Composés séléniés et sélénium, quelle place en réanimation ?

Septic shock, and related syndromes, are the most common causes of death in ICU patients. In sepsis, endothelium damage and oxidative stress, at the microcirculation level, may cause multiple organ failure and death. Selenium (Se) is an atom with oxidant and antioxidant properties. Indeed, as an essential trace element, it has crucial antioxidant properties in human when incorporated into seleno-enzymes. Nonorganic seleno-compounds are more or less oxidant. Among proteins that contain selenium, seleno-protein P (Sel-P) accounts for 55% of the plasma in healthy individuals but may dramatically decrease in septic shock patients. Moreover recent animal studies suggest that this decrease may precede hemodynamic disorders. In addition to transport function, Sel-P may also bind the endothelium to protect it against oxidative stress. Sel-P as an early marker of septic shock and related organ dysfunctions need further studies. If clinical data suggest that an intake of Se in ICU patients from 50 to 200 μg per day is safe and recommended, results of recent Phase II studies support that a bolus of high dose of sodium selenite - an oxidant seleno-compound - may be beneficial in septic shock patients. A recent animal study supports the beneficial effect of bolus. This is the first septic shock therapeutic approach assimilating septic shock to an acute hematological disease where increasing transiently oxidative stress leads to decreased inflammation. However, seleno-compounds are highly toxic. Further studies are required before recommending intravenous administration, especially in bolus, of seleno-compounds like sodium selenite, at doses above the upper limit of 400 μg per day.