Proteolysis in severe sepsis is related to oxidation of plasma protein

To test the hypothesis that the oxidation of proteins is part of the mechanism of proteolysis in catabolic states.

Prospective, observational study.

Critical care unit at a university teaching hospital, New Zealand.

13 patients (6 male, 7 female; median age 61, range 26-76 years) who were admitted to the Department of Critical Care Medicine at Auckland Hospital with a diagnosis of severe sepsis. The median APACHE II score during the first 24 hours after admission was 22 (range 15-34). Control values of protein carbonyl in plasma were established in 15 healthy volunteers.

We made serial measurements of total body protein (by neutron activation analysis) and plasma protein carbonyl (by ELISA) concentrations over a period of 10 days.

Plasma protein carbonyl concentration and total body protein.

The total amount of body protein decreased significantly over the 10 days (p < 0.001). Plasma protein carbonyl concentrations were significantly higher in the septic patients than in the control group throughout the study period (p < 0.0001). There was a significant reduction in plasma protein carbonyl concentration over the study period (p < 0.008). The early increase in the concentration of protein carbonyl formation was followed by an ongoing loss of body protein. There was a significant positive correlation between total body protein and plasma protein carbonyl (p < 0.03).

Severe sepsis results in oxidation of plasma proteins and this precedes and is related to the loss of body protein.