Whole blood genome-wide gene expression profile in males after prolonged wakefulness and sleep recovery.

Although the specific functions of sleep have not been completely elucidated, the literature has suggested that sleep is essential for proper homeostasis. Sleep loss is associated with changes in behavioral, neurochemical, cellular, and metabolic function as well as impaired immune response. Using high-resolution microarrays we evaluated the gene expression profiles of healthy male volunteers who underwent 60 h of prolonged wakefulness (PW) followed by 12 h of sleep recovery (SR). Peripheral whole blood was collected at 8 am in the morning before the initiation of PW (Baseline), after the second night of PW, and one night after SR. We identified over 500 genes that were differentially expressed. Notably, these genes were related to DNA damage and repair and stress response, as well as diverse immune system responses, such as natural killer pathways including killer cell lectin-like receptors family, as well as granzymes and T-cell receptors, which play important roles in host defense. These results support the idea that sleep loss can lead to alterations in molecular processes that result in perturbation of cellular immunity, induction of inflammatory responses, and homeostatic imbalance. Moreover, expression of multiple genes was downregulated following PW and upregulated after SR compared with PW, suggesting an attempt of the body to re-establish internal homeostasis. In silico validation of alterations in the expression of CETN3, DNAJC, and CEACAM genes confirmed previous findings related to the molecular effects of sleep deprivation. Thus, the present findings confirm that the effects of sleep loss are not restricted to the brain and can occur intensely in peripheral tissues.

Apolipoprotein E polymorphisms and sleep quality in obstructive sleep apnea syndrome.

BACKGROUND: The purpose of this study was to evaluate the influence of polymorphism on sleep parameters of Obstructive Sleep Apnea Syndrome (OSAS) patients. METHODS: Patients were genotyped after a full-night polysomnography using the large Epidemiologic Sleep Study of São Paulo population-based sample. RESULTS: Individuals who carry the APOE ε2 allele showed longer sleep latency, lower sleep efficiency and higher numbers of arousals/hour, when compared to ε3 allele homozygous and carriers of ε4 allele (p<0.05). These findings remained significant even after correction for potential confounders, such as sex, age and African genetic ancestry. CONCLUSION: The APOE polymorphisms may modulate the effects of intermittent hypoxia and sleep fragmentation in the sleep architecture of OSAS patients, and that the presence of the ε2 allele may serve as a biological marker for the identification of a subgroup of patients who are more likely to suffer with OSAS detrimental effects on sleep, impacting not only the daily functioning, but also their quality of life.

Influence of genetic ancestry on the risk of obstructive sleep apnoea syndrome.

The aim of the present study was to evaluate the influence of ethnicity on the risk of developing obstructive sleep apnoea syndrome (OSAS) using genomic analysis methods to estimate ancestry. DNA samples were obtained from 1,010 individuals participating in the São Paulo Epidemiologic Sleep Study, who underwent full-night polysomnography. A total of 31 genetic ancestry-informative markers were selected in order to estimate individual admixture proportions. Of patients with a diagnosis of OSAS, a higher number self-reporting Caucasian ethnicity (65.3%), as well as an increased percentage of European ancestry (78.2±16.7%) and lower percentage of West African ancestry (16.1±15.3%), than among individuals without OSAS (53.6, 73.5±18.1 and 20.1±16.8%, respectively) (p<0.001) was observed. Moreover, after correcting for sex, age, body mass index and socioeconomic status, logistic regression demonstrated that European ancestry was significantly associated with an increased risk of manifesting OSAS (OR 2.80, 95% CI 1.11-7.09). Conversely, West African ancestry was associated with a reduced risk of the OSAS phenotype (OR 0.26, 95% CI 0.09-0.72). This is the first study to incorporate genomic analysis methods to measure the influence of ethnicity on the risk of OSAS. Since genetically determined ancestry may not capture unmeasured cultural and lifestyle differences, the contribution of environmental factors to the current findings should not be disregarded.

Dopamine transporter regulation during four nights of REM sleep deprivation followed by recovery--an in vivo molecular imaging study in humans.

OBJECTIVES: To assess the influence of total or selective REM sleep deprivation on the dopamine transporter (DAT) densities and sleep patterns of healthy volunteers. DESIGN: Prospective study. SETTING: Evaluation of polysomnography recordings and DAT density after 4 nights of selective REM sleep deprivation followed by 3 nights of sleep recovery compared to a control group and a group that was subjected to 2 nights of total sleep deprivation. Single positron emission computed tomography and [99mTc]TRODAT-1 were used to assess the cerebral DAT density in the striatum at baseline, after REM sleep deprivation and total sleep deprivation as well as after sleep recovery. Blood was collected daily to examine prolactin and estradiol levels, which were correlated with dopaminergic activity. PATIENTS OR PARTICIPANTS: Thirty healthy male volunteers ranging from 19 to 29 years of age were randomly assigned to one of three experimental groups after giving written informed consent (10 non-sleep deprived, 10 total sleep deprived, and 10 REM sleep deprived). MEASUREMENTS AND RESULTS: Four nights of REM sleep deprivation and 2 nights of total sleep deprivation induced distinct and heterogeneous patterns of sleep recovery. No significant modulation of DAT availability was observed within groups. In the recovery nights, changes in cortisol, prolactin and estradiol concentrations were significantly correlated with specific sleep stages in the total and REM sleep deprived groups. In addition, DAT density was positively correlated with estradiol concentration and inversely associated with SWS latency only after total sleep deprivation. CONCLUSION: Our study demonstrates that although sleep deprivation did not promote significant alterations in DAT density within the striatum, there were significant correlations among transporter availability, hormonal concentrations and sleep parameters.