bluuebunny/crossref_metadata_2025 huggingface dataset:
0018 Whole Genome Sequencing Study Identifies Novel Variants Associated with Intrinsic Circadian Period in Humans
Authors: Smieszek S P
Published: May 2020

Introduction

Non-24 is a circadian rhythm disorder in which the master body clock runs either slightly earlier or, more commonly in the disorder, longer than 24 hours.

Methods

We conducted the first whole genome sequencing study of a non-24 population of 174 individuals that we identified as being totally blind with Non-24 Disorder. We have directly tested the association between SNPs and circadian period length (tau) (n=69). Linear regression corrected for PCs and covariates identified a strong signal in HCN1, Brain Cyclic Nucleotide-Gated Channel 1, HCN1.

Results

HCN1 channel is responsible for the feedback on the rods regulating the dynamic range of light reactivity under dim or intermediate light conditions. Minor allele rs72762058 associated with longer tau, a difference of 12 minutes, and mean tau of 24.71. In Drosophila there is only one HCN channel encoding gene, DmIh. Interestingly, DmIh mutant flies display alterations in the rest:activity pattern, and altered circadian rhythms, specifically, arrhythmic behavior or a shorter period in constant darkness.

We report a variant that associated with longer tau. In addition, we identify others variants that strongly associate with tau, such as a missense variant (rs16989535), (minor allele associated with longer tau), within DEPDC5, GATOR Complex Protein). Subjects carrying the rare allele have a period > 25.2. DEPDC5 is part of GATOR1 complex, together with NPRL2 and NPRL3acts to inhibit the mTORC1 pathway. The GATOR1 seizure phenotype consists mostly of focal seizures, often sleep-related and drug-resistant and is associated with focal cortical dysplasia (20%). mTOR signaling is part of the photic entrainment pathway in the SCN, it regulates autonomous clock properties in a variety of circadian oscillators. Light-induced mTORC1 activation appears to be important for photic entrainment of the SCN clock, as rapamycin modulates light-induced phase shifts of wheel-running and body temperature rhythms in mice.

Conclusion

We identify variants in HCN1 and DEPDC5 implicated in significantly longer tau. Knowledge of the circadian clock and period length is not only essential for understanding of the basic clockwork mechanisms but also could provide insights into mechanistic links between circadian dysfunctions and human diseases such as epilepsy.

Support

Vanda Pharmaceuticals
0022 Klotho Genetic Variants Mediate the Association Between Obstructive Sleep Apnea and Short Telomere Length
Authors: Tempaku P F , D’Almeida V , Andersen M L , Belangero S I , Tufik S
Published: May 2020

Introduction

The core features of obstructive sleep apnea (OSA) can potentially contribute to the acceleration of telomere shortening mechanisms. Among these factors, klotho reduction can contribute since it is associated with accelerated systemic inflammation and oxidative stress and has recently been associated with OSA. Also, decreased levels of klotho are implicated in the regulation of telomerase activity. Therefore, we aimed to evaluate the effect of common genetic variants (SNPs) on KLOTHO gene on the association between OSA and short telomere length.

Methods

As part of the Sao Paulo Epidemiologic Sleep Study cohort, 1,042 individuals answered questionnaires, underwent polysomnography and had blood collected for DNA extraction. OSA was defined according to AHI equal or greater than 15 events per hour. Leukocyte telomere length (LTL) was measured through qPCR and SNPs were genotyped by microarray.

Results

LTL was significantly shorter in OSA compared to controls in a severity-dependent manner (B=0.055, CI=0.007–0.102, p=0.02). Among the 43 SNPs analyzed, we observed that 4 SNPs (rs525014, rs7982726, rs685417 and rs9563124) significantly mediated the association between OSA and short LTL (B=0.046, df=1, p=0.005; B=0.044, df=1, p=0.007; B=0.045, df=1, p=0.006; B=0.044, df=1, p=0.007; respectively). Furthermore, this association was under an additive model since having one or two alleles of the alternative variants were significantly associated with shorter LTL.

Conclusion

We could conclude that klotho opens a new venue in OSA research and would be applicable to prevent the consequences of short telomeres in individuals with OSA.

Support

This work was supported by grants from AFIP, FAPESP and CAPES.
0025 Circadian Dysregulation of DNA Repair and Increased Endogenous and Exogenous Sensitivity to DNA Damage Precipitate Elevated Cancer Risk Associated with Night Shift Work
Authors: Van Dongen H , Koritala B , McDermott J E , Porter K I , Arshad O A , Gajula R P , Mitchell H D , Arman T , Manjanatha M , Gaddameedhi S
Published: May 2020

Introduction

The elevated cancer risk associated with night shift work is poorly understood. To investigate whether circadian disruption may play a role, we assessed the circadian transcriptome and its association with hallmark cancer pathways, as well as sensitivity to endogenous and exogenous sources of DNA damage, after in-laboratory simulated shift work.

Methods

N=14 healthy humans (aged 22-34y; 10m, 4f) were exposed to a simulated night shift schedule (daytime sleep: 10:00-18:00) or a simulated day shift schedule (nighttime sleep: 22:00-06:00) for 3 days (n=7 in each condition). After the simulated shift schedule, subjects underwent a 24h constant routine protocol, during which blood was collected every 3h. Lymphocytes were extracted from the blood samples and subjected to transcriptome analysis using a NanoString multiplex assay. We evaluated 726 mRNA cancer hallmark targets (NanoString PanCancer Pathway Panel) and 17 circadian clock genes, with 18 arrhythmic internal controls. Gene expression was analyzed for circadian rhythmicity using mixed-effects cosinor analysis. Further, lymphocytes were investigated for DNA damage using an alkaline comet assay and immunofluorescence assessment of DNA damage response biomarkers BRCA1 and γH2AX. Lymphocytes collected at 07:30 and 19:30 were also exposed to ionizing radiation (2.5Gy) and DNA damage response assessments were repeated.

Results

Simulated night shift caused widespread disruption of circadian rhythmicity, as measured under constant routine, for core clock genes and the transcriptome of cancer hallmark pathways. The DNA repair pathway showed significant enrichment of rhythmic genes (p<0.05) after the simulated day shift schedule only. Following simulated night shift, lymphocytes showed induction of endogenous DNA damage, with extended tail in the comet assay (p<0.001), and higher percentage of lymphocytes with BRCA1 and γH2AX foci (p<0.01). Lymphocytes collected at 19:30 showed enhanced impact of ionizing radiation as indicated by increased prevalence of cells with BRCA1 and γH2AX foci (p<0.05).

Conclusion

Circadian dysregulation of DNA repair mechanisms and increased sensitivity to DNA damage following night shift work may increase genomic instability and precipitate elevated cancer risk in night shift workers.

Support

NIH grants ES022640 and CA227381, CDMRP award W81XWH-18-1-0100, and Pacific Northwest National Laboratory BRAVE investment under DOE contract DE-AC05-76RL01830.
0032 Timing of Daily Rhythm of Cardiac Autonomic Control Contributes to Weight Loss Resistance, Independent of Daily Energy Intake and Physical Activity Level
Authors: Yang H , Garaulet M , Li P , Bandin C , Lin C , Lo M , Hu K
Published: May 2020

Introduction

Obesity is a major health problem. Many treatments have been designed to help overweight/obese people to lose weight, but their effectiveness is highly variable. The same treatments may work for some persons while others have no responses — weight loss resistance. We tested whether the daily rhythm of cardiac autonomic control contributes to weight loss resistance.

Methods

We studied 39 overweight/obese Caucasian women (BMI>25; age: 21–62 years old) who completed (1) an obesity dietary treatment of up to 30 weeks with weekly assessments of body weight, and (2) ambulatory monitoring of electrocardiogram (ECG) for up to 3.5 days. Heartbeat intervals were derived from ECG. Cardiac autonomic control was assessed in each 1-h bin by examining the temporal correlation in heartbeat fluctuations — a nonlinear measure that quantifies the delicate dynamic interplay between sympathetic and vagal outflows. Daily rhythm was estimated using the cosinor analysis.

Results

Weight loss was highly variable (range: 0.68%-21.78 % of initial body weight). The correlation in heartbeat fluctuations displayed a 24-h rhythm (p<0.0001) with fewer correlations (more random) during the nighttime. The phase (peak timing) of the rhythm was highly variable, i.e., 10AM to 8PM for most participants, and after midnight in four participants. Weight loss evolution depended on the phase (p=0.006) in a nonlinear manner. Specifically, participants with the phase between 2PM-8PM lost weight faster than those with phases before 2PM and those after 8PM. The effect was independent of total energy intake, physical activity level, and sleep/wake schedules.

Conclusion

Cardiac autonomic control in overweight/obese women displayed a daily rhythm. The timing of the rhythm had previously un-identified contributions to weight loss. The inter-individual differences in the timing may reflect different circadian regulation of autonomic function and its interaction with the daily behavioral cycle.

Support

This work was supported by NIH grants R01AG048108, RF1AG059867, RF1AG064312, R01AG017917, and R01NS078009.
0033 Recurrent Circadian Disruption While Minimizing Sleep Loss in Humans Impairs Glucose Tolerance Only in The Presence of High-Fat Diet
Authors: Zitting K , Yuan R K , Vujovic N , Klerman E B , Quan S F , Scheer F A , Wang W , Buxton O M , Williams J S , Duffy J F , Czeisler C A
Published: May 2020

Introduction

Nearly 14% of Americans experience chronic circadian disruption due to shift work, increasing their risk of obesity and cardiometabolic disorders. These disorders are also exacerbated by modern eating habits such as frequent snacking and consumption of high-fat foods. Here we used a forced desynchrony protocol to investigate the effect of 3 weeks of recurrent circadian disruption (RCD) with minimal sleep loss on glucose metabolism in humans on a lower or higher fat diet (LFD and HFD, respectively).

Methods

Six healthy adults (38-69yrs; 3f) participated in a 37-day inpatient protocol with LFD (25–27% fat) and 15.67-hr fasting duration, or HFD (45–50% fat) and 13-hr fasting duration. The protocol included three weeks of RCD consisting of 28-hr “days” with 11.67-hr sleep opportunities (=10hrs/24hr). Glucose and insulin responses to a standardized breakfast were conducted at baseline, at an aligned circadian phase after 2–3 weeks of exposure to RCD, and after 1 week of recovery. Frequent blood samples were assayed for glucose and insulin; the Area-Under-Curve was calculated from start of breakfast through postprandial minute 180.

Results

Total Sleep Time was similar in Baseline and RCD in both groups. Participants on the LFD showed no change in glucose AUC during RCD compared to Baseline. Insulin AUC was lower during RCD (p=0.0269) and Recovery (p=0.0443) than Baseline. In contrast, participants on the HFD showed a significant increase in glucose AUC during RCD compared to Baseline (p<0.0001); AUC returned to Baseline during Recovery. There was no significant change in insulin AUC on the HFD.

Conclusion

RCD (in the absence of sleep loss) led to impaired glucose tolerance when combined with HFD, but not when combined with LFD. These results suggest that LFD may be part of healthy strategies for people experiencing RCD.

Support

Study supported by P01AG009975 and conducted in the Brigham and Women’s Hospital Center for Clinical Investigation, part of Harvard Clinical and Translational Science Center supported by UL1TR001102. Authors supported by a fellowship from the Finnish Cultural Foundation (KMZ); T32HL007901 and F32HL143893 (RKY); T32HL007901 and F32AG051325 (NV); K24HL105664 (EBK); R01HL118601 (FAJLS).
0037 Melanopsin Driven Pupil Responses and Physical Activity: Stability of Activity from Day-to-Day in Winter in Seasonal Affective Disorder
Authors: Roecklein K A , Wescott D L , Smagula S F , Soehner A M , Franzen P L , Hasler B P
Published: May 2020

Introduction

The post-illumination pupil response (PIPR) is a measure of the responsivity of intrinsically photosensitive retinal ganglion cells (ipRGCs), and reflects the cell biology of the photoentrainment pathway projecting from the retina to the circadian clock. Adequate signaling from the ipRGCs in the retina to the circadian clock is necessary to result in robust circadian output which we hypothesize would increase inter-daily stability (IS), a non-parametric modeling technique that examines stability of rest activity rhythms across successive days.

Methods

Participants were aged 18–66 years and recruited from the greater Pittsburgh area during the Winter with Seasonal Affective Disorder who completed both actigraphy and pupillometry (n = 16). PIPR measures were collected after a 1 second red or blue light pulse, and are calculated as the Net difference between red and blue at multiple time frames: at 6 seconds post stimulus (PIPR 6), from 10–30 seconds post-stimulus (PIPR 20), or from 10–40 seconds post-stimulus (PIPR 30). Using actigraphy, inter-daily stability (IS) was calculated as the amount of overall variability in the recording that is accounted for by the typical 24-hour profile, and reflects stability of the mean 24-h profile day-to-day.

Results

Inter-daily stability (IS) was associated with Net PIPR 20 (Β = 0.561; p = .031) and Net PIPR 30 (Β = 0.551; p = .034; all Β’s are standardized), but not Net PIPR 6 (Β = 0.298; p = .304). Retinal irradiance was calculated for each participant based on age and pupil diameter, to account for age-related differences in transmission of the stimulus to the retina. All raw Net PIPR values were adjusted for calculated retinal irradiance, and gender and time since wake were included as covariates.

Conclusion

Inter-daily stability (IS) values indicate greater stability of 24-hour activity profiles across days. If reduced responsivity to entraining pulses of light is associated with day-to-day instability in activity rhythms, as shown here, we might expect that amplifying entraining light through environmental changes or bright light therapy would normalize inter-daily stability in SAD, or the reverse, stabilizing activity profiles across days could improve depression and/or normalize retinal ipRGC responsivity.

Support

NIMH K.A.R. MH103303
0044 Association Between Chronotype and Circulating Levels of Interleukin-6 in Colorectal Cancer Patients: Preliminary Results from the ColoCare Study
Authors: Peoples A R , Gigic B , Ose J , Himbert C , Hardikar S , Boehm J , Schrotz-King P , Ulrich A B , Schneider M , Li C I , Shibata D , Siegel E M , Figueiredo J C , Toriola A T , Ulrich C M
Published: May 2020

Introduction

Accumulating evidence suggests that chronotype, i.e., circadian topology of an individual indicating morning or evening type, is associated with inflammation. To date, no study has examined the relationship between chronotype and inflammation in colorectal cancer patients. We investigated the associations between chronotype and inflammatory and angiogenesis biomarkers in colorectal cancer patients.

Methods

We used pre-surgery serum samples from n=67 newly diagnosed colorectal cancer patients (stage I-IV) recruited at the ColoCare Study site in Heidelberg, Germany. The ColoCare Study is an ongoing, international, multisite, prospective cohort study in colorectal cancer patients. Inflammatory and angiogenesis biomarkers [c-reactive protein (CRP), interleukin (IL)-6, IL-8, monocyte chemoattractant protein-1 (MCP-1), soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1)] were measured at the Huntsman Cancer Institute, USA using the Meso Scale Discovery platform and were log transformed. Chronotype was assessed prior to surgery with the reduced Morningness-Eveningness Questionnaire (rMEQ; scale 4–25; a higher score indicates more morning-type). Patients were dichotomized, based on the median values for rMEQ, into 2 groups: rMEQ-low (score≤16.0; n=35; indicating more evening-type) or rMEQ-high (score>16.0; n=32; indicating more morning-type).

Results

Using Mann-Whitney U test, we observed that rMEQ-low group (i.e., more evening-type) compared to rMEQ-high group (i.e., more morning-type) had approx. two times significantly higher levels of log transformed IL-6 (mean=2.24 vs. 1.30; U=382.0; Z=-2.23; p=0.03), but not for other inflammatory or angiogenesis biomarkers. This association between chronotype and IL-6 was maintained even after adjusting for age, sex, tumor stage, tumor site, and sleep duration using a generalized estimating equations model (adjusted mean difference=1.10; 95% confidence interval=0.33, 1.88; p=0.01; effect size, Cohen’s d=0.69).

Conclusion

These preliminary findings suggest that the evening chronotype is associated with increased IL-6 inflammatory biomarker in colorectal cancer patients. Further research is needed to confirm and understand the mechanistic underpinnings of the observed results.

Support

Funding: NCI U01 CA206110, R01 CA189184, and R01 CA207371.
0049 Odds Ratio Product as a Measure of Sleep Depth During REM Sleep: Effects on REM Duration and REM Sleep Fragmentation
Authors: Mazzotti D R , Younes M
Published: May 2020

Introduction

The odds ratio product (ORP) is a new highly-validated electroencephalogram biomarker of sleep depth. ORP has been validated as such by several studies investigating the effect of sleep disorders, responses to sleep deprivation and traffic noise. ORP during REM sleep varies considerably among individuals. Whether ORP reflects sleep depth also in REM sleep is unknown. We hypothesized that subjects with high REM ORP are more prone to REM sleep fragmentation.

Methods

Using data from the baseline (SHHS1; N=5,537) and follow-up (SHHS2; N=2,595) visits of the Sleep Heart Health Study, we calculated and summarized ORP in 30-second intervals corresponding to manually scored sleep stage epochs. We developed a heuristic to identify REM periods, defined as sequences of REM sleep epochs separated by no more than 10 minutes of other sleep stages or wake epochs. Using general linear models adjusted by age, sex, body mass index, race and ethnicity, we evaluated the relationship between REM ORP and total REM duration, number of awakening episodes per REM period and arousal index during REM sleep.

Results

Higher REM ORP was correlated with shorter total REM duration (ρ SHHS1=-0.12; p < 0.001, ρ SHHS2=-0.07; p < 0.001), more awakening episodes (ρ SHHS1=0.26; p<0.001, ρ SHHS2=0.30; p < 0.001) and higher arousal index (ρ SHHS1=0.18; p < 0.001, ρ SHHS2=0.16; p < < 0.001) during identified REM periods. In adjusted analyses, one-unit increase in REM ORP was associated, on average, with a 7 minute decrease in total REM duration (β=-7.10; p < 0.001), 1 more awakening episode per REM period (β=1.29; p < 0.001) and an increase of 6 arousals/hour (β=6.16; p < 0.001) during REM sleep periods.

Conclusion

We found that higher REM ORP was associated with shorter REM periods, higher proportion of awake during REM periods and higher REM arousal index. Although small, these differences suggest that ORP is consistent with the concept of sleep depth also during REM sleep.

Support

None
0050 Identification of a Plasma Metabolome-Based Biomarker for Dim-Light Melatonin Offset and Onset in Humans
Authors: Cogswell D T , Bisesi P J , Markwald R R , Cruickshank-Quinn C , Quinn K , McHill A W , Melanson E L , Reisdorph N , Wright K P , Depner C M
Published: May 2020

Introduction

Easily measuring individual circadian timing is increasingly important to inform personalized chronotherapy, screen for circadian disorders and circadian misalignment, and advance circadian research. Findings from multiple studies show that transcriptomics is a viable method to estimate dim-light melatonin onset (DLMO), but no published omics-based findings have predicted dim-light melatonin offset (DLMOff), and only one known study has used metabolomics to predict DLMO. Here, we developed and tested a plasma metabolomics-based biomarker of circadian phase using DLMO and DLMOff as phase markers.

Methods

Sixteen (8M/8F) healthy participants aged 22.4 ± 4.8y (mean ± SD) completed an in-laboratory study with 3 baseline days (9h sleep opportunity/night), followed by a randomized cross-over protocol with 9h sleep and 5h sleep conditions, each lasting 5 days. Blood was collected every 4h on the final 24h of each condition for untargeted metabolomics analyses. DLMO and DLMOff were determined during the final 24h of each condition. Samples from all conditions were randomly split into training (68%) and test (32%) datasets. DLMO and DLMOff models were developed using partial least squares regression in the training dataset and validated in the test dataset.

Results

When validating with the test dataset, R2 for the DLMO model was 0.60, median absolute error (MdAE) was 2.2 ± 2.8h (± interquartile range), and 44% of samples had MdAE under 2h. R2 for the DLMOff model was 0.62, MdAE was 1.8 ± 2.6, and 51% of samples had MdAE under 2h. The DLMOff model predicted baseline samples, under conditions of 9h sleep and controlled food intake, with an R2 of 0.91 and MdAE 1.1 ± 1.1h.

Conclusion

These findings show promise for metabolomics-based biomarkers of circadian phase and highlight the need for biomarker efforts to predict multiple circadian phase markers. Additional analyses with an independent validation dataset will help advance these initial findings.

Support

NIH-R01HL085705, NIH-R01HL109706, NIH-R01HL132150, NIH-K01HL145099, NIH-F32DK111161, and NIH-UL1TR000154; and Sleep Research Society Foundation 011-JP-16;
0058 Effects of Acute Total Sleep Deprivation on Human Plasma N-glycans
Authors: Chatterton B D , Mullington J , Yang H , Haack M , Cummings R , Lehoux S D
Published: May 2020

Introduction

There is a need for a novel biomarker that can be used to measure sleep sufficiency as it pertains to fitness for duty. As glycans (polysaccharides) are known to be involved in modifying protein effectiveness, we are exploring these as biomarkers that may be sensitive to differences between sleep deprivation and normal healthy adult sleep duration. We have measured one major class of glycans, called N-glycans, which are covalently linked to asparagine residues of polypeptide chains of membrane-bound and secreted proteins. We compared the plasma N-glycan profiles of participants before and after they participated in a total sleep deprivation protocol.

Methods

10 healthy participants (6 male, 4 female) aged 30–44 went through 88 hours of total sleep deprivation. Hourly blood draws were taken via forearm catheter throughout the protocol. N-glycan analysis was performed using plasma samples collected at 17:35 prior to the first night of sleep deprivation and at 17:35 following 82.5 hours of continuous wakefulness. N-glycans were first cleaved from peptides and isolated from plasma, and profiles were then measured using Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) mass spectrometry.

Results

66 N-glycans were observed in our profiles. Of these, the relative abundance of 17 N-glycans were significantly different following sleep deprivation (paired t-test, 13 with p<0.05, 4 with p<0.01). In each case, the relative abundance was lower in the sleep deprivation time point. We found two structures, Hex6HexNAc5NeuAc3 and Hex7HexNAc6NeuAc2, which were also significant in one of our previous chronic sleep restriction protocols.

Conclusion

While we observed that many N-glycans decreased in relative abundance, it is unclear whether these changes represent a shift in glycan synthesis or result from decreased expression of the proteins they are bound to. Our next steps involve exploring the functions of the proteins associated with Hex6HexNAc5NeuAc3 and Hex7HexNAc6NeuAc2, and measuring their expression levels.

Support

NIH/HL75501; NIH/National Center for Research Resources UL1-RR02758 and M01-RR01032 to the Harvard Clinical and Translational Science Center.
0065 Initial Findings on Associations Between Sleep and Clinical Measures with Neural Activations Accompanying Fear Conditioning and Extinction in Trauma-Exposed Individuals
Authors: Seo J , Oliver K I , Daffre C , Pace-Schott E F
Published: May 2020

Introduction

We examined associations of sleep and hyperarousal with neural responses to a fear conditioning and extinction protocol in trauma-exposed individuals. We hypothesized, greater hyperarousal, poorer sleep quality and more nightmares would accompany greater activation of the salience network (associated with fear) and lesser activation of the prefrontal cortex (PFC; associated with fear regulation) throughout this protocol.

Methods

Persons exposed to trauma within the past 2 years (N=119, 43 with Post-traumatic stress disorder; PTSD) completed the PTSD Checklist-5 (PCL-5), two weeks of actigraphy and sleep/nightmare diaries, and a 2-day fear-conditioning and extinction protocol during fMRI. Hyperarousal items from PCL-5, sleep quality, and nightmare frequency were used to predict fMRI contrasts representing (1) initial activations to reinforced conditioned stimuli (CS+) during fear conditioning, (2) change in neural activation to CS+s across extinction learning, and, (3) after 24 hours (extinction recall), selective activation to an extinguished (CS+E) versus an un-extinguished CS+.

Results

During fear conditioning, hyperarousal was positively correlated with activation to the CS+ in the right lateral PFC, whereas nightmare frequency was negatively correlated with activations in bilateral orbitofrontal cortex (OFC). Across extinction learning, sleep onset latency (SOL) was negatively correlated with increased activation to CS+ in bilateral insular and dorsal and middle anterior cingulate cortices (salience regions). At extinction recall, nightmare frequency was negatively correlated with selective activation to the CS+E in the left insular cortex.

Conclusion

Except that fewer nightmares predicted greater OFC activation during fear conditioning, results did not support hypothesized relationships of hyperarousal, poor sleep and nightmares with increased salience network and decreased PFC activation to fear-related stimuli.

Support

Funding: R01MH109638
0067 An Anatomic Substrate for GABAergic Processes to Suppress Active Sleep and Promote Wakefulness in the Nucleus Pontis Oralis
Authors: Zhang J , Sampogna S , Xi M , Fung S J , Tobin C , Chase M H
Published: May 2020

Introduction

Our previous electrophysiologic data have provided compelling evidence that GABAergic processes in the nucleus pontis oralis (NPO) play a critical role in the generation and maintenance of wakefulness as well as active (REM) sleep (AS). We therefore hypothesized that one of the neuronal mechanisms of GABA actions in the NPO to promote wakefulness and suppress AS is due to a direct GABAergic inhibition of NPO neurons that generate AS (AS-generator neurons). However, the anatomical substrate for this inhibition is undetermined. Accordingly, the present study was undertaken to examine whether there is any direct interaction between GABAergic neurons and glutamatergic AS-generator neurons in the NPO.

Methods

Adult cats were deeply anesthetized and perfused transcardially. The brainstem containing the NPO was removed, postfixed and cut into 15 μm coronal sections with a Reichert-Jung cryostat. The sections were incubated with a mixture of a rabbit polyclonal antibodies against glutamine and GABA following the procedure of double fluorescence immunohistochemistry.

Results

There was a large number of neuronal somata labeled by anti-glutamine antibody and terminals labeled by anti-GABA antibody in the NPO. These glutamine-positive neurons were medium to large, multipolar cells (> 20 μm), which resemble glutamatergic, AS-generator neurons that have been previously identified in the NPO. Specifically, majority of glutamatergic neuronal somata were closely apposed by multiple GABAergic terminals, indicating that AS-generator neurons in the NPO receive direct GABAergic inputs.

Conclusion

The present results demonstrate that a direct connection exists between glutamatergic AS-generator neurons and GABAergic processes in the NPO. These data provide the anatomical evidence which supports our hypothesis that the pontine GABAergic control of wakefulness and active sleep is partially mediated via GABAergic processes project to NPO AS-generator neurons that suppress the activity of these cells.

Support

NS092383
0074 Inhibitory Neurons in the Dorsomedial Medulla Promote REM Sleep
Authors: Stucynski J , Schott A , Baik J , Hong J , Weber F , Chung S
Published: May 2020

Introduction

The neural circuits controlling rapid eye movement (REM) sleep, and in particular the role of the medulla in regulating this brain state, remains an active area of study. Previous electrophysiological recordings in the dorsomedial medulla (DM) and electrical stimulation experiments suggested an important role of this area in the control of REM sleep. However the identity of the involved neurons and their precise role in REM sleep regulation are still unclear.

Methods

The properties of DM GAD2 neurons in mice were investigated through stereotaxic injection of CRE-dependent viruses in conjunction with implantation of electrodes for electroencephalogram (EEG) and electromyogram (EMG) recordings and optic fibers. Experiments included in vivo calcium imaging (fiber photometry) across sleep and wake states, optogenetic stimulation of cell bodies, chemogenetic excitation and suppression (DREADDs), and connectivity mapping using viral tracing and optogenetics.

Results

Imaging the calcium activity of DM GAD2 neurons in vivo indicates that these neurons are most active during REM sleep. Optogenetic stimulation of DM GAD2 neurons reliably triggered transitions into REM sleep from NREM sleep. Consistent with this, chemogenetic activation of DM GAD2 neurons increased the amount of REM sleep while inhibition suppressed its occurrence and enhanced NREM sleep. Anatomical tracing revealed that DM GAD2 neurons project to several areas involved in sleep / wake regulation including the wake-promoting locus coeruleus (LC) and the REM sleep-suppressing ventrolateral periaquaductal gray (vlPAG). Optogenetic activation of axonal projections from DM to LC, and DM to vlPAG was sufficient to induce REM sleep.

Conclusion

These experiments demonstrate that DM inhibitory neurons expressing GAD2 powerfully promote initiation of REM sleep in mice. These findings further characterize the dorsomedial medulla as a critical structure involved in REM sleep regulation and inform future investigations of the REM sleep circuitry.

Support

R01 HL149133
0080 Daytime Sleepiness Correlates with Increased Gray Matter Volume in the Right Middle Temporal Gyrus in Healthy Young Individuals
Authors: Burns A I , Bullock A , Raikes A C , Dailey N S , Grandner M A , Killgore W D
Published: May 2020

Introduction

Daytime sleepiness has been associated with some neuroimaging metrics, including altered functional connectivity within the default mode network and decreased gray matter volume (GMV) of the medial prefrontal cortex. Most prior studies, however, have focused on patients with sleep disorders or other pathologies. Here we examined the association between GMV and self-reported daytime sleepiness among a healthy group of young adults who reported no sleep-related problems.

Methods

Forty-five healthy adults (22 female; Mean Age=25.4, SD=5.6), who self-reported no history of sleep-related disorders or major medical conditions, completed the Epworth Sleepiness Scale (ESS), the Repeatable Battery for Neuropsychological Status (RBANS) and underwent high-resolution structural neuroimaging at 3T. Gray matter volumes were processed using standard procedures in SPM12. After controlling for age, sex, and intracranial volume, GMV was regressed against ESS scores.

Results

Greater ESS was associated with larger GMV within a cluster of voxels in the right middle temporal gyrus (MNI coordinates: 57, -9, -22; k=1344 voxels, p=.003, FWE cluster corrected). After controlling for ESS scores, larger GMV in this region was associated with poorer delayed memory performance (r=-.345, p=.022) and total neurocognitive performance on the RBANS (r=-.303, p=.046).

Conclusion

Greater daytime sleepiness in healthy normal sleepers was associated with greater GMV within a region of the right middle temporal gyrus. Greater volume of this region was also associated with poorer neuropsychological performance. Decreased GMV of this same region has previously been reported in patients with obstructive sleep apnea and insomnia, suggesting that it may be particularly sensitive to sleep disruption or may play a role in the etiology of sleep disorders, even among young individuals who deny any history of sleep-related dysfunction. Longitudinal work should focus on the potential of this region as a biomarker of vulnerability to sleep problems.

Support
0082 Hippocampal Gray Matter Volume in Healthy Adult Population is Associated with Habitual Sleep Duration
Authors: King R , Jecmen D , Alkozei A , Raikes A C , Grandner M A , Killgore W D
Published: May 2020

Introduction

The hippocampus is well known for its role in sleep and memory consolidation in adolescents, and has been shown to demonstrate neural plasticity and neuronal regeneration. However, the relationship between sleep and hippocampal gray matter volume in healthy adults remains to be fully characterized. We hypothesized that total sleep time (TST), as measured by actigraphy, would correlate positively with gray matter volume (GMV) in the hippocampus, a key memory region of the brain.

Methods

Forty-five healthy normal sleeping adults between 20–45 years of age wore an actigraph for seven days to quantify habitual sleep duration and underwent magnetic resonance imaging during the actigraphy period. Voxel based morphometry in SPM12 was used to estimate GMV at the whole brain level. A region-of-interest mask was used to constrain data analysis to the left and right hippocampi.

Results

Habitual sleep duration per night correlated positively with gray matter volume within part of the left hippocampus (x=-36,y=-20,z=-18; k=32, pFWE-corr=0.093), controlling for age, sex, total intracranial volume, intelligence scores and mood. No correlation was found between TST and hippocampal GMV in the right hippocampus.

Conclusion

Longer sleep time was associated with greater gray matter volume in the left hippocampus. This finding is consistent with what has been observed in healthy children and extend these findings to healthy normal sleeping adults. While TST and GMV are correlated, the causal association cannot be established here. Further research may explore the effects of sleep extension on GMV and how these volume differences associate with various aspects of cognition, particularly memory. It should be noted that this study only included healthy adults with sleep durations between 6–9 hours per night. Future studies would benefit from including adults with a greater variance in their sleep patterns to better understand the relationship between sleep and hippocampal volume, and its potential effects on memory performance.

Support

Defense Advanced Research Projects Agency Young Faculty Award: DARPA-12-12-11-YFA11-FP-029
0096 Future-Relevant Information is Enhanced After Sleep Despite Emotional Salience of Stimuli
Authors: Whitehurst L N , Sattari N , Mednick S C
Published: May 2020

Introduction

A substantial literature supports that sleep biases memory consolidation and retrieval for emotionally-salient stimuli. A smaller, yet growing, literature supports that information deemed relevant to future events may also be favored by sleep consolidation processes. However, it is unclear whether both emotion and predictability would act together to bias sleep-dependent memory formation. Here, we utilized a directed forgetting paradigm with negative and neutral word pairs to examine this open question.

Methods

Sixty young and healthy adults were exposed to word pair stimuli before a polysomnographically-recorded nap. Before the nap, participants were instructed to remember half of the word pairs presented for a later test, and for the other half of word pairs, participants were told to forget them as there would not be a test on them later. Additionally, during encoding, half of the subjects in the sample were exposed to negative valenced, high arousal word pairs while the other half were exposed to neutral, low arousal word pairs. After the nap, subjects were tested on all word pairs presented, regardless of previous instruction. This also included a set of novel word pairs to which participants had not been previously exposed.

Results

A series of 2x2 mixed measures ANOVAs revealed that individuals had better accuracy (p<.001) and fewer misses (p<.001) for the words they were told to remember compared to those they were instructed to forget. Additionally, participants had relatively few false alarms to novel stimuli, 7.14 times, on average (SD=6.10), out of a possible 50 word pairs. Importantly, contrary to predictions, post-nap performance was not dependent on the word pair valence (interaction p’s>.70). No correlations between sleep stages and memory emerged.

Conclusion

These findings suggest that predictability of future events may be a relevant catalyst for sleep-related memory processing.

Support

This work was supported by an Office of Naval Research Young Investigators Award to Sara Mednick and a National Institutes of Mental Health Training grant to Lauren Whitehurst T32MH019391.
1006 Sleep Problems and Risk of Cancer Incidence and Mortality in the Cardiovascular Health Study (CHS)
Authors: Sillah A , Biggs M , Nieto J , Watson N , Gozal D , Peters U , Li C , Thornton T , Phipps A
Published: May 2020

Introduction

Even in the absence of a formal diagnosis, sleep problems (SP) are frequently indicative of an underlying sleep disorder, such as obstructive sleep apnea, which may be adversely associated with cancer risk and cancer outcomes.

Methods

We assessed the association of self-reported SP with incident cancer (N=4,997, excluding prevalent cancers) and cancer mortality (N=5849) among the participants of Cardiovascular Health Study (CHS), a population-based study of adults aged >=65 years recruited from 4 US communities. Participants reported SP (daytime sleepiness, observed apnea and snoring) yearly from 1989-1994; these self-reported symptoms have been validated against objective sleep measures assessed within a subset of CHS participants (n= 1240) who received a home polysomnography as part of the Sleep Heart Health Study. Cancer incidence was ascertained through linkage with state cancer registries through 2005; cancer specific death was adjudicated through 2015. We used Cox proportional hazards regression to calculate hazard ratios (HR) and 95% confidence intervals (CI) for associations of baseline SP with subsequent cancer incidence and cancer mortality, adjusting for baseline sociodemographics, lifestyle factors, and medical history.

Results

The mean age (SD) of the study population was 73 (6) years, 56% were female, and 84% were white. The prevalence of SP was 17% for daytime sleepiness, 8% for observed apnea, and 24% for snoring; 63% reported none of the 3 SP. Overall, 1,130 first incident cancers and 1,014 cancer deaths were identified over median follow-up of 12 and 13 years, respectively. Compared to participants who reported no SP, the risk of incident cancer was inversely associated with daytime sleepiness (HR 0.86 [95% CI 0.70-1.04]), observed apnea (HR 0.74 [0.56-1.00]), and snoring (HR 0.80 [0.68-0.95]). Cancer mortality HR (95% CI) estimates were 1.00 (0.82-1.21) for daytime sleepiness, 0.77 (0.57-1.04) for observed apnea, and 0.88 (0.74, 1.04) for snoring.

Conclusion

Symptoms indicating SP reported at baseline were not associated with increased cancer incidence or cancer mortality. Ongoing analyses are focused on the impact of longitudinal SP (time dependent, cumulative average) to ensure an adequate latency period is incorporated into our analysis of the association between SP and cancer risk and mortality.

Support

NIHT32CA09488017
1014 Relationship Between Lung Function and Obstructive Sleep Apnea in Cystic Fibrosis
Authors: Shakkottai A , Nasr S Z , Hassan F , O’Brien L M , Chervin R D
Published: May 2020

Introduction

The frequency of obstructive sleep apnea (OSA) may be high among patients with cystic fibrosis (CF), a life-shortening, genetic respiratory disease that affects approximately 30,000 Americans. Yet, the potential relationship between OSA and lung function has not been thoroughly explored.

Methods

Single-center retrospective review of polysomnography (PSG) results from 2009-2017 in referred patients with CF and available pulmonary function data (PFTs) obtained at time of PSG and at 3, 6, 9, and 12-months prior.

Results

Mean ages were 11.1±3.9 (sd) and 37.1±14.1 years, among 18 children and 16 adults, respectively. Mean body mass index (BMI) was normal in both groups (62.5±26.6% in children; 25.1±6.4 kg/m2 in adults). Twenty-six subjects (76%) had OSA (apnea-hypopnea index >1 in children, ≥5 in adults). Mean forced expiratory volume in 1 second percent predicted (FEV1 PPD) was higher among subjects with vs. without OSA at PSG and at each time-point in the year prior, independent of age and BMI at PSG (longitudinal mixed effects model, β=19.0, SE=8.1, p=0.028). While FEV1 PPD remained unchanged in the non-OSA group, FEV1 PPD at PSG was lower, in comparison to the year prior in subjects with OSA, with the greatest difference observed at 9-months prior to PSG (2-sample t-test, difference of -6.6% vs 0.6% in OSA vs. non-OSA groups respectively, p=0.078).

Conclusion

The PFTs, as daytime markers of CF lung disease severity, do not seem to reliably predict risk for OSA. In our sample, CF patients with vs. without OSA had better PFTs at baseline but they also showed a greater tendency for decline in PFTs over the year prior to OSA diagnosis. Larger sample size and longer duration of assessment may help, going forward, to assess any potential adverse impact of OSA on lung function decline.

Support

NIH Training Grant (T32NS007222, F32HL145915)
1020 Sleep and Glycemic Control in Adults With Long-Standing Type 1 Diabetes and Hypoglycemia Unawareness
Authors: Malone S K , Peleckis A J , Pack A I , Perez N , Yu G , Rickels M R , Goel N
Published: May 2020

Introduction

Nocturnal hypoglycemia is life threatening for individuals with type 1 diabetes (T1D) due to loss of hypoglycemia symptom recognition (hypoglycemia unawareness) and impaired glucose counterregulation. These individuals also show disturbed sleep, which may result from glycemic dysregulation. Whether use of a hybrid closed loop (HCL) insulin delivery system with integrated continuous glucose monitoring (CGM) designed for improving glycemic control, relates to better sleep across time in this population remains unknown.

Methods

Six adults (median age=58y,T1D duration=41y) participated in an 18-month ongoing clinical trial assessing the effectiveness of an HCL system. Sleep and glycemic control were measured concurrently using wrist actigraphs and CGM at baseline (1 week) and months 3 and 6 (3 weeks) following HCL initiation. BMI and hemoglobin A1c (HbA1c) were collected at all timepoints. Spearman’s correlations modeled associations between sleep, BMI, and glycemic control at each time point. Repeated ANOVAs modeled sleep and glycemic control changes from baseline to 3 months and to 6 months.

Results

Sleep and glycemic control indices showed significant associations at baseline and 3 months. More time-in-bed and later sleep offset related to higher HbA1c levels at baseline. Later sleep onset, midpoint and offset, and greater sleep efficiency associated with greater %time with hyperglycemia (glucose >180 mg/dL) or hypoglycemia (glucose <70 mg/dL) at baseline and 3 months. Longer sleep duration and greater sleep efficiency related to greater %time with hyperglycemia at 3 months. At 3 months, more wake after sleep onset associated with lower HbA1c levels and longer nocturnal awakenings and more sleep fragmentation associated with less glycemic variability. While both sleep and glycemic control improved from baseline to 3 and 6 months, these were not statistically significant.

Conclusion

Various dimensions of actigraphic sleep related to concurrently estimated glycemic indices indicative of poorer glycemic control and HbA1c across time in adults with long-standing T1D and hypoglycemia unawareness.

Support

This work was supported by NIH R01DK117488 (NG), R01DK091331 (MRR), and K99NR017416 (SKM).
1021 Effect of Dietary Nitrate Supplementation on Sleep in Chronic Obstructive Pulmonary Disease Patients
Authors: Wisor J P , Holmedahl N , West Saxvig I , Fjeldstad O , Weitzberg E , Gronli J , Engen H
Published: May 2020

Introduction

Chronic obstructive pulmonary disease (COPD) requires the use of accessory muscles to overcome inadequate ventilation. The activity of these voluntary muscles is compromised during sleep, resulting in insufficient ventilation, oxygen desaturation and disruption of sleep. Nitrate supplementation with dietary beetroot juice (DBJ) is known to increase the efficiency of oxygen utilization in non-COPD individuals; its therapeutic effect in COPD is uncertain.

Methods

In a repeated measured experiment involving 15 COPD patients, subjects consumed either 70 mL of beetroot juice containing nitrate (~6.2 mmol NO3-) or placebo (NO3--depleted juice) immediately before bedtime. Sleep states were defined based on F4-O2 electroencephalogram and masseter electromyogram. All subjects spent at least 6.2 hrs in bed; the data analysis was therefore restricted to the first 6 hrs in bed.

Results

Standard polysomnography indicated no changes in the amount of time spent in any sleep stages. Wake-to-N2 transitions were greater than two-fold more frequent after placebo (a total of 21 observed) than DBJ (9 observed), resulting in a significant main effect of treatment (F1,14=7.3, P=0.017). N2-to-wake transitions were nearly 3-fold more frequent after placebo (a total of 35 observed) than DBJ (12 observed), resulting in a significant main effect of treatment (F1,14=2.52, P=0.024). Direct wake-to-REMS transitions were observed four times after placebo and never after DBJ (F1,14=2.26, P=0.041). DBJ also resulted in sustained elevation of peripheral oxygen saturation (SpO2), measured by pulse oximetry, during episodes of wake after sleep onset (WASO). Two minutes into WASO after DBJ SpO2 was elevated by 1.09 + 0.31% relative to pre-WASO; two minutes into WASO after placebo SpO2 was elevated by 0.08 + 0.54% relative to pre-WASO (P=0.012).

Conclusion

Collectively, the reduced frequency of atypical transitions after DBJ are indicative of an improvement of sleep quality. DBJ is thus a potential adjunct therapy for disordered sleep in COPD.

Support

N/A