Molecular circadian markers in acute ischemic stroke (preliminary results)

Abstract

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.