Summary: A new study reports shorter sleep duration can suppress the immune system and could answer why people tend to get sick when they don’t get enough sleep.
Source: University of Washington Health Sciences.
Study one of first conducted outside of sleep lab.
Many people report getting sick when they don’t get enough sleep. A new study helps explain why.
Researchers took blood samples from 11 pairs of identical twins with different sleep patterns and discovered that the twin with shorter sleep duration had a depressed immune system, compared with his or her sibling. The findings were published Jan. 25 in the journal Sleep.
“What we show is that the immune system functions best when it gets enough sleep. Seven or more hours of sleep is recommended for optimal health,” said lead author Dr. Nathaniel Watson, co-director of the UW Medicine Sleep Center at Harborview Medical Center.
A unique feature of this study was to employ identical twins in order to control for the large genetic determinant to humans’ sleep duration. Researchers say genetics account for 31 to 55 percent of sleep duration and behavior and environment account for the remainder.
Dr. Sina Gharib, director of UW Medicine’s Computational Medicine Core at the Center for Lung Biology, and the paper’s senior author, explained that a lot of existing data shows that curtailing sleep – for a limited time in the laboratory setting – can increase inflammatory markers and activate immune cells. Little is known, though, about the effects of longstanding short sleep duration under natural conditions. This study employed “real world” conditions, he said, and showed for the first time that chronic short sleep shuts down programs involved in immune response of circulating white blood cells.
“The results are consistent with studies that show when sleep deprived people are given a vaccine, there is a lower antibody response and if you expose sleep deprived people to a rhinovirus they are more likely to get the virus,” Watson said. “This study provides further evidence of sleep to overall health and well-being particularly to immune health.
The researchers, citing data from the Centers for Disease Control, said that over the past century people in the United States are sleeping an estimated 1.5 to two hours less, and about one-third of the working population sleeps less than six hours per night.
“Modern society, with its control of light, omnipresent technology and countless competing interests for time, along with the zeitgeist de-emphasizing sleep’s importance, has resulted in the widespread deprioritization of sleep,” they wrote.
Funding: The work was supported by NIH grants K23HL0833350, P30NR011400, ITHS Sleep Pilot Grant and a University of Washington General Clinical Research Pilot Grant.
Source: Bobbi Nodell – University of Washington Health Sciences
Image Source: NeuroscienceNews.com image is credited to Yair Pinto.
Original Research: Full open access research for “Transcriptional Signatures of Sleep Duration Discordance in Monozygotic Twins” by NF Watson, MD, MS; D Buchwald, MD; JJ Delrow, PhD; WA Altemeier, MD; MV Vitiello, PhD; AI Pack, MBChB, PhD; M Bamshad, MD; C Noonan, MS; and SA Gharib, MD in Sleep. Published online January 25 2017 doi:10.1093/sleep/zsw019
Transcriptional Signatures of Sleep Duration Discordance in Monozygotic Twins
Habitual short sleep duration is associated with adverse metabolic, cardiovascular, and inflammatory effects. Co-twin study methodologies account for familial (eg, genetics and shared environmental) confounding, allowing assessment of subtle environmental effects, such as the effect of habitual short sleep duration on gene expression. Therefore, we investigated gene expression in monozygotic twins discordant for actigraphically phenotyped habitual sleep duration.
Eleven healthy monozygotic twin pairs (82% female; mean age 42.7 years; SD = 18.1), selected based on subjective sleep duration discordance, were objectively phenotyped for habitual sleep duration with 2 weeks of wrist actigraphy. Peripheral blood leukocyte (PBL) RNA from fasting blood samples was obtained on the final day of actigraphic measurement and hybridized to Illumina humanHT-12 microarrays. Differential gene expression was determined between paired samples and mapped to functional categories using Gene Ontology. Finally, a more comprehensive gene set enrichment analysis was performed based on the entire PBL transcriptome.
The mean 24-hour sleep duration of the total sample was 439.2 minutes (SD = 46.8 minutes; range 325.4–521.6 minutes). Mean within-pair sleep duration difference per 24 hours was 64.4 minutes (SD = 21.2; range 45.9–114.6 minutes). The twin cohort displayed distinctive pathway enrichment based on sleep duration differences. Habitual short sleep was associated with up-regulation of genes involved in transcription, ribosome, translation, and oxidative phosphorylation. Unexpectedly, genes down-regulated in short sleep twins were highly enriched in immuno-inflammatory pathways such as interleukin signaling and leukocyte activation, as well as developmental programs, coagulation cascade, and cell adhesion.
Objectively assessed habitual sleep duration in monozygotic twin pairs appears to be associated with distinct patterns of differential gene expression and pathway enrichment. By accounting for familial confounding and measuring real life sleep duration, our study shows the transcriptomic effects of habitual short sleep on dysregulated immune response and provides a potential link between sleep deprivation and adverse metabolic, cardiovascular, and inflammatory outcomes.
“Transcriptional Signatures of Sleep Duration Discordance in Monozygotic Twins” by NF Watson, MD, MS; D Buchwald, MD; JJ Delrow, PhD; WA Altemeier, MD; MV Vitiello, PhD; AI Pack, MBChB, PhD; M Bamshad, MD; C Noonan, MS; and SA Gharib, MD in Sleep. Published online January 25 2017 doi:10.1093/sleep/zsw019