The study adds to the growing scholarship of the importance of sleep and cardiovascular health.
Historic studies have demonstrated the important link to sleep and cardiovascular health, yet Massachusetts General Hospital (MGH) investigators have recently discovered 1 way that sleep protects against the buildup of arterial plaques called atherosclerosis.
Their paper, receiving advance online publication inNature, discusses how sleep helps to regulate the production of inflammatory cells in the bone marrow and for blood vessel health, and how sleep disruption leads to inflammation and heart disease, according to the press release.
In order to determine these results, the MGH team subjected mice genetically programmed to develop atherosclerosis to repeated interruptions in their sleep. There were no changes in weight, cholesterol levels or glucose tolerance compared to mice of the same strain who had uninterrupted sleep, however the subjected mice developed larger arterial plaques and had higher levels of monocytes and neutrophils—inflammatory cells that contribute to atherosclerosis—in their blood vessels.
The sleep-deprived mice had approximately twice the increase in their bone marrow of stem cell production that leads to white blood cells. Hypocretin, a hormone produced in the hypothalamus, was found to control white blood cell production and was found in low amounts in sleep-deprived mice when compared to the high levels in awake mice.
Hypocretin was discovered by investigators to regulate white blood cell production through interaction with neutrophil progenitors in the bone marrow. Neutorphils were also found to induce monocyte production through release of a factor called CSF-1. Experiments with mice who did not have hypocretin revealed that the hormone controls CSF-1 expression, monocyte production, and the development of arterial plaques. In sleep-deprived animals, the drop in hypocretin led to increased CSF-1 production by neutrophils, elevated monocyte production and accelerated atherosclerosis.
"This is a direct demonstration that hypocretin is also an important inflammatory mediator," said Filip Swirski, PhD, senior author of the study, in a prepared statement. "We now need to study this pathway in humans, explore additional mechanisms by which proper sleep maintains vascular health and further explore this newly identified neuro-immune axis."
Mass. General study finds how getting enough sleep reduces cardiovascular disease risk [news release]. Boston, Massachusetts; February 13, 2019: Massachusetts General Hospital.https://www.massgeneral.org/about/pressrelease.aspx?id=2358. Accessed Feb. 28, 2019.