Impact of > 24 h sustained wakefulness and subsequent recovery sleep on time-dependent changes in microRNA factors of individuals with post-acute phase mild traumatic brain injury

IntroductionThe purpose of the present study was to determine whether mild traumatic brain injury (mTBI+) results in latent changes in microRNA expression profiles across an episode of total sleep deprivation (TSD). MethodsSeven previously concussed (mTBI+) adults (24.5 {+/-} 5.3 y.o.) and 6 non-concussed control adults (mTBI-; 24.8 {+/-} 1.6 y.o.) underwent 24 h TSD (T2) preceded by 8 h baseline sleep (T1; BSL) and followed by 8 h recovery (T3; REC) sleep. Salivary microRNA expression was assessed across the entire study. ResultsSubjects (mTBI+ and mTBI-) had differential expression of salivary microRNA targets across TSD. mTBI+ subjects had greater change to microRNA expression profiles compared to mTBI- subjects between T1 and T3. DiscussionAlthough there is some evidence that TSD may unmask latent changes in gene expression in mTBI+ subjects, a definitive conclusion was precluded by differences in baseline sleep in mTBI+ (vs. mTBI-) subjects measured through polysomnography (not shown). However, this study is unique in that the mTBI+ subjects were exposed to a sleep deprivation challenge very shortly after medical clearance from mTBI demonstrating lingering neurobiological impacts of mTBI.