Investigation of the relationship of serum glutamine level and oxidative stress parameters with stroke severity i̇n ischemic stroke patients in the neurology intensive care unit

Stroke is a condition characterized by rapidly developing clinical signs of focal (or global) cerebral dysfunction with no apparent cause other than vascular causes. Knowledge of stroke risk factors and a good understanding of its physiopathology are crucial for the development of preventive and effective therapeutic strategies. The role of oxidative stress in the physiopathology of ischemic stroke is known. However, it is not clear to what extent oxidative stress affects stroke severity. Therefore, in our study, we aimed to examine the relationship between TAS and TOS levels, which are oxidative stress parameters, and stroke severity in ischemic stroke patients. As a component of acute stress response in stroke patients, hormone levels such as glucagon, catecholamine and cortisol increase in the blood circulation, interleukins and acute phase proteins increase. This stress response causes catabolic destruction of muscle and adipose tissue. As a result, various amino acids such as glutamine are released from muscle tissue by increased proteolysis and rapidly taken up from the blood by other tissues in need. Since the rate of synthesis cannot compensate the increased demand, glutamine deficiency may occur in critically ill patients. Therefore, we aimed to examine glutamine levels in patients with ischemic stroke. The study included 50 patients admitted to the Dicle University Faculty of Medicine, Neurology Intensive Care Unit between June 2023 and November 2023 with a diagnosis of ischemic stroke. Blood samples were collected from all patients three times, on intensive care unit admission and on the 4th and 10th days of hospitalization. Glutamine, TAS and TOS levels were analyzed. To determine the severity of stroke, the NIHSS score was calculated upon admission to the intensive care unit. On admission to the intensive care unit, the mean glutamine level was 611.0 (±155.7) μmol/L, which was within the normal range. %14 (n=7) of patients had deficient (<420 μmol/L) and 2% (n=1) had supra-normal glutamine levels (>930 μmol/L) on admission. As a result of the course of hypercatabolism in critically ill patients, glutamine deficiency on days 4 and 10 of hospitalization rather than admission to the ICU is highly valuable. In 22% of patients (n=11), glutamine levels were low (<420 μmol/L) on day 4 and/or day 10. 72.7% of the patients with low glutamine levels were in the severe stroke category. There was no significant difference between gender and glutamine levels. Glutamine levels on admission to intensive care unit and on the 10th day of hospitalization were significantly lower in patients who died than in patients who stayed alive (p values 0.020, 0.004, respectively). There was no significant correlation between glutamine levels and NIHSS scores. The mean TOS level was 23.0 (±17.2) µmol Eq/L, which was well above the normal level. The mean TAS level was 1.22 (±0.51) mmol Eq/L, which was in the normal range. There was no significant correlation between TAS and TOS levels and NIHSS score. As a result, it was observed that some ischemic stroke patients had glutamine deficiency. It was found that 72.7% of ischemic stroke patients with low glutamine levels were in the severe stroke category. Therefore, it should be kept in mind that glutamine deficiency may be present especially in patients in the severe stroke category. In addition, since low glutamine levels have been found to be significantly associated with mortality, we believe that giving glutamine supplements to patients with low glutamine levels may be life-saving. Therefore, larger scale studies are needed to evaluate glutamine levels in ischemic stroke patients. In addition, high TOS levels in patients indicate the presence of oxidative stress in ischemic stroke patients. The lack of a significant relationship between TAS and TOS levels and stroke severity suggests that oxidant and antioxidant levels are not effective in determining stroke severity. Keywords: Ischemic stroke, Glutamine, Stroke Severity, Oxidative Stress, Total Antioxidant Status (TAS), Total Oxidant Status (TOS)