Mechanisms of chronic stress influence on the brain hemodynamic in persons with employment-related chronic stress

OBJECTIVE: To discuss the mechanisms by which chronic psychosocial stress (CPSS) affects the parameters of cerebral blood flow. MATERIAL AND METHODS: One hundred and sixty locomotive machinists (LM) and machinist assistants (MA), whose profession is rated as one of the most stressful, were enrolled in this study. The control group consisted of 100 healthy volunteers. The activity of the stressor system was assessed by the levels of stress hormones in serum (ACTH, cortisol, adrenaline). The functional state of the endothelium was assessed by secretion of nitric oxide and endothelin-1. Doppler ultrasound was used to measure the linear velocity of blood flow in the cerebral vessels, the size of the intima-media complex of the common carotid artery, and the results of the endothelium-dependent vasodilation. Blood pressure was monitored daily. RESULTS: The action of CPSS is accompanied by the persistent increase in the serum cortisol levels. This process contributes to the development of vasoconstriction with the initiation of endothelial dysfunction with impaired production of nitric oxide and increased secretion of endothelin-1 and the formation of arterial hypertension. With progression of these processes, there is a decrease in cerebral blood flow. The observed increase in the size of the intima-media complex of the common carotid artery correlates with the severity of arterial hypertension and endothelial dysfunction. CONCLUSIONS: CPSS leads to a decrease in cerebral blood flow and subsequent development of endothelial dysfunction and arterial hypertension, which are related to high levels of stress hormones circulating in the blood. These processes lead to functional failure of the vascular endothelium.