Constant lack of sleep negatively impacts immune system stem cells, increasing risk of inflammatory disease and heart disease – Neuroscience News

Summary: Sleep deprivation alters the structure of DNA in immune cells and increases the number of immune cells, causing them to overreact and trigger inflammation. The study found that catching up on sleep did not reverse this effect.

Source: Mount Sinai Hospital

Chronic, inadequate sleep can negatively affect immune cells, which can lead to inflammatory diseases and cardiovascular disease, according to a new study from the Icahn School of Medicine at Mount Sinai. More specifically, the constant loss of an hour and a half of sleep each night may increase your risk.

The research, published September 21 in the Journal of Experimental Medicine, shows for the first time that sleep alters the structure of DNA in the immune stem cells that produce white blood cells — also known as immune cells — and this may have a long-lasting impact on inflammation and contribute to inflammatory diseases.

Immune cells fight infection, but when the numbers of these cells get too high, they overreact and cause inflammation. The study is also the first to show that catching up on sleep does not reverse the effects of sleep disorders.

“This study begins by identifying the biological mechanisms that link sleep and immunological health over the long term. It shows that sleep disorders in humans and mice have a profound impact on how immune cells are programmed and produced, causing them to lose their protective powers and actually worsen infections — and these changes are long-lasting.

“This is important because another important observation is that sleep reduces inflammation and, conversely, that sleep disruption increases inflammation,” says lead author Filip Swirski, PhD, director of the Cardiovascular Research Institute at Icahn Mount Sinai.

“This work emphasizes the importance of adults getting a regular seven to eight hours of sleep a day to prevent inflammation and disease, especially for those with underlying medical conditions.”

A team of researchers analyzed 14 healthy adults who regularly slept eight hours a night. First, the researchers observed that they slept at least eight hours a night for six weeks. They took blood and analyzed their immune cells. Then the same group of adults reduced their sleep time by 90 minutes every night for six weeks and had their blood and immune cells analyzed again.

At the end of the study, the researchers compared the blood and cell samples from the full night’s sleep and restricted sleep periods.

All participants had significant changes in their immune cells (also known as hematopoietic cells) due to lack of sleep – there were more of them and the DNA structure was altered. After six weeks of sleep restriction, they had an increased number of immune cells.

The researchers also analyzed sleep in mouse models. Groups of mice were either allowed to sleep undisturbed or had sleep fragmentation, in which they were awakened throughout the night for 16 weeks. Then, sleep-fragmented mice underwent uninterrupted sleep recovery for ten weeks.

During these undisturbed, fragmented and sleep-recovery phases, the researchers extracted immune stem cells and immune cells from mice, analyzed them and compared them at the end of the experiment.

The results in mice were consistent with the results in humans. They showed that all mice with fragmented sleep had significant changes in their immune stem cells, producing increased numbers of immune cells, and also showed evidence of rewiring and reprogramming.

A notable finding from the group of mice was that even after recovery from sleep, the immune stem cells retained this rewiring structure and continued to produce extra white blood cells, leaving the mice vulnerable to inflammation and disease.

“Our results suggest that sleep recovery is not able to fully reverse the effects of poor sleep. Even after weeks of restful sleep, we can detect a molecular imprint of insufficient sleep in immune stem cells.

“This molecular imprinting can cause cells to respond in inappropriate ways, leading to inflammation and disease,” says co-investigator Cameron McAlpine, PhD, assistant professor of medicine (cardiology) at Icahn Mount Sinai.

“It was surprising that not all stem cell clusters reacted the same way to lack of sleep. There were some stem cell clusters that multiplied and increased in number, while other clusters became smaller. This reduction in overall diversity and aging of the immune stem cell population is a major contributor to inflammatory and cardiovascular disease.”

Financing: The National Heart, Lung, and Blood Institute and the National Center for Advancing Translational Sciences, part of the National Institutes of Health, helped fund this study.

About this news from sleep and inflammation research

Author: Ilana Nikravesh
Source: Mount Sinai Hospital
Contact: Ilana Nikravesh – Mount Sinai Hospital
Picture: The image is in the public domain

Original research: The results appear in Journal of Experimental Medicine