Human subjects show an increase in salivary IL-6.

<p>(<b>A</b>) Subjective sleepiness as assessed using the Stanford Sleepiness Scale was increased following 30 h of wakefulness. Each subject served as their untreated circadian-matched control; t-test p = 0.0008. (<b>B</b>–<b>D</b>) Cognitive performance, assessed using the psychomotor vigilance task (PVT), was impaired following 30 h of wakefulness: (<b>B</b>) Lapses increased during waking compared to controls; t-test, p = 0.03. (<b>C</b>) Mean reaction time, expressed as 1/RT) slowed; t-test p = 0.001. (<b>D</b>) Reaction times in the slowest 10% also slowed t-test p = 0002. (<b>E</b>) Levels of IL-6 protein from human saliva after 30 hours of waking. Levels in sleep deprived subjects (n = 16) are expressed as a % of that their own untreated circadian-matched sample (con); t-test p = 0.042.</p

Overall strategy to exploit the evolutionary conservation of sleep to identify and validate biomarkers of sleepiness.

<p>Overall strategy to exploit the evolutionary conservation of sleep to identify and validate biomarkers of sleepiness.</p

Immune-related transcripts are associated with increased sleep drive in <i>Drosophila</i> clock mutants.

<p>(<b>A</b>) Immune related transcripts are substantially increased in <i>cyc⁰¹</i> mutants following 7 h of sleep deprivation but are not consistently activated when 7 h of waking is induced by starvation; data are expressed as % change from untreated siblings. Experiments were conducted in constant darkness (DD). (<b>B</b>–<b>E</b>) Transcript levels for <i>AttB</i>, <i>Dro</i>, <i>Mtk</i> and <i>Drs</i> in <i>tim⁰¹</i> mutants following 3, 6, 9 and 12 h of sleep deprivation. Immune related transcripts are consistently elevated following 9 and 12 hour sleep deprivation (Light Green) but not after 3 or 6 h of sleep deprivation when no sleep rebound is observed (dark Green).</p

The <i>Drosophila</i> integrin <i>scb</i> and Human <i>ITGA5</i> are modified by sleep loss.

<p>(<b>A</b>) <i>scb</i> is elevated following caffeine administration but not after waking induced by methamphetamine. (<b>B</b>) <i>scb</i> is elevated in sleep deprived <i>cyc⁰¹</i> mutants but is not increased when waking is induced by starvation. (<b>C</b>) <i>scb</i> mRNA levels remain low following deprivations that do not activate homeostatic mechanisms (3 and 6 h SD), but are elevated following deprivations that activate homeostatic mechanisms (9 and 12 h SD). (<b>D</b>–<b>E</b>) Salivary <i>ITGA5</i> transcripts are increased in humans following 30 h of wakefulness while 24 h of wakefulness do not quite reach significance; t-test and p = 0.04 and p = 0.056 respectively. Each subject serves as their own circadian matched untreated control; data are expressed as a percent change from control.</p

IL-6 is elevated in serum of chronic total sleep deprived rats.

<p>(<b>A</b>) Energy Expenditure expressed as % of home cage controls (HCC, n = 7) is significantly increased in total sleep deprived (TSD, n = 7) rats compared to yoked controls (TSC, n = 6); One way ANOVA F_(2,11) = 6.79, p = .012, * modified Bonferroni test p<0.05 (<b>B</b>) Serum concentrations of IL-6 protein from individual TSD, TSC, and HCC rats. Arrows denote which animals tested positive for bacteria. (<b>C</b>) Mean concentration of IL-6 from individual rats in (B). One way ANOVA F_(2,17) = 5.22, p = .017 * p<0.05 modified Bonferroni test <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0061016#pone.0061016-Keppel1" target="_blank">[58]</a>. Data are presented as mean±SEM.</p

Transcripts for immune-related genes are elevated in flies under conditions of increased sleepiness.

<p>(<b>A</b>) Immune-related transcripts are significantly elevated in <i>Cs</i> flies following a night of sleep deprivation; data are expressed as % of untreated circadian-matched siblings. (<b>B</b>) <i>Cs</i> flies with normal total sleep time but spontaneously fragmented sleep (average night sleep bouts <30 min) exhibit an increase in immune-related transcripts expressed as % change from siblings with consolidated sleep and matched by total sleep time; error bars are present but not visible given the magnitude of the changes. Abbreviations: <i>Drosocin</i> (<i>Dro</i>), <i>Attacin-B</i> (<i>AttB</i>), <i>Drosomycin</i> (<i>Drs</i>), <i>Metchnikowin</i> (<i>Mtk</i>), <i>Immune induced molecule 23</i> (<i>IM23</i>), and <i>Defensin</i> (<i>Def</i>).</p