0198 Bidirectional Predictors Between Baseline and Recovery Sleep and DNA Strand Breaks During Sleep Deprivation and Psychological Stress

Abstract Introduction We have previously shown that DNA strand breaks change during total sleep deprivation (TSD) and psychological stress. We determined whether baseline sleep measures predicted endogenous DNA strand breaks (ESB), which occurred during normal aerobic metabolism, and radiation-induced DNA strand breaks (ISB), which occurred from blood cells irradiated ex vivo, during TSD and psychological stress. We also assessed whether these markers predicted recovery sleep measures. Methods We conducted a five-day experiment under highly controlled conditions in 15 healthy adults (ages 29-52; 6 females). DNA strand breaks via blood samples were collected: 1) after two baseline 8h time-in-bed (TIB) nights (B1, B2); 2) during TSD morning (TSD AM; after 25h of TSD); 3) during TSD evening following a modified Trier Social Stress Test, which induced psychological stress (TSD PM; after 34h of TSD); and 4) after two recovery nights of 8-10h TIB (R1, R2). Wrist actigraphy assessed sleep indices during the B2 and R1 nights. Simple linear regression assessed predictive relationships between B2 and R1 sleep metrics and TSD AM and TSD PM ESB and ISB. Simple linear regression also was conducted in males and females separately for significant main results. p< 0.05 was significant. Results Later B2 sleep offset significantly predicted lower TSD PM ESB (r=−0.670; β=−1.684), explaining 44.9% of the overall variance, and 59.9% (r=−0.774; β=−2.492) of the variance in males. Notably, B2 sleep measures did not significantly predict TSD ISB. In addition, greater TSD AM ISB significantly predicted longer R1 sleep duration (r=0.536; β=10.289), explaining 28.7% of the overall variance, and 81.8% (r=0.904; β=31.069) of the variance in females. By contrast, TSD ESB did not significantly predict R1 sleep measures. Conclusion For the first time, we demonstrate that baseline sleep offset predicted ESB during TSD and psychological stress, explaining a high percentage of the variance, particularly in males, but did not predict ISB. By contrast, ISB, but not ESB during TSD and psychological stress predicted recovery sleep duration explaining a high percentage of the variance, particularly in females. Our results underscore crucial relationships, mechanisms and molecular biomarkers between sleep health and radiation-induced and endogenous DNA strand breaks. Support (if any) NASA grants NNX14AN49G; 80NSSC20K0243 (NG)