Chronobiology International最新文献

The circadian clock, an endogenous timekeeping system governed by core genes such as BMAL1, CLOCK, PER, and CRY, regulates physiological processes critical to thyroid function. Disruption of circadian rhythms (resulting, for example, from shift work and/or exposure to artificial light at night) has emerged as a significant risk factor for thyroid carcinogenesis. This review elucidates the dual role of circadian rhythms in maintaining thyroid homeostasis and their mechanistic contributions to cancer initiation, progression, and therapy resistance. We highlight molecular pathways linking clock dysregulation to oncogenic signaling, immune evasion, and metabolic reprogramming, while proposing chronotherapy as a novel precision oncology strategy.

Disruption of social and circadian rhythms (SCRs) is linked to the pathophysiology and course of bipolar disorder (BD). Valproate response in BD is variable and may be influenced by SCRs and genetic polymorphisms. This study investigated the relationship of valproate response with COMT (rs4680), CLOCK (rs1801260), GSK3-ß (rs334558) polymorphisms, SCRs, and chronotype. Ninety-four subjects with BD in remission and under valproate treatment were enrolled. Rhythm was evaluated with the Social Rhythm Metric-5 (SRM-5), the Biological Rhythm Interview for Assessment in Neuropsychiatry (BRIAN), and the Morningness Eveningness Questionnaire. Valproate response was measured with the Alda Scale. Genotyping was detected using PCR-RFLP, and serum valproate levels were measured 12 h after the last dose. In GSK3-ß, the C/T genotype showed lower partial response rate (p = 0.02), and C allele was present in all evening chronotypes (p = 0.06). In COMT, A allele carriers had greater deviation in first social interaction (p = 0.04), and the A/A genotype had higher complete response rates than the A/G (p = 0.03). In CLOCK, C allele carriers had a later age of onset (p = 0.01), fewer previous depressive (p = 0.05) and manic/hypomanic (p = 0.02) episodes, lower BRIAN total (p = 0.01) and social subscale scores (p = 0.01), and lower SRM-5 weekly mood swing score (MSS) (p = 0.03). All evening chronotypes were non-C allele carriers (p = 0.06). Valproate response was predicted by a model including duration of illness, HDRS total score, number of previous manic/hypomanic episodes, SRM-5 weekly MSS, duration of valproate exposure, and presence of the A allele in COMT polymorphism (R² = 0.31, p < 0.001). These results highlight the value of integrating genetic and SCRs factors into personalized BD treatment.

Many organisms are sensitive to lunar cycle-related changes, such as tidal fluctuations and variations in moonlight intensity. Marine organisms must synchronize their behavior to the underwater environment, which is more complex and variable than terrestrial habitats. Lunar-synchronized spawning refers to the monthly spawning cycle triggered by changes in phase of the moon and is especially common among temperate and tropical marine species. Corals, marine worms, and fish are well-known examples of organisms that spawn synchronously with lunar phases to improve fertilization success. Research over the past decade has provided insights into lunar-synchronized spawning, and studies of families such as Siganidae and Serranidae have begun to elucidate the underlying mechanisms in fish. Field investigations, particularly in tropical and subtropical waters, have shown that many species spawn during periods of the new or full moon. Species-specific spawning times may be determined genetically, with long-term environmental adaptation influenced by physicochemical and ecological factors. Even within the same species, spawning moon phases can vary by location. As lunar-synchronized spawning is regulated by moonlight cues, these geographical differences are likely driven by genetic variation in photoresponsiveness. Physiological experiments have further suggested that nocturnal light plays a role in both gonadal development and the timing of spawning in fish. Fish have been hypothesized to be able to predict moon phases for spawning by detecting temporal changes in moonlight intensity associated with the lunar cycle.

Little is known about the relationship between sleep quality and quantity associated with mood, fitness, and menstrual cycle status in elite athletes. This longitudinal prospective cohort study explores these relationships in a French cohort of elite athletes in preparation for the Olympic Games. Self-reported sleep patterns, quality, mood, fitness and menstrual cycles were monitored daily via smartphone applications from February 2021 to February 2024, involving 108 athletes and 13 852 observations. Generalized Estimating Equations were used to evaluate associations between these variables across three menstrual cycle status groups (i.e regular, irregular, or under hormonal contraception). Sleep duration significantly correlated with self-reported sleep quality (β = 0.179), fitness (β = 0.241), and mood (β = 0.097) across all menstrual cycle status groups. Sleeping less than 8 h led to below-average scores in these parameters. Late bedtimes, especially after 11 PM for athletes with irregular cycles and after midnight for all groups, negatively impacted sleep quality, fitness, and mood. Athletes using hormonal contraception reported slightly longer sleep durations than those with regular (p < 0.04) or irregular cycles (p < 0.02). Despite individual variations, the cohort's average sleep duration (8.5 ± 1.2 h) aligned with recommended guidelines. Sleep patterns significantly influence mood and fitness similarly among elite athletes with a regular or irregular menstrual cycle or under hormonal contraception. Further studies are needed to clarify the role of hormonal status in sleep and its long-term implications for athlete health.

         The daily melatonin rhythms and the effect of light pulse on this hormone were evaluated for Amazonian fish, Astronotus ocellatus and Brycon amazonicus. In experiment 1, fish were exposed to a 12h light:12h dark, and blood was sampled every 4h. In experiment 2, a light pulse was provided in the middle of the dark period for 1h. Melatonin peaked in the middle of the dark period in both species, and both showed an inverted ocular rhythm. The light pulse reduced plasma melatonin to daytime levels, while ocular melatonin remained unchanged. Thus, photic stimulation can be used as a physiological time cue.

Ghrelin is a peptide hormone that plays a central role in short-term appetite regulation and energy balance. Its secretion is not only influenced by nutritional status but also shaped by circadian rhythms and habitual eating patterns. Ghrelin levels typically rise during fasting and decrease after meals, but they also follow a daily rhythm, peaking during the night and reaching their lowest levels in the morning. Human studies suggest that consistent meal schedules may entrain ghrelin secretion, with anticipatory rises occurring before habitual mealtimes. Experimental interventions show that morning-loaded eating patterns, compared to evening-loaded ones, lead to stronger postprandial ghrelin suppression, enhanced satiety hormone responses, and greater weight loss, even with similar caloric intake. In contrast, delayed or misaligned eating, such as during night-shift work, is associated with elevated ghrelin levels at biologically inappropriate times and increased hunger. Some studies have also highlighted the leptin-to-ghrelin ratio as a useful marker of appetite regulation and metabolic risk, particularly in overweight individuals. Together, these findings support the idea that the timing of food intake modulates ghrelin dynamics and influences metabolic outcomes. Meal timing, when aligned with endogenous biological rhythms, may therefore serve as a practical target for chrononutritional strategies aimed at improving appetite control and weight regulation.

Circadian rhythms, typically synchronized with light-dark cycles, regulate key biological processes in surface organisms. In caves, however, the absence of light may disrupt these rhythms or promote alternative temporal patterns. We examined locomotor activity in two cave-dwelling scorpions with contrasting degrees of subterranean adaptation: Troglorhopalurus translucidus (troglobitic) and Troglorhopalurus lacrau (troglophilic). Activity was monitored under constant darkness (DD), light-dark (LD), and constant light (LL). Both species retained circadian rhythmicity, but with distinct responses: T. translucidus and T. lacrau exhibited diurnal activity under LD and changes in period under DD and LL. These findings demonstrate that circadian regulation persists in cave-adapted scorpions, but its expression is shaped by evolutionary pressures, highlighting the plasticity of biological clocks in light-deprived environments.

The aim of this study was to investigate the effect of circadian rhythmicity (CR) on lower extremity strength and balance performance in 22 female athletes (19-24 y). Participants underwent isokinetic knee strength, Single Leg Hop Tests (SLHT), Y Balance Test (YBT), and isokinetic static/dynamic balance tests. All measurements were randomized and performed at 9:00, 14:00, and 19:00 to assess CR variation. In total, 3 angular strength, 5 jump, and 2 balance tests were analyzed. When comparing results across time zones, body temperature, isokinetic 60°/sec extension (Ext) strength, and several bipedal static balance parameters Forward-Backward Standard Deviation (SBFD), Average Forward-Backward Speed (AFBS), and Ellipse Area (EA)) showed statistical significance (p>0.05). No significant differences were found in other isokinetic strength tests, all SLHTs, Y balance, or dynamic balance tests (p>0.05). Significant CR effects on lower extremity strength were observed only in the 60 sec extension, with overall strength peaking at 14:00. Strength asymmetry remained similar across time points. These findings suggest that time-sensitive performance parameters like strength and static balance are influenced by CR, while balance and coordination parameters appear more stable. Accordingly, scheduling strength-based training during midday hours may optimize performance by leveraging CR-related variations.

Fatigue is a known contributor to maritime accidents, with roster patterns, shift schedules, and job roles identified as key risk factors in long-distance shipping. This exploratory study investigates whether similar patterns exist in ferry operations. Sixty-three UK ferry workers participated in a field study involving at least 2 weeks of on-duty data collection. Participants wore activity monitors and completed sleep diaries and 9-point scale ratings of sleepiness (KSS), stress, and workload. The sample included four roster types, three work schedules, and six job roles; 52% slept onboard, while others returned home between shifts. Sleepiness on duty (KSS ≥ 7) was reported in 27% of shifts. The shortest sleep was observed in participants working 12-h split shifts and 8 weeks on/4 weeks off rosters. However, the greatest number of shifts with KSS ≥ 7 were found in workers on 2 weeks on/2 weeks off and 1 week on/1 week off rosters. Bridge crew reported the most stress, and service crew the highest workload. Sleep location (onboard vs. home) did not significantly affect outcomes. Fatigue was widespread across roles and schedules, suggesting that mitigation strategies should target the entire workforce. Split shifts should be avoided, and current regulations are insufficient to manage fatigue effectively.

Circadian rhythm sleep-wake disorders (CRSWD) are characterized by misalignment between the sleep-wake rhythm and the environmental day-night cycle, leading to disturbances in daily life. Melatonin and light therapy targeting circadian rhythms are generally used, but with limited efficacy. Recent studies have revealed that one-third or more of CRSWD patients with abnormal sleep-wake rhythm have normal melatonin rhythm, indicating the possible involvement of internal desynchronization, where circadian rhythm and sleep-wake rhythm dissociate. Aripiprazole (APZ) is a dopamine D2/D3 receptor partial agonist and has recently been shown effective to CRSWD. In this study, we explored the potential of APZ in treating mouse model of CRSWD. We use male C57/Black6 mice and first demonstrated APZ administered to the mice with normal sleep-wake rhythm increased sleep during the rest period and also increased wakefulness during the next active period. We next found APZ administered to the chronic methamphetamine (MAP)-treated mice with CRSWD like sleep phenotype synchronized their sleep-wake rhythm to the light-dark cycle. This entrainment was also accompanied by changes in sleep architecture. These findings brought insights into the mechanism how APZ acts on patients with CRSWD, especially with internal desynchronization.