased the circulating levels of these immune cells and changed the environment in the bone marrow.

In a joint study led by Marie-Pierre St-Onge, Ph.D., at Columbia University, New York City, 14 adults participated in the clinical research study. They each participated in a six-week study group that either emulated to get enough sleep (about 7.5 hours a night) or caused sleep deprivation. To model sleep restriction, adults reduced their nighttime sleep by 1.5 hours — about 6 hours of sleep per night. Sleep conditions were separated by a six-week “washout” period, during which the participants returned to their normal sleep patterns.

Morning and afternoon blood samples were collected during the fifth and sixth weeks for each sleep state. 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 the blood and evidence of immune activation.

“The stem cells are imprinted, or genetically altered, under the influence of sleep restriction,” Swirski said. “The change isn’t permanent, but they continue to replicate themselves at a faster rate for weeks.”

Higher production of immune cells creates a more homogeneous immune environment, which may accelerate clonal hematopoiesis, an age-related condition linked to an increased risk of cardiovascular disease.

Previous studies have identified genetic mutations that stimulate the proliferation of hematopoietic stem cells. However, this study found that pressurizing the hematopoietic system, in this case through sleep restriction, produced similar results without the driver mutations.

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

The study authors said their findings also underlined the importance of establishing good sleep patterns at an early age, which can reduce the severity of other inflammatory conditions such as sepsis. Most adults should get 7-8 hours of uninterrupted sleep every night. Older adults need about 7-9 hours, while children 11-17 years need about 8-10 hours.

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