PP027-SUN BIOMARKERS OF SELENIUM STATUS IN CRITICALLY ILL PATIENTS

Abstract

Rationale: Deficient status in selenium, a cofactor of the antioxidant enzyme glutathione peroxidase (GPx), together with hypercatabolic state, can affect the clinical course during the patient’s stay in the intensive care unit (ICU). The resulting increase in oxidative stress has been recognized as a central mechanism in the pathophysiology of critical illnesses, particularly the appearance of multiorgan failure. Methods: A blood sample was obtained on the day of admission in the ICU from 65 critically ill patients in Granada province (southern Spain) who fulfilled the inclusion criteria. Selenium was measured with inductively coupled plasma mass spectrometry (ICP-MS). GPx was measured indirectly as enzyme activity (reduction of organic peroxides by c-GPx), and selenoprotein P was measured by SEPP1 enzyme-linked immunoassay. Results: On admission to the ICU, GPx enzyme activity was below the reference value ( 24 U/mL). Mean plasma concentration of selenium was 56±12.9mg/dL, and on the day of admission 67.7% of the patients were selenium deficient. By day 7 of their ICU stay this proportion had increased significantly to 100% (p < 0.05). Below-normal values of SEPP1 (<3.43 mg/L) were found in 77.3% of the patients on the day of admission, and this proportion had increased to 100% by the end of their ICU stay. Conclusion: During their ICU stay, antioxidant GPx enzyme activity increased and plasma concentration of selenium decreased in the patients we studied. This selenium deficiency can lead to increased stress and increased demands on endogenous antioxidant synthesis. Selenium intake should be monitored in order to ensure optimum antioxidant response and palliate the adverse effects of this nutritional deficiency.