Journal of Circadian Rhythms最新文献

Introduction: Sleep plays a vital role in maintaining overall health, supporting processes like restoration, memory consolidation, emotional regulation, and metabolism. However, many people remain unaware of their sleep needs, leading to poor sleep quality and patterns that can negatively impact health, workplace performance, and daily life. Sleep behaviors are shaped by various factors, including cultural practices, urbanization, and lifestyle changes. This study focuses on adults in Karachi, Pakistan, where religious routines and modern living create unique sleep challenges. By exploring these patterns, we aim to identify ways to enhance sleep quality and promote better well-being in this population.

Methodology: This cross-sectional study was conducted in Karachi, Pakistan, over one year, with 400 adults aged 18-64 were recruited. Exclusion criteria included conditions affecting sleep, chronic illnesses, and use of sleep aids. Data collection employed a Google Forms-based structured questionnaire covering demographics, religious practices, and sleep habits. Sleep quality and daytime sleepiness were assessed using the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS), respectively. Data analysis, performed in SPSS, included descriptive statistics and hypothesis testing using Chi-squared, Mann-Whitney, and Kruskal-Wallis tests. Sleep patterns were categorized as monophasic, biphasic, or polyphasic using conditional formulas in Excel.

Results: The mean age of participants (n = 384) was 29 ± 0.1 years, with 66.4% women. The most common sleep pattern was monophasic (40.4%), followed by biphasic-siesta (21.6%), biphasic-dawn (20.8%), and polyphasic (17.2%). Women favored segmented sleep patterns (p = 0.019). Biphasic-dawn sleepers reported the least daytime sleepiness (ESS = 7.18 ± 3.85, p = 0.024), while biphasic-siesta sleepers had the poorest sleep quality (PSQI = 6.94 ± 3.01, p = 0.013). Men had better sleep quality (PSQI = 5.22 ± 2.70) and lower daytime sleepiness (ESS = 6.89 ± 3.65) than women (p < 0.001). Weekend sleep disruptions were significant (p < 0.001).

Conclusions: Monophasic sleep dominates, though gender differences suggest women prefer segmented patterns. Biphasic-dawn sleep aligns with better quality and less daytime sleepiness, while biphasic-siesta sleepers experience the poorest outcomes. Men and employed individuals generally report better sleep metrics. Morning prayers improve sleep quality slightly. Students exhibit higher daytime sleepiness and worse sleep quality compared to others.

The hypothalamic suprachiasmatic nucleus (SCN), the circadian pacemaker of the mammalian brain, integrates both environmental and endogenous information to modulate various physiological and behavioral processes. Both light and physical activity entrain SCN circadian rhythmicity, but the underlying molecular mechanisms for physical activity remain elusive. Repetitive neuronal stimulation results in accumulation of the stable transcription factor ΔFOSB, that has been implicated in long-term brain plasticity, altered neuronal excitability, and changes in behavior. In rodents, voluntary wheel running (VWR) mimics aspects of exercise training and increases ΔFOSB in several brain regions. Whether VWR also alters ΔFOSB in the SCN is unexplored. Here, young-adult male and female Wistar rats were housed sedentary or allowed to run for four weeks followed by quantification of ΔFOSB in the SCN. VWR lowered SCN ΔFOSB-positive cell numbers in males and females compared to sedentary housing. Total running distance did not correlate with ΔFOSB suppression. Analysis taking estrous cycle into account revealed that ΔFOSB-positive cell numbers were cyclic in sedentary females, being lowest during proestrus and highest during diestrus. Remarkably, this cyclicity was absent in runners, where ΔFOSB-positive cell numbers remained comparable to those observed during proestrus in sedentary controls. Finally, estradiol replacement following ovariectomy in sedentary females lowered SCN ΔFOSB-positive cell numbers. Thus, VWR and estrous cycle, via, at least in part, estradiol, modulate SCN ΔFOSB. Given its role in long-term plasticity and behavioral adaptations, ΔFOSB may provide a molecular link between VWR and/or estrous cycle and the output of the SCN and its related behavioral adaptations.

8-hydroxy-2'deoxyguanosine (8-OHdG) is an oxidative product removed from DNA following radical oxygen species-induced damage. As a water-soluble molecule, it can be measured non-invasively in urine and is commonly used as a marker for 'whole-body' oxidative stress. However, its validity and reliability in assessing oxidative stress across various chronic diseases and in early carcinogenesis screening in clinical diagnosis and research remain subjects of debate. To determine optimal measurement timing and duration, it is essential to establish the circadian profile of 8-OHdG under everyday life conditions. Here, applying the integrative single-case design, we show the presence of day-night differences for 8-OHdG in continuous time series of two breast cancer survivors while considering different correction approaches. The participants sampled their urine in 12-h-pooled collections over one month. In both subjects, 8-OHdG levels were significantly higher during the day than at night regardless of whether they were corrected by creatinine or urine volume (creatinine corrected: t = -6.43, p < 0.01 [subject 1], t = -2.69, p = 0.01 [subject 2]; volume corrected: t = -7.30, p < 0.01 [subject 1], t = -3.69, p < 0.01 [subject 2]). Notably, urinary 8-OHdG levels show higher variability in night samples compared to day samples. These findings underscore the importance of considering daily fluctuations in 8-OHdG levels in both clinical and research studies, as well as the need to account for the dynamic characteristics of stress markers to minimize the risk of inconsistent or misleading results in clinical diagnostics.

Introduction: Circadian processes may be causal in the development and maintenance of binge eating. We used a rodent model of binge-like eating and a circadian disruption protocol to test whether circadian disruption causes increased consumption during 24h access to a high energy diet (HED).

Method: Eight male mice underwent a two-week baseline with ad-lib standard chow and maintained a 12h light-dark schedule. Mice then completed two binge cycles. After, mice received a circadian disruption manipulation or remained on typical light schedule (i.e., were non-circadian disrupted). All mice received two binge cycles after manipulation. Chow and HED were measured every 12h and 24h. Independent samples t-tests compared consumption between the disrupted and non-disrupted groups.

Results: Binge-like eating occurred in both experimental groups across all phases of the study. Circadian disrupted mice consumed more during HED access than non-disrupted mice, indicating that circadian disruptions may exacerbate binge-like eating. Circadian disruption also altered consumption timing; disrupted mice consumed more during typical rest hours (7:00-19:00) than non-disrupted mice but did not alter consumption during typical active hours (19:00-7:00).

Conclusions: These results provide justification for research examining circadian processes implicated in binge eating. Future research may inform on the utility of circadian regulating adjunctive treatment (e.g., bright light therapy or exercise).

The anterior region of the hypothalamus accommodates a bilateral structure called the suprachiasmatic nucleus (SCN), which controls, modulates, and perpetuates the homeostasis of circadian rhythm and sleep hormone release. These SCN have a predominance over multitudinous peripheral tissues like the uterus, liver, intestine, pancreas, endocrine system, immune system, reproductive system, and cardiovascular system. This peripheral clock acts as a pacemaker for circadian rhythm timing, which regulates crucial metabolic pathways and organizes numerous activities in the female reproductive network of mammals. The circadian CLOCK genes are expressed in various reproductive organs. The CLOCK, BMAL1, CRY, and PER genes harmonize the balance and manifestation of nuclear receptors (NRs) expression, and the other way round, NRs regulate these circadian genes. Several NRs, in particular estrogen, progesterone, androgen, and PPARs, nurture the ovary and uterus. Bidirectional coordination between SCN and NRs maintains the circadian rhythm of the hypothalamic-pituitary-gonadal (HPG) axis of the female reproductive organs.

Morningness is associated with several positive health outcomes and personality traits such as conscientiousness. In the current report, meta-analysis demonstrated a significant association between morningness and conscientiousness, data that are consistent with previous meta-analyses. Further, survey report and resting-state functional Magnetic Resonance Imaging (rs-fMRI, N = 43) indicated that the relationship between morningness and conscientiousness was moderated by functional connectivity with the Default Mode Network (DMN). DMN connectivity has been implicated in a number of cognitive functions and higher connectivity in this network is associated with higher conscientiousness.

The influence of morningness-eveningness preference and dietary components on the circadian variation in peak expiratory flow (PEF), an established criterion for pulmonary function, is not fully understood. This study aimed to investigate (a) how the chronotype influences the 24-h variation in PEF and (b) whether the bronchodilator theobromine affects this variation differently in different chronotypes. Ninety-seven healthy non-smoking females (54 early chronotypes, ET; 43 late chronotypes, LT; 18-35 years) recorded their PEF over 24 hours at 4-h intervals (08:00/12:00/16:00/20:00/24:00/04:00/08:00 h). In a subgroup (26 ET, 18 LT), the effect of 48 mg theobromine (40 g dark chocolate) on PEF was compared on three consecutive 24-h days with no administration, morning administration and evening administration of theobromine. Repeated measures ANOVA tested for 24-h variation in PEF. Both chronotypes displayed significant 24-h variation in PEF (P < 0.0001) explaining 36% (ET) and 31% (LT) of variance of PEF. The time of maximum PEF was three hours earlier in ET than in LT (P = 0.003) and correlated negatively with chronotype scores (P = 0.001) and positively with bedtimes (awakening time: P < 0.001; sleep-onset time: P = 0.012). The chronotypes showed no differences in 24-h mean and amplitude % mean for PEF. Administration of theobromine strengthened the morning increase (P = 0.004) and weakened the evening decrease (P = 0.063) of PEF in LT, but had no effect in ET. The differences found between chronotypes in timing of maximum PEF and responsiveness to the bronchodilator theobromine might have clinical relevance. Therapy for respiratory diseases should consider the chronotype of patients for drug timing and dosage.

Sleep disturbance is common following acute coronary syndrome (ACS) and may contribute to a worse prognosis. We describe the rationale, design, and findings of a pilot and feasibility randomized clinical trial (RCT) of an intervention to improve post-ACS sleep. Fifteen post-ACS patients with insomnia and/or short sleep were randomized (2:1 allocation) to combined chronotherapy (CC) plus sleep hygiene education (SHE) or SHE control. CC was bright light therapy (BLT) delivered by a wearable light visor for 30 minutes after awakening and short-wavelength light avoidance using blue-light blocking (BLB) glasses in the evening from 8:00pm to bedtime daily for 4 weeks. Primary outcomes were feasibility, acceptability, appropriateness, usability, and adherence. Secondary outcomes were insomnia symptoms, sleep quality, and sleep duration. Two patients in the CC intervention group dropped before initiating study procedures. Completion of study procedures in remaining patients was high in the CC and control groups (88% and 100%, respectively). Self-reported adherence to CC (i.e., using BLT and BLB on ≥50% of days) was high (88% and 100%, respectively). The proportion of CC patients who perceived the intervention as feasible (71%) and usable (100%) was high, though fewer CC patients rated the intervention as acceptable (57%) and appropriate to improve sleep (29%). Improvements in insomnia symptoms and self-reported sleep quality and duration were seen in response to the CC intervention (71%). Post-ACS patients with sleep disturbance had high adherence to this chronotherapeutic intervention, and most viewed it as feasible and usable. This intervention should be tested in a larger RCT to determine efficacy to improve sleep.

Trial registration: ClinicalTrials.gov number NCT05299723.

Date of registration: March 29, 2022.

Url of trial registry record: https://classic.clinicaltrials.gov/ct2/show/NCT05299723.

The developmental origins of health and disease theory suggests that environmental exposures during early life, particularly during prenatal life, can greatly influence health status later in life. Irregular light-dark cycles, such as those experienced during shift work, result in the repeated disruption of circadian rhythms, which negatively impacts physiological and behavioral cycles. The purpose of our study was to assess parameters in the developing mouse embryo and fetus using high frequency ultrasound when exposed to circadian disruption. Pregnant female mice were subjected to a seven-hour advanced circadian disrupted protocol or remained on a normal 12/12 light-dark cycle throughout pregnancy. Significant differences were observed in placental length (p = 0.00016), placental thickness (p = 0.0332), and stomach diameter (p = 0.0186) at E14.5-18.5. These findings suggest that circadian disruption in pregnant dams, mimicking shift work, alters embryonic and fetal development in specific organs in utero.

Background: Stroke patients often present circadian disruption due to multiple causes e.g., primary disease, comorbidities, medication, immobilization, reduced daylight entrainment and sleep disturbances.

Objective: To investigate the circadian rhythm of temperature in forehead skin in patients with moderate to severe stroke admitted for rehabilitation.

Methods: A physiologic study in form of a secondary analysis of a former randomized study. In total 27 patients with moderate to severe stroke were included between May 1^st 2014, and June 1^st 2015. Circadian temperature was collected approx. seven days after admission at the acute stroke unit by a skin surface temperature probe as part of a Polysomnography (PSG) measurement.

Results: Temperature variations show no circadian rhythm (Type 3 tests of fixed effects by SAS, p = 0.1610). The median temperature variance did fluctuate, but not significantly, and the small changes in circadian temperature variance did not follow the normal temperature variance.

Conclusion: Patients with moderate to severe stroke show an abrogated circadian rhythm of temperature. There is an unmet need to understand the mechanisms for this, significance for stroke outcome and treatment.