Association of autonomic nervous system functions with immune response and prognosis in acute ischemic stroke patients

Aim. Cerebrovascular disease is the most commonly encountered condition which causes serious mortality and morbidity in neurological practice. It has been reported that heart rate variability declines in a cerebrovasculer disease, which shows that autonomic functions are affected. Autonomic nervous system has a significant role in monitoring immune status and controlling inflammation. Similarly, there are studies reporting that immune system is affected during acute phase of cerebrovascular diseases. In the present study, our aim was to investigate the effect of autonomic nervous system on immune response and prognosis in acute ischemic cerebrovascular diseases. Method. 44 patients with middle cerebral artery infarction and 44 healthy controls were included in this study. Autonomic nervous system was evaluated using a methodology analysing the heart rate variability based on frequency. In order to evaluate the effects on immun system, serum levels of interleukin 1β, interleukin 6, tumor necrosis factor alfa and interleukin 10 were measured on the 1 st , 3 rd , 7 th and 10 th day by ELISA. Prognosis was evaluated by Rankin scale after 3 months. Results. Compared to the controls, low frequency power in normalized units (LFnu) was found to be high, high frequency power in normalized units (HFnu) was found to be low and ratio of LFnu/HFnu was found to be high in the patients group. The increase being more marked in left middle cerebral artery infarctions, interleukin-6 level were increased on the 10 th day and interleukin-10 level was decreased at all days compared to baseline in all patients. Interleukin-1β and tumor necrosis factor α levels were lower in all patients but the decrease was more pronounced in patients having left middle cerebral artery infarction. There was no difference between the Rankin scores of the patients having right and left middle cerebral artery infarction. Conclusions. Ischemic cerebrovascular disease is associated with an effect on immune system. This impaired immun response can be correlated both with a decreased parasympathetic activity and an increased sympathetic activity particularly in patients with middle cerebral artery infarctions.