Circadian Rhythm Disturbance in Acute Ischemic Stroke Patients and Its Effect on Prognosis

Study on the Mechanisms of Ischemic Stroke Impacting Sleep Homeostasis and Circadian Rhythms in Rats

OBJECTIVE

This study aimed to investigate the impact of ischemic stroke (IS) on sleep homeostasis and circadian rhythms in rats, as well as the underlying mechanisms.

METHODS

The middle cerebral artery occlusion model was employed to induce IS in rats. Sixty young and sixty aged rats were randomly divided into six groups for experiments. Neurological function was assessed using the Garcia score, and infarct size was evaluated through 2,3,5-triphenyltetrazolium chloride staining. Sleep-wake cycles were monitored by implanting electrodes into the neck muscles to record electroencephalograms and electromyograms. Parameters such as sleep latency, waking time, non-rapid eye movement (NREM) sleeping, rapid eye movement sleeping, NREM delta power, and waking theta power were measured. Serum cortisol and melatonin levels were measured using enzyme-linked immunosorbent assay. Gene and protein expression of circadian regulators period 1 (Per1) and cryptochrome 1 (Cry1) in the pineal gland were assessed using real-time quantitative reverse transcription polymerase chain reaction and western blot.

RESULTS

Compared to the sham groups, IS-induced rats showed a decrease in Garcia scores and an increase in cerebral infarction area. Besides, relative to young rats, aged rats exhibited more severe cerebral infraction damage, lower melatonin levels, higher cortisol levels, disrupted sleep-wake cycles, and altered gene and protein expression levels of Per1 and Cry1 in the pineal gland.

CONCLUSIONS

IS can lead to neurological impairments and brain damage, with aged rats showing more severe effects. IS also disturbs melatonin and cortisol levels, affects sleep homeostasis, and results in disordered Per1 and Cry1 gene and protein expression levels. These findings underscore the role of circadian disruption and stress response in the pathology of IS, especially in aging populations.

Variability in sleep architecture and alterations in circadian rhythms in patients with acute cerebral infarction accompanied by sleep-disordered breathing

PURPOSE

To continuously and dynamically monitor the sleep status of patients in the acute phase of cerebral infarction, and to investigate the characteristics of acute cerebral infarction(ACI)associated with sleep-disordered breathing (SDB), variations in sleep structure, and changes in sleep circadian rhythms.

METHODS

Patients with ACI within 48 h of onset who were admitted to the Department of Neurology at Kailuan General Hospital from November 2020 to December 2022 were selected. Detailed baseline information such as age, gender, smoking history, drinking history, were recorded for the selected participants. From the beginning of their hospitalization, the selected participants were monitored for their sleep status continuously for 5 days using the Intelligent Mattress-based Sleep Monitoring Platform System(IMSMPS). Based on the heart rate data obtained from the monitoring, the interdaily stability (IS) and intradaily variability (IV) of the sleep circadian rhythm were calculated.

RESULTS

1,367 patients with ACI were selected. Monitoring results over 5 days indicated 147 cases (10.75%) without SDB, and 1,220 cases (89.25%) with SDB. Among the group with SDB, there were 248 cases (18.14%) with continuous mild SDB, 395 cases (28.90%) with moderate SDB, 295 cases (21.58%) with severe SDB, and 282 cases (20.63%) that fluctuated between different severity levels. Within this fluctuating group, 152 cases (53.90%) fluctuated between two severity levels, 120 cases (42.55%) between three levels, and 10 cases (3.55%) among all four levels. There were statistically significant differences (P < 0.05) in the sleep latency, sleep efficiency, non-rapid eye movement stages 1-2, rapid eye movement, proportion of non-rapid eye movement, proportion of rapid eye movement, wake after sleep onset, time out of bed, number of awakenings, respiratory variability index, and heart rate variability index among patients with ACI monitored from day 1 to 5. However, other monitored sleep structure parameters did not show statistically significant differences (P > 0.05). The coefficient of variation for all sleep monitoring parameters ranged between 14.54 and 36.57%. The IV in the SDB group was higher than in the group without SDB (P < 0.05), and the IS was lower than in the group without SDB (P < 0.05).

CONCLUSION

Patients in the acute phase of cerebral infarction have a high probability of accompanying SDB. The sleep structure of these patients shows significant variability based on the onset time of the stroke, and some patients experience fluctuations among different severity levels of SDB. ACI accompanied by SDB can further reduce the IS of a patient's sleep circadian rhythm and increase its IV.

Ticking Brain: Circadian Rhythm as a New Target for Cerebroprotection

Circadian rhythm is a master process observed in nearly every type of cell throughout the body, and it macroscopically regulates daily physiology. Recent clinical trials have revealed the effects of circadian variation on the incidence, pathophysiological processes, and prognosis of acute ischemic stroke. Furthermore, core clock genes, the cell-autonomous pacemakers of the circadian rhythm, affect the neurovascular unit-composing cells in a nonparallel manner after the same pathophysiological processes of ischemia/reperfusion. In this review, we discuss the influence of circadian rhythms and clock genes on each type of neurovascular unit cell in the pathophysiological processes of acute ischemic stroke.

Molecular circadian markers in acute ischemic stroke (preliminary results)

Background. Ischemic stroke is the leading cause of mortality and loss of working ability. Sleep disorders and sleep-wake rhythm disorders are considered to be a potential modifiable risk factor of acute stroke. Objective. To determine the peculiarities of circadian rhythms in acute stroke by assessing the daily variation of urinary excretion of cortisol and 6-sulfatoxymelatonin. Materials and methods. We examined 27 patients with acute ischemic stroke and 9 patients admitted to the hospital with suspected but not confirmed stroke. All examinations in both groups were performed in similar settings. All patients underwent neurological assessment in acute phase and before discharge including evaluation by National Institute of Health Stroke Scale, modified Rankin scale (mRs), Barthel index and Rivermead index. Within 48–72 hours after admission, urine samples were collected at 7 a. m., 3 p. m. and 11 p. m. for cortisol and 6-sulfatoxymelatonin assessment (enzyme-linked immunosorbent assay analysis). Results. Daily urinary cortisol excretion did not differ in stroke and control subjects. However, stroke patients demonstrated the highest values in the evening while control subjects had higher levels in the morning. The rhythm of urinary 6-sulfatoxymelatonin excretion is preserved in both groups with the highest level in the morning. However, stroke patients show lower levels at all time points (by 45 %, 33 % and 72 % in the morning, afternoon and evening, respectively). There were no changes in either cortisol or 6-sulfatoxymelatonin excretion depending on stroke severity. Afternoon excretion of 6-sulfatoxymelatonin correlates with Barthel index at discharge (ρ = 0,63; p = 0,004), mRs score at discharge (ρ = –0,65; p = 0,003) and Rivermead index at admission (ρ = 0,52; p = 0,024) and at discharge (ρ = 0,49; p = 0,032). Conclusion. Patients with acute mild-moderate stroke show abnormal daily rhythm of urinary cortisol excretion with the maximum in the evening. The daily rhythm of 6-sulfatoxymelatonin excretion is preserved with the maximum excretion at night, but stroke patients have lower levels compared to control subjects.

Stroke in the Time of Circadian Medicine

Time-of-day significantly influences the severity and incidence of stroke. Evidence has emerged not only for circadian governance over stroke risk factors, but also for important determinants of clinical outcome. In this review, we provide a comprehensive overview of the interplay between chronobiology and cerebrovascular disease. We discuss circadian regulation of pathophysiological mechanisms underlying stroke onset or tolerance as well as in vascular dementia. This includes cell death mechanisms, metabolism, mitochondrial function, and inflammation/immunity. Furthermore, we present clinical evidence supporting the link between disrupted circadian rhythms and increased susceptibility to stroke and dementia. We propose that circadian regulation of biochemical and physiological pathways in the brain increase susceptibility to damage after stroke in sleep and attenuate treatment effectiveness during the active phase. This review underscores the importance of considering circadian biology for understanding the pathology and treatment choice for stroke and vascular dementia and speculates that considering a patient's chronotype may be an important factor in developing precision treatment following stroke.

Correlation of Circadian Rhythms and Improvement of Depressive Symptoms in Acute Ischemic Stroke Patients

OBJECTIVES

To investigate the correlation between evening melatonin timing secretion, dim light melatonin onset (DLMO), and post-stroke depression (PSD) in acute ischemic stroke patients and their influence on the improvement of depressive symptoms.

MATERIALS AND METHODS

120 patients with a recent magnetic resonance imaging confirmed stroke were included. Salivary melatonin samples were collected at 5 time points within 1 week after hospitalization (7 p.m.-11 p.m., 1 sample per hour). The circadian phase was defined by calculating DLMO secretion. Post-stroke depressive symptoms were evaluated by the 17-item Hamilton Rating Scale for Depression (HRSD) both on day 7 of hospitalization and 3 months after stroke. Patients were divided into PSD and non-PSD groups based on whether the acute phase HRSD score was ≥8. Similarly, patients were divided into the improved depressive symptoms (IDS) and no improvement in depressive symptoms (non-IDS) groups based on whether the HRSD score at 3 months was lower than at baseline. Neurological recovery at 3 months was assessed using the modified Rankin Scale (mRS).

RESULTS

The difference in DLMO between PSD and non-PSD patients was not statistically significant (p =0.173). In the non-IDS group, there was a significant decrease in melatonin secretion at 10 p.m. (p =0.012), and DLMO was significantly later than in the IDS group (p =0.017). Logistic regression analysis showed that DLMO (OR 1.91, 95%CI:1.13-3.23, p = 0.016) was an independent risk factor for persistent no improvement in depressive symptoms, which was associated with a markedly worse prognosis (p <.001).

CONCLUSION

Our findings suggest possible interventions for the very early identification of non-IDS patients.