Acute lung injury (ALI) and
sepsis are the major causes of mortality in intensive care units. Lymphocytes apoptosis is a hallmark feature of late detrimental
sepsis.
Parenteral nutrition in
critically ill patients is based on
lipid emulsions, but the impact of ALI and
lipid emulsions on lymphocytes has not been defined. The effects of intravenously infused conventional
soybean oil (SO)-based and new
olive oil (OO)-based
emulsions on splenic and blood lymphocytes were investigated in a murine model of
endotoxin-induced ALI. After LPS challenge and infusion of
lipid emulsions, apoptosis of lymphocytes and
lung injury were assessed by flow cytometry, Western blot, and histology. Induction of ALI led to a time-dependent decline in splenic and circulating lymphocyte numbers and an increase in apoptosis, with engagement of the extrinsic apoptotic pathway. Both SO- and OO-based
emulsions promoted the apoptosis of splenic lymphocytes before induction of ALI. The OO-based
emulsions exhibited lower proapoptotic activity than did SO-based
emulsions, an observation paralleled by the induction of survival factors. Induction of ALI increased the mortality of mice receiving SO-based
emulsions compared with OO-based
emulsions and
normal saline. Splenic lymphocyte apoptosis is apparent in murine ALI, which may be linked to detrimental outcome. Infusion of
lipid emulsions per se provoked splenic lymphocyte apoptosis. Infusion of SO-based
emulsions further augmented the apoptosis of splenic and circulating lymphocytes in ALI and led to increased mortality in mice. These findings may be of relevance for patients experiencing ALI that require
parenteral nutrition.