Circadian Misalignment Leads to Changes in Cortisol Rhythms, Blood Biochemical Variables and Serum miRNA Profiles

Abstract

Background: Circadian clock plays a critical role in synchronizing the inner molecular, metabolic and physiological processes to the environmental cues which cycle with a period of 24 h. Misalignment in the circadian rhythms leads to decrease in adaptation, performance and increased risk of associated disorders. The non-24-h schedules and shift schedules are commonly used in maritime operations, both of which could result in disturbance in circadian rhythms. The comprehensive effects of these schedules remain to be further elucidated.Methods: In this study, we firstly conducted an experiment in which the volunteers followed a 3-d rotary schedule with consecutive shift in sleep time (rotatory schedule), and analyzed the changes in salivary cortisol rhythms and blood variables. Next we conducted another experiment in which the volunteers followed an 8 h on and 4 h off schedule (non-24-h schedule) to compare the changes in blood/serum variables. Furthermore, the plasma miRNAs from the volunteers following the rotatory schedule were subject for miRNA sequencing. Results: The rotatory schedule led to elevated levels of serum cortisol during the early stage, and the phase became delayed during the early and stages. The results show both of the schedules caused comprehensive changes in blood/serum biochemical variable, and consistently, the increase in phosphate levels. In addition, a subset of serum miRNAs targeting genes involved in circadian rhythms, sleep homeostasis and multiple important physiological processes or pathways were identified in the experiment with rotatory schedule.Conclusions: This study revealed an increased stress during the rotatory schedule. Circadian misalignment caused by either non-24-h or rotatory schedule lead to extensive changes in blood/serum variables. As to the rotatory schedule, altered expression of serum miRNAs may account for the consequences of circadian misalignment. These findings would help understand the deleterious effects of shift schedules and optimize to enhance performance and welfare of the personnel working with similar schedules.

Associations between circadian misalignment and telomere length in BD: an actigraphy study

“…Both tobacco and alcohol use have been associated with shorter TL in metaanalyses (Astuti et al 2017;Navarro-Mateu et al 2021). Moreover, circadian misalignment may lead to circadian disturbances in cortisol secretion rhythms (Huang et al 2021) and, in turn, cortisol reactivity has been associated with telomere shortening (Jiang et al 2019).…”