Influence of drotrecogin alpha (activated) infusion on the variation of Bax/Bcl-2 and Bax/Bcl-xl ratios in circulating mononuclear cells: A cohort study in septic shock patients

Objective. Drotrecogin alpha (activated) (DAA), or recombinant human activated protein C, is a new treatment in sepsis-induced multiple organ failure, leading to significant reduction in the mortality rate, thanks to its anticoagulant properties. It has been suggested that DAA has anti-inflammatory and antiapoptotic effects in sepsis animal models. This study investigates the potential actions of DAA on circulating mononuclear cells apoptosis in human septic shock. Design., Prospective, cohort study. Setting. Two intensive care wards and two research laboratories in a university hospital. Patients. Twenty-two septic shock patients with DAA treatment (DAA+), 19 septic shock patients without DAA treatment (DAA-), and 14 healthy controls were successively enrolled, but only 20 DAA+ and 16 DAA- patients fulfilled criteria for statistical analysis. Interventions., Blood samples were collected at inclusion and 24 hrs later. Measurements and Main Results., Circulating mononuclear cell apoptosis levels were assessed by flow cytometry with annexin V, and variations of the apoptotic rheostats (Bax/Bcl-2 and Bax/Bcl-xl ratios) were analyzed by real-time reverse transcription-polymerase chain reaction. Apoptosis was significantly increased in septic shock patents (DAA+, 12 +/- 6.4%; DAA-, 10.4 +/- 5%) vs. healthy patients (3.4 +/- 2.1%, p <.001). Twenty-four hours after DAA infusion, apoptosis was significantly lower in the DAA+ group compared with DAA- ones (respectively, 11.7 +/- 5.3% and 16.2 +/- 7.6%, p <.001). At inclusion, DAA+ and DAA- groups showed comparable Bax/ Bcl-2 ratio (DAA+, 0.92 +/- 0.9; DAA-, 1.32 +/- 0.87) and Bax/BcI-xl ratio (DAA+, 2 +/- 1.04; DAA-, 1.31 +/- 0.93). In contrast, 24 hrs later we observed a significant decrease in these ratios, indicating an antiapoptotic effect in the DAA+ group (Bax/Bcl-2, 0.39 +/- 0.27; Bax/Bcl-xl, 0.68 +/- 0.35) compared with the DAA- group (Bax/Bcl-2, 1.81 +/- 1.1; Bax/Bcl-xl, 1.22 +/- 0.92, p =.001 and p =.039, respectively). Conclusions: In vivo, in human septic shock, DAA has antiapoptotic effects on circulating mononuclear cells, assessed by a significant decrease of both the Bax/Bcl-2 and Bax/Bcl-xl ratios.